Vyhledávání

Determination of chromium in leather waste solutions in the range between 1000 and 30,000 ppm.

Determination of free acid in copper refining solutions.

Determination of moisture in lubricating oils with TEOF (triethyl orthoformate).

Determination of nickel in the absence of cobalt and other interferences.

Determination of tar acids in coal tar products. This procedure may also be applied to the determination of a range of weakly acidic organic compounds such as carboxylic acids, hydroxy acids, phenols, phenolic acids, keto-enols, imides, and aromatic nitro compounds.11 Vaughan, G. A. Thermometric and Enthalpimetric Titrimetry. Van Nostrand Reinhold Co. Ltd (1973)

Determination of water in automotive lubricating oils.

This Application Note describes a method for the determination of causticizer, carbonate and aluminum oxide in used Bayer process liquors. The method is based on processes that were developed by Watts-Utley and VanDalen-Ward.

Determination of total basicity of extractable organic compounds of acidic character in Bayer process refinery liquors.

Standardization of 0.1 mol/L in propan-2-ol for use in applications for the determination of weakly acidic species in non-aqueous media.

Determination of chlorite by direct thermometric titration with standard sodium thiosulfate solution. The procedurewas applied originally to the determination of chlorite in hide treatment solutions.

Determination of low levels of sulfate (to approximately 20mg/L SO42-) by thermometric titration.

Standardization of 0.1 mol/L ammonium ferrous sulfate solution for use in thermometric titration of Cr(VI) solutions.

Determination of low levels of chloride (to approximately 5 mg/L Cl-) by thermometric titration.

Determination of calcium and magnesium in process solutions.

Phosphorus is a primary macronutrient for plants and is a constituent of DNA and adenosine triphosphate (ATP), which is involved in many biological processes requiring energy. In fertilizers, phosphorus is present in the form of phosphate, as the most accessible form of phosphorus for plants is dihydrogen phosphate. Knowledge of the phosphorus content helps to select the right fertilizer for the plants.Traditionally, phosphate is determined gravimetrically (a time consuming procedure) or spectrophotometrically (expensive instrumentation). In this Application Note, an alternative method is presented, where phosphate is determined by a precipitation titration with magnesium. Various solid and liquid NPK fertilizers with phosphorus contents between 6.5 and 17% were analyzed. The analysis by thermometric titration requires no sample preparation in case of liquid NPK fertilizers and only minimal sample preparation in case of solid NPK fertilizers. One determination takes about 5 minutes.

Determination of free fatty acids (FFA) in oils.

Determination of phosphate content in an acid etching bath.

Determination of sulfate and total acids in a nitrating mixture.

Determination of sodium lauryl ether sulfate surfactants.

Determination of low content of HCl (around 10 ppm) in silicone oil.

Standardization of cetyl pyridinium chloride solutions for use as a cationic surfactant titrant in the determination ofanionic surfactants such as sodium lauryl ether sulfate.

This Application Note discusses the standardization of thiosulfate titrant for use in the determination of copper with thermometric titration.

Determination of copper, principally in copper mining and refining solutions. The method may also be used fordetermination of purity of copper metal. Optimal results are obtained when aliquots containing copper in the rangeapproximately 3 - 6 mmol Cu are titrated.

Thermometric complexometric titration of metals is often performed with tetrasodium EDTA. This Application Note explains the standardization of tetrasodium EDTA titrant with copper.

This Application Note explains how to use magnesium to standardize tetrasodium EDTA titrant.

Standardization of copper back-titrant using standard tetrasodium EDTA titrant in the determination of metals.

Determination of nickel in refinery and plating solutions. When other metals capable of being complexed by EDTA are present, these will interfere and enhance the result for nickel.

Standardization of disodium dimethylglyoximate by thermometric titration with standard Ni(II) solution.

Determination of nickel in solution by titration with standard disodium dimethylglyoximate.

Determination of sodium, potassium, and silica values in sodium and potassium silicates.

Determination of sodium hypophosphite in electroless plating solutions.

Thermometric titration of nickel in electroless plating solution with disodium dimethylglyoximate.

Determination of aluminum in acidic, basic, and neutral solutions; including aluminum chloride, aluminum chlorohydrate (also in anti-perspirant formulations), alum, etching solutions, and aluminate solutions.

Determination of Na, P, and [Na]/[P] in precursor solutions and solids in the manufacture of sodium tripolyphosphate.

Standardization of barium acetate titrant used in the determination of sulfate in phosphoric acid. The same procedure is applied if barium chloride is chosen as the titrant.

Standardization of sodium fluoride titrant for determination of aluminum.

Determination of sodium as chloride in ketchups, sauces and, similar food products.

Standardization of 0.1mol/L perchloric acid in glacial acetic acid by catalyzed endpoint thermometric titration.

Determination of sodium in salts, process solutions, and foods.

Standardization of titrant for direct determination of sodium.

The determination of the total base number (TBN) in motor oils is accomplished by means of titration with a standard solution made up of trifluoromethanesulfonic acid in glacial acetic acid and isobutyl vinyl ether as reagent for improved end point identification.

Determination of sodium and potassium salts of carboxylic acids in aqueous media. May be used for analysis of reagent purity.

Determination of bicarbonate and carbonate in a mixture by sequential thermometric titrations.

Determination of chloride in Bayer process liquor.

Determination of Fe3+ by iodometric titration. Useful if Fe3+ is accompanied by Al3+, Mg2+, Ca2+ and Fe2+.

Determination of Fe3+ and Cu2+ in copper refining solutions by thermometric titration. It was found that the conventional approach of masking Fe3+ to permit the iodometric determination of Cu2+ is not possible in some copper refining solutions.

Determination of ammonium ions in ammonium salts and mixtures containing ammonium ion.

Determination of Total Acid Number (TAN) values in biodiesel to <0.05 mg KOH/g sample.

Determination of calcium and magnesium in seawater. The method is suitable for determining the effect of caustic soda and alumina refinery aluminate solutions on the calcium and magnesium content of seawater.

Standardization of ~1mol/L tetrasodium EDTA solutions for thermometric complexometric analysis.

Iodine value (IV) is a measure of the total number of double bonds present in fats and oils. It is expressed as the «number of grams of iodine that will react with the double bonds in 100 grams of fats or oils». The determination is conducted by dissolving a weighed sample in a non-polar solvent such as cyclohexane, then adding glacial acetic acid. The double bonds are reacted with an excess of a solution of iodine monochloride in glacial acetic acid («Wijs solution»). Mercuric ions are added to hasten the reaction. After completion of the reaction, the excess iodine monochloride is decomposed to iodine by the addition of aqueous potassium iodide solution, which is then titrated with standard sodium thiosulfate solution.

Determination of sodium in seawater and similar brines. This procedure is suitable for the analysis of sodium in seawater contaminated with sodium aluminate solutions emanating from alumina refineries, and seawater which has been used for the neutralization of alumina refinery waste («red mud») slurries.

Determination of total halides (Cl- + Br- +I-) in seawater and similar brines. This procedure is suitable for the analysis of total halides in seawater contaminated with sodium aluminate solutions emanating from alumina refineries, and seawater which has been used for the neutralization of alumina refinery waste («red mud») slurries. Given the small concentration of bromine andiodine in seawater, the total halide content approximates the chloride concentration.

Determination of free acid in sulfuric acid («acid shot») solutions employed in the removal of silicate scale in heat exchangers. This method is suitable for acid shot solutions where the silicic acid content is so high that the solutions have gelled.

Determination of the total sodium content of sodium aluminate liquors, such as Bayer Process liquor. This method is suitable for the analysis of all sodium aluminate solutions down to at least 1 g/L as Na2CO3. The determination may be automated by adding an 814 USB sample processor to an 859 Titrotherm.

Determination of phosphoric and nitric acids in liquors from the Nitrophos fertilizer manufacturing process.

This Application Note outlines the determination of total acidic active surface sites in zeolites with thermometric titration.

This Application Note shows that the parameter of surface basicity of zeolites can be measured by thermometric titration.

Determination of mixtures of sulfuric, phosphoric, and nitric acids. The procedure is suitable for automated analysis using an 814 Sample Processor.

Titration of an unfiltered suspension of the sample with a standardized solution of aluminum containing a stoichiometric excess of potassium ions in the presence of ammonium hydrogen difluoride at ~ pH 3 to give an exothermic reaction, forming insoluble NaK2AlF6. The titrant is standardized against a solution prepared from anhydrous sodium sulfate or sodium carbonate. In addition to this application note, you can find more information on thermometric sodium determination in foods in our application video available on YouTube: https://youtu.be/lnCp9jBxoEs

Determination of hydrofluoric acid in mixed acid etchant solutions.

Automated determination of total acid number (TAN) in new and used lubricating oils and crude oils using the 814 USB Sample Processor. Dissolve oil sample in mixture of toluene and 2-propanol, add paraformaldehyde and titrate with 0.1 mol/L or 0.01 mol/L KOH in propan-2-ol. The endpoint is indicated by an endothermic response caused by the base-catalyzed depolymerization of paraformaldehyde.Reference: 1. M. J. D. Carneiro, M. A. Feres Júnior, and O. E. S. Godinho. Determination of the acidity of oils using paraformaldehyde as a thermometric end-point indicator. J. Braz. Chem. Soc. 13 (5) 692-694 (2002)

Automated determination of the H2SiF6 and HF contents of industrial grade hexafluorosilicic acid.

Automated thermometric titration of the nickel content of electroless nickel plating solutions. The determination is suitable for fully automated titration employing a 814 Sample Processor.

Standardization of 1 mol/L tetrasodium EDTA (Na4EDTA) solutions by titration with standard magnesium solution.

Automated determination of the zirconium content of zirconium acetate, as well as other zirconium compounds which can be rendered soluble as zirconium acetate.

Determination of boric acid in electroless plating solutions.

Determination of boron in ores of the element such as borax and ulexite.

Dissolution of urea in glacial acetic acid, and titration with standard 0.1 mol/L trifluoromethanesulfonic acid in acetic acid using isobutyl vinyl ether as a thermometric endpoint indicator.

Dissolution of oil in toluene, and titration with standard 0.1 mol/L trifluoromethanesulfonic acid in acetic acid using isobutyl vinyl ether as a thermometric endpoint indicator.

A measured amount of salt is titrated directly with a solution of 1 mol/L tetrasodium EDTA to thermometrically determined endpoints for Ca and Mg. Acetylacetone is added to alter the Ca and Mg EDTA stability constants for better endpoint sharpness.

This Application Note describes the determination of fluoride in silicon etch solutions with thermometric titration.

Determination of the total acids concentration in mixtures of nitric-hydrofluoric acid intended for etching silicon substrates.

A sample of concentrated mineral acid is dissolved in anhydrous acetonitrile, and the water content titrated with a solution of TEOF in acetonitrile. The TEOF reacts exothermically with water in the presence of a strong acid (acting as a catalyst).

Hypochlorite ions react with bromide ions to form hypobromite ions, which in turn rapidly oxidize ammonium ions to nitrogen. Hypobromite reacts more rapidly with ammonium than hypochlorite, and is formed in situ (Vogel, 1961). The titration is carried out with in a solution containing bromide and bicarbonate.

A measured amount of milk is treated with trichloroacetic acid to coagulate milk solids and liberate calcium and magnesium as dissociated ion. The coagulated milk is filtered or centrifuged, and an aliquot of the clear serum is titrated with a standard solution of 1 mol/L tetra-sodium EDTA to thermometrically determined endpoints for Ca and Mg. Acetylacetone is added to alter the Ca- and Mg- EDTA stability constants for better endpoint sharpness.

A measured amount of acidic hydrometallurgical leach liquor is treated with potassium oxalate solution to mask potential interference from Fe(III) and other metal ions, and then titrated with standard 1 mol/L NaOH solution.

A measured amount of acidic hydrometallurgical leach liquor is first treated with hydrogen peroxide to oxidize Fe(II) to Fe(III), then with potassium pyrophosphate solution to mask interference from Fe(III) and other metal ions. Ammonium acetate solution is then added as a pH modifier, before being titrated with standardized disodium dimethylglyoximate to an exothermic endpoint.

A measured amount of acidic hydrometallurgical leach liquor is treated first with a complexing agent (sodium gluconate). It is then basified to ~pH 10.5 with a NH3 /NH4Cl buffer, prior to the addition of KCN solution to mask Fe(III). Caution! Do not add KCN to solutions of pH below 9! The Fe(III) is then reduced to Fe(II) by additon of ascorbic acid, prior to titrating the Mg content with standard Na4EDTA solution.

A measured amount of acidic hydrometallurgical leach liquor is further acidified with sulfuric acid, prior to being titrated with standard potassium dichromate solution to an exothermic endpoint. Thus, 1 mol K2Cr207 ≡ 6 mol Fe2+.

A measured amount of acidic hydrometallurgical leach liquor is pH modified with a small amount of glacial acetic acid, and the Fe(III) content reduced to Fe(II) with iodide ion. The liberated iodine is titrated with standard thiosulfate solution to an exothermic endpoint. Thus, 1 mol Fe3+= 1 mol S2O32-.

Results from three separate single endpoint titrations are used to calculate the results. The mixture of H2SO4, HF, and NH4F/HF contains H+ from H2SO4, HF, and NH4F/HF, SO42- from H2SO4, and F- from HF and NH4F/HF. Analysis of total H+ («total acids») by NaOH titration, F- by titrating with Al(NO3)3 («total fluoride») and SO42- by titrating with BaCl2 provides the information required to determine the composition of the mixture.

Sulfate is precipitated by reaction with an acidified barium chromate solution. The excess barium chromate is precipitated by basification with ammonia solution. Residual soluble chromate equivalent to the sulfate content of the sample is titrated with a solution of standard ferrous ion to a thermometrically determined endpoint.

Sulfate is precipitated as barium sulfate by reaction with an acidified barium chromate solution. The excess barium chromate is precipitated by basification with ammonia solution. Residual soluble chromate, equivalent to the sulfate content of the sample, is titrated with a solution of standard ferrous ion to a thermometrically determined endpoint.

Two separate titration sequences are required to analyze the mixture:- titration of the HF content with Al(NO3)3 (the «elpasolite» reaction)- titration of the H2SO4 with BaCl2 followed by titration with NaOH to determine the «total acids» contentThe HF, H2SO4, and «total acids» contents are converted to a HNO3 equivalent, with the HNO3 content found by subtracting the HF and H2SO4 from the «total acids» content.

A direct thermometric titration (TET) with 2 mol/L NaOH is used to determine the HF, NH4F, and maleic acid (C4H4O4) contents of acid cleaning solutions. Three endpoints (EPs) are obtained, which may be assigned as follows:EP1: C4H4O4 (pKa1 = 1.9), HF (pKa = 3.17)EP2: C4H4O4 (pKa2 = 6.07)EP2: NH4F (pKa = 8.2)The HF content is determined by subtracting the difference (EP2-EP1) from EP1.

This Application Note supplements AN-H-003 with the treatment of the standard addition of sulfate as sulfuric acid. This technique may be contemplated when either sulfate levels are too low for a satisfactory direct titration, or when the sample matrix hinders endpoint detection, leading to poor precision and accuracy.

This Application Note describes the determination of the free and total hydroxide and aluminum oxide content in Bayer process and other aluminate liquors. The method is not subject to interference by carbonate ions. An aliquot of sodium aluminate liquor is titrated with potassium hydrogen carbonate solution to yield the free hydroxide ion content of the liquor.

The presence of the hydrated ion [Fe(H2O)6]3+ can interfere with the determination of «free acid» due to the low pKa value (~2.2) of this ion. Ions of metals such as Fe, Cu, and Al can be masked effectively with fluoride, and permit the determination of the acid content by thermometric alkalimetric titration with good accuracy and precision.

This Application Note deals with the determination of ferric ion in acidic and copper-free solutions using thermometric titration. The ferric ion is reduced by iodide. The released iodine reacts exothermically when titrated with thiosulfate solution. The endpoint is determined through temperature plotting by the temperature sensor Thermoprobe.

This Application Note describes the determination of aluminum ion down to approximately 0.5 g/L in acidic solutions containing ferric, ferrous, and other ions whose hydroxides do not dissolve in strongly basic solutions.

This Application Note looks at the determination of ferrous ion in acidic solutions from approximately 0.25 g/L by thermometric titration with ceric titrant. The exothermic oxidation reaction shows a sharp endpoint that is detected using the Thermoprobe as a sensitive temperature sensor.

This Application Note describes the determination of total sodium content in canned fish products using thermometric titration. In addition to this application note, you can find more information on thermometric sodium determination in foods in our application video available on YouTube:https://youtu.be/lnCp9jBxoEs

This Application Note describes the determination of the total sodium content in instant noodles which are also called «two minute noodles» in some countries. These products contain considerable amounts of sodium (at least 50% of the recommended daily dosage), which means that precise analysis of the sodium content is required. Argentometric titration of the chloride content (assuming that the sodium content in the noodles originates exclusively from the sodium chloride that is added to them) is unsuitable for precise analysis, as the nutrient contents listed on the product packaging document the presence of additional sodium salts other than sodium chloride. Thermometric titration enables fast and direct determination of sodium. In addition to this application note, you can find more information on thermometric sodium determination in foods in our application video available on YouTube:https://youtu.be/lnCp9jBxoEs

This Application Note describes the determination of the total concentration of sodium in precursor solutions used in the manufacturing of margarine. The solutions of the precursors are mixed with edible fats and oils to make margarine. Traces of sodium chloride and other sodium and potassium salts may be added to the margarine during this process, usually in the form of emulsifiers, stabilizers, antioxidants, vitamins, coloring agents or flavor enhancers. The analysis of the total sodium content in the precursor solutions is more efficient and cost-effective for the manufacturers than later total sodium content analyses in the final product.As a rule, argentometric titration of chloride is used for indirect determination of the sodium content of foodstuffs. The assumption behind this approach is that the chloride ions are present in a molar ratio of 1:1 with the sodium ions. This is however not the case when – as is usually the case with foodstuffs containing sodium – additional compounds containing sodium are also present in the margarine. The use of potassium chloride as a partial replacement for sodium chloride in some formulations is an additional source of error.The direct titration of sodium by means of thermometric endpoint titration (TET) eliminates these problems. TET is a direct determination method that not only takes into account the entire sodium content present in the solution but is also not hampered by the presence of potassium ions. In addition to this application note, you can find more information on thermometric sodium determination in foods in our application video available on YouTube:https://youtu.be/lnCp9jBxoEs

This application note describes the determination of the total sodium content in soy milk products. The methodology may also be applied to the determination of sodium in milk products from cows, goats and sheep. A standard addition technique is employed to permit the accurate and precise determination of sodium at relatively low levels.

Silver and nitric acid are determined in silver electrolyte solutions by means of thermometric titration. The method provides accurate results in a short time and is ideally suited for routine process control.

This Application Note describes the determination of aluminum in samples containing silicon dioxide using thermometric titration and EDTA as the titrant. Excess EDTA is titrated with a Cu2+ solution of known concentration. The initial, uncomplexed Cu2+ ions react immediately with the H2O2 present in the solution, leading to a recognizable sudden increase in temperature.

This Application Note looks at the determination of ferrous ion in acidic solutions through redox titration with potassium permanganate as titrant and thermometric titration.

Weak, organic bases that are soluble in nonaqueous solvents (including nonpolar solvents) are determined in glacial acetic acid using titration with strong acids, e. g., anhydrous perchloric acid or trifluoromethanesulfonic acid. The endpoint of such titrations can be determined thermometrically, insofar as a suitable thermometric endpoint indicator exists. The exceptional suitability of isobutyl vinyl ether (IBVE) as indicator has been demonstrated.

This Application Note describes the determination of nitrite using thermometric endpoint titration with sulfamic acid. The nitrite content of a solution can be analyzed down to 0.2 mmol/L.

This Application Note describes in detail how to determine the blank value and the titer for thermometric titrations using tiamo™.

Hydrogen peroxide solutions can be determined through thermometric endpoint titration (TET) using iodometry. Iodide is oxidized to become iodine, which is then titrated with a standard thiosulfate solution in an exothermic reaction.

Sodium can be determined thermometrically in cheese without sample preparation and addition of additives. A homogenizer is responsible for distribution and stirring. In addition to this application note, you can find more information on thermometric sodium determination in foods in our application video available on YouTube:https://youtu.be/lnCp9jBxoEs

Thermometric titration can be used for the ready determination of sulfuric acid and phosphoric acid in acid mixtures. An endpoint for each acid appears on the titration curve that can be used to quantify the respective acid.

Thermometric titration is used for the determination of hydrochloric acid and phosphoric acid in acid mixtures. Two endpoints appear on the titration curve that are used for the determination of the two acids.

Thermometric titration is used for the determination of hydrochloric acid and nitric acid in acid baths. The entire acid content is titrated with caustic soda in the initial titration; the hydrochloric acid content is then determined in a second titration using silver nitrate solution.

Thermometric titration is used to determine hydrochloric acid and hydrofluoric acid (hydrogen fluoride) in etching baths containing ethanol and acetonitrile. Two endpoints appear on the titration curve that are used individually for the quantification of the respective acid.

Thermometric titration is used to determine hydrofluoric acid and nitric acid in etching baths containing ethanol and acetonitrile. Two endpoints appear on the titration curve that are used individually for the quantification of the respective acid.

Following the addition of caustic soda, hexafluorosilic acid can be determined through back titration of excess hydroxide with hydrochloric acid. Hydrofluoric acid (hydrogen fluoride) is determined by precipitation with aluminum in the presence of sodium and potassium ions. Nitric acid is determined by subtracting the equivalence concentrations of hexafluorosilic acid and hydrofluoric acid from the total acid concentration.

Nitric acid, phosphoric acid, and acetic acid are easily determined in etching baths using thermometric titration (TET). Compared to potentiometric titration, TET is faster and more convenient. Analysis is complete in less than two minutes.

Thermometric titration can determine the total acid number (TAN) of various crude oil products according to ASTM D8045 without requiring any sensor maintenance.

Metal-organic compounds are commonly used in organic chemistry, for example as Grignard reagents or as strong bases (e.g., butyl lithium compounds). The knowledge of the exact content of reactive species allows to better plan the required amounts for reactions preventing the waste of material or too low yields.This Application Note describes the analysis of metal organics by thermometric titration using 2-butanol as titrant. Due to the strongly exothermic nature of the reaction between 2-butanol with metal-organic compounds, a fast and quantitative analysis of these substances is possible.

Tartaric Sulfuric Anodizing (TSA) is an established technique for corrosion protection in the aerospace industry. It is an alternative to the environmentally harmful chromic anodizing process. As such, a method to monitor the levels of sulfuric acid and tartaric acid in TSA plating baths is required. Potentiometric titration methods have been developed, and are widely used across the industry. Their disadvantage is that two titrations with different electrodes and solvents are required.In this Application Note, an alternative method is presented, where the concentration of both acids is determined in sequence using a thermometric sensor. Compared to potentiometric titration, thermometric titration is faster and more convenient (no sensor maintenance required). On a fully automated system, the determination of both parameters takes about 7 minutes.

Iron sucrose injections are used during the treatment of iron deficiency anemia. They contain a mixture of ferric iron (Fe3+) and ferrous iron (Fe2+). Ferrous iron content may be determined by subtracting the ferric iron content from the total determined iron content. Yet, this increases the measurement error due to error propagation. Alternative determination of iron(II) with cerium(IV) by potentiometric titration may be hampered, as the equivalence point cannot be determined unequivocally. Determination by thermometric titration is a more robust and therefore more reliable alternative, as this method is unaffected by the sample matrix. Here, the endpoint of the titration is indicated by a fast responding thermometric sensor. Endpoint detection is further improved by spiking the sample with 0.2% ammonium iron(II) sulfate (FAS), increasing the reliability of the determination. Compared to potentiometric titration, thermometric titration is faster and more convenient as no sensor maintenance is required. One determination takes about 2–3 minutes.

Sulfur is a secondary macronutrient for plants and is essential for chloroplast growth and function. In fertilizers, sulfur is usually provided in the form of sulfate. Traditionally the sulfate content is determined gravimetrically by precipitation with barium. The drawback of this method is that it requires numerous time consuming and laborious analysis steps.In this Application Note, an alternative method is presented, where sulfate is determined by a precipitation titration with barium chloride. Various solid and liquid NPK fertilizers with sulfur contents between 1 and 8% were analyzed. The analysis of sulfate in fertilizers by thermometric titration requires no sample preparation at all for liquid NPK fertilizers, and only minimal sample preparation for solid NPK fertilizers. One determination takes about 3 minutes only. To increase the sensitivity of the method, the samples are spiked with a standard sulfuric acid solution, which is then considered when calculating the result.

Fertilizers are applied in the agricultural sector to provide more essential nutrients to growing plants. The so-called «NPK» fertilizers provide such nutrients to plants with its three main components (N – nitrogen, P – phosphorous, K – potassium). In fertilizers, nitrogen is mainly provided in three forms: as ammonium nitrate (NH4NO3), ammonia (NH3), and urea (H2NCONH2). Determination of the individual nitrogen-contributing components is often laborious work. Thermometric titration offers the possibility to rapidly determine the amount of ammoniacal nitrogen and urea nitrogen in a single titration using sodium hypochlorite as titrant.

Potassium is a primary macronutrient for plants, as it plays an important role in water regulation as well as plant growth. In NPK fertilizers, potassium is present besides nitrogen and phosphorus, which are the other two primary macronutrients. Knowing the quality and content of a NPK fertilizer allows an optimal fertilizer management for a planned culture, saving costs and increasing profitability.Traditionally potassium is determined gravimetrically or by flame photometry. In this Application Note, an alternative method is presented, where potassium is determined a precipitation titration. Various solid and liquid NPK fertilizers with potassium contents between 10 and 27% were analyzed. After the removal of any present ammonia, the potassium can be determined reliably in about 5 minutes.

Potash is commonly mined from ore, deposited after ancient inland oceans evaporated. The potassium salt is then purified in evaporation ponds. At the end of this process, the potash is typically obtained as potassium chloride. Potash is mainly used as fertilizer, providing potassium—an essential nutrient—to plants. Additionally, it is used in the chemical industry and to produce medicine. Potassium content in potash is typically determined by flame photometry (F-AES) or ICP-OES. However, these techniques have high investment and running costs. By applying the historically used gravimetric precipitation reaction as a thermometric titration, it becomes possible to rapidly and inexpensively determine the potassium content in potash within minutes.

Fluoride protects dental enamel and is an important trace element in toothpaste. A rapid and precise determination is made via standard addition with the help of an ion-selective fluoride electrode (F-ISE).

Determination of ammonia (ammonium) in distilled water by direct potentiometry using the NH3-ISE.

Determination of nitrate in a copper plating bath after conversion of nitrate to ammonium. Direct potentiometric measurement using the NH3-ISE.

Determination of fluoride in a chromium plating bath by direct potentiometry using the F-ISE.

Determination of chloride in water by direct potentiometry using the Cl-ISE.

Determination of fluoride in cement or clinker by direct potentiometry with the F-ISE.

Determination of sulfide in wastewater by direct potentiometry with the Ag/S ion-selective electrode.

Cyanides are used in some industrial processes, but if not handled carefully, they could contaminate the wastewater. In an acidic or neutral environment, this contaminated wastewater can form highly toxic hydrogen cyanide gas. Furthermore, the cyanide salts could also poison the environment and enter the ground water system. Therefore, it is essential to monitor the content of cyanide in effluent water. Cyanides can be easily determined with a cyanide ion-selective electrode. This application note presents a method for cyanide analysis according to APHA Method 4500-CN and ASTM D2036.

Nitrate is present in all common agricultural products and due to an extensive use of fertilizers, the nitrate content can be disconcertingly high in vegetables and their fabricated products, like juices. The nitrate content is regulated in many countries because it can form nitrosamines within the human body. Nitrosamines can potentially cause cancer and therefore, the World Health Organization (WHO) has defined an accepted daily intake (ADI) for nitrate of 3.7 mg/kg. To control the nitrate content e.g., in juices, a quick and inexpensive assessment of its concentration is performed via standard addition with a nitrate ion selective electrode . The method can be automated and is faster and less expensive compared to competing chromatographic or spectroscopic methods.

Fluoride content in drinking water can be determined quickly and conveniently with the help of potentiometric titration and the ion-selective fluoride electrode (F-ISE). The F-ISE is calibrated with suitable standard solutions before the measurement.

Ammonia determination via NH3 ISE requires precise calibration. Details on this are provided by the present Application Note.

Even in low concentration, sulfide ions cause odor and corrosion problems in ground water and waste water. They can release hydrogen sulfide in acidified water, which is toxic in even minuscule amounts. This Application Note describes the determination of sulfide concentration in water via direct measurement with the Ag/S-ISE in accordance with ASTM D4658.

Bromide is ubiquitous in sea water, where it is present in concentrations of around 65 mg/L. By contrast, the maximum bromide concentration in drinking and ground water is usually less than 0.5 mg/L. A higher bromide content may indicate a contamination of the water caused by fertilizer, road salt or industrial waste water. This Application Note describes the determination of the bromide content in water via direct measurement with a Br ion-selective electrode in accordance with ASTM D1246.

In the synthesis of certain dyes, sodium chloride is a byproduct. The content of chloride is therefore an important parameter. This Application Note describes the determination of the chloride content in dye by standard addition using a Cl- ion-selective electrode.

Determination of the potassium content plays a major role in the food and beverage industry. Potassium is an essential mineral nutrient for humans. It is an important intracellular cation and also plays an important role in processes withincells, where it is involved in the regulation of numerous body functions like blood pressure, cell growth and muscle control.To declare the potassium content of drinks and food, it is usually determined by flame photometric method. However, flame photometry is linear only over a limited concentration range, and often sample dilution is necessary. Furthermore, the instrumentation is rather complex and expensive to buy and maintain. The ion measurement method presented here is a fast, less expensive, and reliable alternative to determine potassium content in beverages.

The determination of the potassium content in foodstuffs plays a major role in the food and dietary supplement industry, as potassium is an essential mineral nutrient for humans. It is an important intracellular cation and also plays a important role in processes within cells, where it is involved in the regulation of numerous body functions like blood pressure, cell growth and muscle control.As a dietary supplement, potassium is present in e.g., electrolyte powder, electrolyte drinks and food supplements. To quantify the potassium content in such products, e.g. flame photometry can be used. In this work, an alternative, ion measurement by standard addition, is described, which is fast, inexpensive and simple to use.

As nitrogen is essential nutrient for plants, it is an essential constituent of many fertilizers. It is present there in different forms, mainly as ammonium or nitrate. Knowing the nitrogen concentration and the form in which is present helps to select the right fertilizer for the plants. For producers of fertilizers, it is therefore necessary to indicate the concentration of ammonium nitrogen in their product.This Application Note shows how to determine ammonium in liquid fertilizers by means of a standard addition.

Nitrogen is essential for plant growth. In soil, it can be present in the form of nitrate, ammonium, or urea. Knowing the nitrogen content of soil and in which form it is present helps selecting the right kind of fertilizer to stimulate plant growth.This Application Note shows a fast and reliable way to determine the ammonium concentration in soil by using standard addition.

NPK fertilizers are mainly comprised of three primary nutrients required for a healthy plant growth (nitrogen, phosphorous, potassium). They are available as liquid, or granular form, whereof the last is the most common used one. Knowing the quality and content of a fertilizer allows an optimal utilization for a planned culture and optimizing the amount of used fertilizer. This helps to reduce costs and to improve plant growth and with it, a better harvest follows.To assess potassium, several methods like flame photometry, titration, or ion measurement can be used. In this work, the potassium content is measured by standard addition which is a fast, inexpensive, and easy to use method.

To assess the quality of a soil it is necessary to know its nutrients. For example, it is necessary that the level of bio-available ions is known as a deficiency might negatively affect plant growth. One of the most important ions is potassiumwhich is directly absorbed in its ionic form by plants roots. It is an essential nutrient and required for proper growth and reproduction.One commonly used method to assess the K content is the extraction of phosphorous and potassium from soil with an acidic, to pH 4.1 buffered solution of calcium acetate, calcium lactate, and glacial acetic acid. This test is called calcium acetate lactate test (CAL-test). Commonly, the extract is analyzed by flame photometric method. In this application note we present a fast and inexpensive alternative using the potassium ion selective electrode.

Potassium is naturally occurring in surface water caused by weathering of stones and soil. As potassium in drinking water is regulated and should not exceed a certain threshold value, it is necessary to assess the potassium concentration.This can easily be done by direct measurement using a potassium selective electrode. First, a calibration is performed, afterwards, the samples are measured within tens of seconds. This is a fast, inexpensive and reliable method to determine the potassium content in various water samples.

One of the major sources of fluoride intake for humans comes from foodstuff, such as tea. Tea actually has one of the highest potentials to increase the daily fluoride intake. Excessive fluoride intake may lead to dental or skeletal fluorosis. The World Health Organization does not recommend consuming water with a fluoride content higher than 1.5 mg/L. In the presented method according to DIN 10807, the fluoride content can be assessed quickly with an ion selective electrode.

Nitrate is naturally present in the environment. However, excessive concentrations of nitrate in surface and ground water are problematic as such concentrations have a negative effect on the water quality. Usually, excessive levels of nitrate area direct result of extensive usage of fertilizers in agriculture. Nitrate is easily washed from soils and can end up in surface or ground water. As the nitrate content is regulated in many countries, a quick and inexpensive assessment of its concentration is required to monitor the water quality.The nitrate concentration can easily be obtained by direct measurement using a nitrate ion selective electrode. First, a calibration is performed, afterwards, the samples are measured in less than a minute.This is a fast, inexpensive and reliable method to determine the nitrate content in various water samples.

Lucigenin is one of the most often used chemiluminescent reagents and might be used for e.g., the indication of the presence of superoxide anion radicals.Lucigenin is rather expensive to buy, however, its synthesis only includes a two stage synthesis starting from acridanone. The first stage includes an Nmethylation, the second forms the lucigenin chloride, which is finally transformed into lucigenin nitrate. To check the purity of the synthesized lucigenin, ion measurement can be applied using a nitrate selective electrode. This is a fast and inexpensive method compared to competing methods such as ion chromatography.

Increased fluoride concentrations in water may cause tooth damage, growth disorders, and bone deformation. According to the World Health Organization (WHO), concentrations above 1.5 mg/L are critical.One possible source of fluoride is landfills. Rain washes out harmful substances from landfills which can enter the groundwater. The leachate from landfills should thus be monitored for the fluoride concentration.Ion measurement is a fast and inexpensive method to determine the fluoride content in water samples compared to other methods such as ion chromatography. This Application Note describes a reproducible and accurate measurement of the fluoride content using the fluoride ion-selective electrode with an OMNIS system.

Dissolved oxygen (DO), incorporated into juices during processing, affects quality parameters of the beverage during storage such as Vitamin C concentration, color, and aroma. Various oxygen removal methods are used during juice production, such as vacuum-deaeration or gas sparging to increase product quality and extend shelf life. However, these methods have the drawback that the aroma might be affected since the volatile compounds are also removed. By assessing the DO content in fruit juices, manufacturers can improve the overall product quality. This application note describes a fast and accurate determination of dissolved oxygen in juices by using an optical sensor.

Oxygen diffuses into water sources from the air via aeration, however several factors can reduce the dissolved oxygen (DO) content in water. First, as water warms up, oxygen is released into the atmosphere. Secondly, oxygen is consumed by bacteria and other microorganisms which feed on organic material. Finally, plants can also consume oxygen in certain situations.Human-induced alterations can have a negative influence on surface water when DO values fall below crucial limits for maintaining the life supporting capacity of freshwater ecosystems. Therefore, monitoring the DO content in surface water by an optical sensor to assess its quality is important.

Dissolved oxygen (DO) is generally considered detrimental to wine quality, especially if introduced after fermentation, storage, or bottling. The presence of oxygen after primary fermentation and during the later stages of winemaking can enhance browning reactions, chemical and microbiological instability, and the formation of off-flavors such as acetaldehyde. Knowing the DO content in wine is important through the entire wine production process, because oxidation is a common fault in bottled wines. With the 913 pH/DO meter and the 914 pH/DO/Conductometer, the oxygen content of wine can be determined quickly and easily directly on site.

In municipal water supplies, higher dissolved oxygen (DO) content is desirable because it improves the taste of drinking water. However, high DO levels also speed up corrosion in water pipes. For this reason, industries utilize water with as little DO as possible, and add scavengers such as sodium sulfite to remove any oxygen from a water supply. Municipal water supply pipes are normally coated inside with polyphosphates to protect the metal from contact with oxygen, thus allowing higher DO contents. Therefore, monitoring the DO content online in a water supply is important to assess its DO content to either improve taste or minimize pipe corrosion. Using an optical sensor, such as the O2-Lumitrode, allows a fast and reliable determination according to ISO 17289.

Acrylic dispersion paints are made of pigment suspended in acrylic polymer emulsions, which also include other organic material such as plasticizers, defoamers, or stabilizers. Acrylic dispersion paints are water-soluble but become resistant to water when dry. Due to the fact that once dry, acrylic dispersion paints can no longer be used, they should be stored air-tight at room temperature. For research purposes, it is of interest to assess the dissolved oxygen (DO) concentration in such samples as it is assumed that the DO amount can be related to the storage life. This Application Note describes a fast and accurate determination of dissolved oxygen by using an optical sensor.

In the food industry, it is essential to determine and monitor certain quality parameters to guarantee consistency. This is especially important for liquid dairy products, which are subject to a strict cold chain. Both the dissolved oxygen (DO) and the pH value have proven to be reliable quality criteria. Oxygen shortens the shelf life and influences the product quality (e.g., nutritional value, color, and flavor). The DO content depends on the salinity in the sample, which is automatically calculated and corrected by the 914 pH/DO/Conductometer during the parallel conductivity measurement. Acidity is another important characteristic to measure that can be checked easily using the pH value. With the 914 pH/DO/Conductometer, all important quality criteria can be monitored with one device.

This Application Note offers an easy way to determine the ammonia content in cacao nibs by using ion measurement, applying the standard addition technique in a reliable cost- and time-saving manner.

This Application Note covers the formation of calcium carbonate from solution.

Excess sodium intake increases the risk of health issues. Ion-selective electrodes (ISEs) offer a fast, accurate, and cost-effective method for measuring sodium in food.

Groundwater contains many minerals, but can be contaminated by sodium-rich leachate from landfills. Accurate Na determination in water is possible following AOAC 976.25 using the Na-ISE.

The water content of potassium chlorate is determined according to Karl Fischer using the oven method (300 °C).

The water content of methyl ethyl ketone peroxide is determined according to Karl Fischer using two-component reagents in order to prevent unwanted side reactions. (Separate solvent is used to ensure a high excess of sulphur dioxide and amine in the titration vessel.)

The water content of ammonium and potassium peroxodisulphate is determined according to Karl Fischer using two-component reagents. To prevent unwanted side reactions the determinations are carried out at -20 °C. Because the potassium salt is insoluble in the solvent, a high-frequency homogenizer is used to disintegrate the salt particles.

The water content of lyophilisates contained in vials is determined by Karl Fischer titration. Conditioned solvent (methanol) is injected into the vial to dissolve the sample and extract the water (ultrasonic bath). Afterwards the contents of the vial are transferred to the titration vessel to carry out the automatic determination.

Determination of water content in ink is possible with Karl Fischer titration, as shown in this Application Note.

The water content of ointments is determined according to Karl Fischer. Because of their high water and fat content, the samples are prediluted with a 1:1 mixture of chloroform and methanol.

The water content of yoghurt powder is determined according to Karl Fischer. Because of the relatively high water and fat content, the sample is prediluted with a 1:1 mixture of chloroform and methanol.

The water content of plastic chips is determined according to Karl Fischer. Because of the low water content of the sample, the oven method (200 °C) and coulometric titration have to be used.

The water content of explosive pellets is determined according to Karl Fischer after extraction with methanol.

The water content of coal dust is determined according to Karl Fischer. Because of the low water content of the voluminous sample, the oven method (nitrogen, 270 °C) and coulometric titration have to be used.

The water content of moisturising creams is determined according to Karl Fischer. Because of their high water content, the samples are first mixed and prediluted with dry methanol.

The water content of turbine oil is determined according to Karl Fischer. Because of the low water content of the sample, coulometric titration is used.

The water content of organic peroxides is determined according to Karl Fischer using two-component reagents. To prevent any unwanted side reactions, the determinations are carried out at -20 °C.

The water content of diesel fuel and petrol (gasoline) is determined according to Karl Fischer. Because of the low water content, the determinations are carried out by coulometric titration.

The water content of sweet liquorice is determined according to Karl Fischer. To dissolve the sample, a mixture of methanol and formamide is used as solvent and a high-frequency homogenizer as stirring device.

The water content of lemongrass oil is determined according to Karl Fischer. To prevent unwanted side reactions, special KF reagents for aldehydes and ketones are used and the determination is carried out at 0 ... 4 °C.

The presence of water in expandable polystyrene (EPS) can have a negative impact on the thermal insulation properties, as it increases thermal conductivity. If EPS is exposed to a high moisture environment, additional water may be absorbed, which can further affect thermal insulation.Direct analysis of the moisture content by Karl Fischer titration requires the water to be extracted from the EPS, which involves several time-consuming steps. Therefore, determination of the water content with an oven system is preferred. As EPS expands when heated, the use of sample boats, as required by ASTM D6869, is not possible, as the EPS will contaminate the oven system. This Application Note describes the determination of water content in EPS using an oven system with closed sample vials. A determination takes about 7 to 14 min depending on the water content of the sample and the sample size.

The water content of cyclopropyl methyl ketone is determined according to Karl Fischer by coulometric titration using special reagents for aldehydes and ketones.

In this application note, Karl Fischer titration is used to determine the water content of urea.

The water content of flour is determined according to Karl Fischer. To shorten the analysis times and to obtain more precise results, the determinations are carried out at 50 °C.

The water content of animal fat extract is determined according to Karl Fischer.

This Application Note describes the determination of water content in pesticides using Karl Fischer titration.

The water content of ethylene dichloride is determined according to Karl Fischer. As the sample may contain free chlorine, which interferes with the determination, separate KF reagents have to be used.

The water content of smoked salmon and smoked trout is determined according to Karl Fischer.

The water content of potato chips is determined according to Karl Fischer using the oven method (140 °C).

The water content of used lubricating oil is determined according to Karl Fischer by coulometric titration. To prevent unwanted side reactions special KF reagents are used.

The water content of lime is determined according to Karl Fischer using the oven method (150 °C).

The water content of color paste is determined according to Karl Fischer.

The water content of spices is determined according to Karl Fischer. To release the water from the cells, a high-frequency homogenizer has to be used.

The water content of bismuth subnitrate is determined according to Karl Fischer.

The water content of 2-methyl-1,3-butadiene and 2,5-norbornadiene is determined according to Karl Fischer using a special solvent mixture to prevent unwanted side reactions.

The water content of acetophenone and benzophenone is determined according to Karl Fischer using special KF reagents for ketones/aldehydes to prevent unwanted side reactions.

The water content of piperidine and piperazine is determined according to Karl Fischer using a buffered solvent mixture.

The water content of melamine is determined according to Karl Fischer in a buffered solvent mixture at 50 °C.

The water content of beta-caprolactam is determined according to Karl Fischer.

The water content of vinyl chloride is determined according to Karl Fischer.

The water content of 2-methyl-5-mercaptothiadiazole is determined according to Karl Fischer using a special solvent mixture to prevent unwanted side reactions.

Karl Fischer titration can be used to determine the water content in N-acetyl-L-cysteine. Special solvent mixtures can be used to prevent unwanted side reactions in the Karl Fischer titration. The water content of N-acetyl-L-cysteine can thus be determined quickly and accurately, as is shown in this Application Note.

This application note describes the water content determination in penicillin by using volumetric Karl Fischer titration. Unwanted side reactions can be avoided by using special solvent mixtures.

The water content of margarine is determined according to Karl Fischer.

Determination of the water content of liquid ammonia according to Karl Fischer after absorption of the water in ethylene glycol.

The water content of silicone oil is determined according to Karl Fischer by coulometric titration.

The water content of aniline is determined according to Karl Fischer in buffered solvent.

The water content in panthenol is determined according to Karl Fischer.

The water content in methylcyclohexane is determined by coulometric Karl Fischer titration.

The water content in Ca carbonate is determined by volumetric Karl Fischer titration.