Applikationer

The simultaneous ion chromatographic determination of trace-levels of lanthanides (or lanthanoides) was achieved by using either direct non-suppressed conductivity detection or UV/VIS detection after post-column reaction (PCR) with arsenazo III at 655 nm. Conductivity detection under isocratic conditions resulted in an overall analysis time of approx. 70 minutes. In contrast, the determination of the lanthanides via gradient elution and subsequent spectrophotometric detection of the arsenazo III-lanthanide(III) complexes was performed within 22 minutes. Besides the outstanding analysis time, UV/VIS detection excelled by its enhanced selectivity and sensitivity and did not suffer from interferences by ubiquitous non-lanthanide impurities such as iron(III) or other transition metals. For both conductivity and spectrophotometric detection, the inclusion of sample preconcentration steps lowered the limit of detection (LOD) to the sub-ppb range.

Commercially available fuels are complex mixtures of hundreds of different hydrocarbons. For the calibration of the test engines or advanced experimental and computational research they are modeled by means of multicomponent surrogate mixtures that adequately represent the desired physical and chemical characteristics. By definition, every octane and cetane number corresponds to a specific mixing ratio of primary reference fuels (PRFs). Based on this information, the tiamoTM controlled automatic dosing device prepares the surrogate mixtures. The setup drastically minimizes time-consuming and error-prone manual preparation steps and the contact with hazardous solvents. Additionally, precise and accurate results are displayed on customizable reports that fully comply with all current GLP and GMP requirements.

The thermometric titration method presented here permits a simple and direct determination of the total acid number (TAN) in petroleum products. It is an invaluable alternative to current manual and potentiometric methods. Thermometric titration uses a maintenance-free temperature sensor that does not require rehydration and is free of fouling and matrix effects. The procedure requires minimal sample preparation. Results agree closely with those from the potentiometric titrimetric procedure according to ASTM D664, but the thermometric titration method is far superior in terms of reproducibility and speed of analysis, with determinations being complete in approximately one minute.

The Combustion IC system presented allows the automated determination of organic halogen and sulfur compounds in all flammable samples. Both combustion digestion, which is automatically controlled with a flame sensor, and the professional Liquid Handling guarantee highest precision and trueness. This poster describes the determination of the halogen and sulfur content in a certified polymer standard, a coal reference material as well as in latex and vinyl gloves.

The determination of the lead content in engine fuels has gained considerable importance since the introduction of the catalytic converter technique. Even small contents of lead interfere with the effectiveness of the catalysts or may destroy them. On the other hand, there are still many vehicles on the roads which run on leaded fuel (addition of tetraalkyl lead). Here also the knowledge of the lead content is of interest.With reference to DIN 51769 and ASTM 0-1269 a simplified procedure for the determination of lead in petrochemical products is described. The products are digested with HCl and the lead compounds are converted to lead(II) chloride. After extraction with water, the inverse voltammetric Pb determination is carried out.

This Bulletin describes the potentiometric determination of hydrogen sulfide, carbonyl sulfide, and mercaptans in gaseous and liquid products of the oil industry (natural gas, liquefied petroleum gas, used absorption solutions, distillate fuels, aviation gasoline, gasoline, kerosene, etc.). The samples are titrated with alcoholic silver nitrate solution using the Ag Titrode.

The bromine number and bromine index are important quality control parameters for the determination of aliphatic C=Cdouble bonds in petroleum products. Both indices provide information on the content of substances that react withbromine. The difference between the two indices is that the bromine number indicates the consumption of bromine in gfor 100 g sample and the bromine index in mg for 100 g sample.This Application Bulletin describes the determination of the bromine number according to ASTM D1159, ISO 3839, BS2000-130, IP 130, GB/T 11135 and DIN-51774-1. The bromine index determination for aliphatic hydrocarbons is described according to ASTM D2710, IP 299, GB/T 11136 and DIN 51774-2. For aromatic hydrocarbons the determination of the bromine index is described according to ASTM D5776 and SH/T 1767. UOP 304 is not recommended for the determination of the bromine number or bromine index because its titration solvent contains mercuric chloride.

Only coulometric Karl Fischer titration can determine low water contents with sufficient accuracy.This Application Bulletin describes the direct determination according to ASTM D6304, ASTM E1064, ASTM D1533, ASTM D3401, ASTM D4928, EN IEC 60814, EN ISO 12937, ISO 10337, DIN 51777, and GB/T 11146. The oven technique is described according to ASTM D6304, EN IEC 60814, and DIN 51777.

Generally speaking, the gas extraction or oven method can be used for all samples which release their water when they are heated up. The oven method is indispensable in cases in which the direct volumetric or coulometric Karl Fischer titration is not possible, either because the sample contains disruptive components or because the consistency of the sample makes it very difficult or even impossible to transfer it into the titration vessel.The present Application Bulletin describes automatic water content determination with the aid of the oven technique and coulometric KF titration, using samples from the food, plastic, pharmaceutical and petrochemical industry.

The determination of the acid number plays a significant role in the analysis of petroleum products. This is manifested in the numerous standard procedures in use over the world (internal specifications of multinational companies, national and international specifications of ASTM, DIN, IP, ISO, etc.). These procedures differ mainly in the composition of the used solvents and titrants.This bulletin describes the determination of the acid number in petroleum products by applying different types of titration.The potentiometric determination is described according to ASTM D664, the photometric according to ASTM D974 and the thermometric titration according to ASTM D8045.

This Application Bulletin shows the determination of the total base number in petroleum products by applying different titration types according to various standards.

Natural liquefied petroleum gas (LPG) is a mixture of hydrocarbon gases (e.g. propane and butane), but it also contains acidic contaminants (e.g. carbon dioxide or hydrogen sulfide). These gases need to be scrubbed from the petroleum gas as they are highly corrosive. This purification step, referred to as «sweetening», is often performed by using alkaline amine solutions. Thereby the amine solution absorbs the acidic gases, while the raw LPG is neutralized. To guarantee that amine residues in the sweetened gas do not influence the gas quality, the amines in the final LPG are determined by scrubbing the gas with acetic acid as described in UOP 936-96. The recent method enables the quantification of the amines dimethylamine (DMA), diethylamine (DEA), dipropylamine (DPA), and dibutylamine (DBA) by separation from standard cations.

The burning of coal contaminates the atmosphere with halogens. Fluorine and chlorine are natural components of coal, whereas the bromide that is found therein is often adulterated as calcium bromide in order to reduce mercury emissions. This Application Note shows the results of combustion digestion with Combustion IC for three coal samples, each with a different bromide content.Keyword: pyrohydrolysis

This Note addresses the determination of the fluorine and chlorine content of a liquefied gas sample (LPG, Liquid Petroleum Gas), i.e. halogens in a mixture of propane and butane. Fluorine originates from perfluorobutane and chlorine from methyl chloride. LPG/GSS modules are used to introduce 50 µL of sample into the combustion system. The halogens released during combustion are determined using ion chromatography with intelligent partial loop injection technique following Inline Matrix Elimination.Keyword: pyrohydrolysis

Coal contains a certain amount of fluorine, chlorine, and sulfur compounds. During combustion of the coal, these components release corrosive acids (e.g., fluorine compounds form hydrofluoric acid). Thermal power plants therefore request low-fluorine coal to avoid massive hydrofluoric acid production. In this application note, fluorine content in coal is determined by ion chromatography after pyrohydrolysis.

ASTM D7994 - 17 describes the determination of fluorine, chlorine, and sulfur in liquefied petroleum gas (LPG) by oxidative pyrohydrolytic combustion followed by ion chromatography. A synthetic butane sample is analyzed. 50 µL of the sample is injected into the combustion system using the LPG Module. The combustion products are analyzed by IC applying intelligent Partial Loop Injection Technique after Inline Matrix Elimination.

The content of organic chloride in crude oil is determined according to ASTM D8150 in the naphtha fraction after distillation. The naphtha fraction is washed with caustic and water, respectively, to remove hydrogen sulfide and inorganic halides. Here, the determination of organic chloride after inline combustion is presented. Although the sulfur content was of no interest in this application, the same setup allows sulfur quantification.

Crude oil typically contains no organic halides. These are introduced at production sites, in pipelines, or in storage tanks. These components produce HF, HCl, and other acids in reforming and hydro-treating processes, leading to corrosion and catalyst poisoning. Speciation of the halides is an important parameter to measure in order to trace the contamination source. The current specifications expect to find less than 2 mg/kg organic chlorine in crude oil. Sulfur in crude oil could be quantified on the fly. Due to the specific request in this application, only the halogens are determined.

Organic halides must be monitored in the environment. Combustion ion chromatography (CIC) is used for accurate halogen analysis in solids following EN 17813:2023.

In the application note AN-EIS-004 on equivalent circuit models, an overview of the different circuit elements that are used to build an equivalent circuit model was given. After identifying a suitable model for the system under investigation, the next step in the data analysis is estimation of the model parameters. This is done by the non-linear regression of the model to the data. Most impedance systems come with a data-fitting program. In this application note, the way NOVA is uses to fit the data is shown.

In this application note, the advantage of recording the raw time domain data for each individual frequency during an electrochemical impedance measurement is described.

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.

Moisture in petroleum products causes several issues: corrosion and wear in pipelines and storage tanks, an increase in debris load resulting in diminished lubrication, blocked filters, or even harmful bacterial growth. As a result, increased water content can lead to infrastructure damage, higher maintenance costs, or even unwanted downtimes.Coulometric Karl Fischer titration is the method of choice for low water content in petroleum products. Using a Karl Fischer oven to vaporize the water present in the sample prior to titration not only greatly reduces matrix interferences, it can also be fully automated. This allows a reliable and cost-efficient analysis of the water content according to ASTM D6304 (Procedure B) in products such as diesel, hydraulic oil, lubricant, additive, turbine oil, and base oil.

To determine water in crude oil, ASTM D4928 recommends coulometric Karl Fischer titration with the oven method, allowing full automation for high reproducibility.

Determination of anions in a Schoeniger absorption solution of a test mixture without decomposition of the H2O2 using anion chromatography with direct conductivity detection.

In recent years, there has been a significant push to reduce the environmental impacts of fuels through improvements to fuel quality. The determination of key quality parameters of gasoline, namely research octane number (RON, ASTM D2699-19), motor octane number (MON, ASTM D2700-19), anti knock index (AKI), aromatic content (ASTM D5769-15), and density, conventionally requires several different analytical methods, which are laborious and need trained personnel. This application note demonstrates that the XDS RapidLiquid Analyzer, operating in the visible and near-infrared spectral region (Vis-NIR), provides a cost-efficient and fast solution for the multiparameter analysis of gasoline.

Pyrolysis gasoline (Pygas) is a by-product of ethylene production, which contains unwanted conjugated diolefins making it unsuitable as a motor fuel. To overcome this limitation, the olefin content needs to be reduced below 2 mg/g pygas in a selective hydrogenation unit (SHU). The diene value, or maleic anhydride value (MAV), is usually determined by the lengthy Diels-Alder wet chemical method (UOP326-17), requiring highly trained analysts. In contrast to the primary method, near-infrared spectroscopy (NIRS) is a cost-efficient and fast analytic solution for the determination of diene value in pyrolysis gasoline.

This Application Note describes the determination of various indices (mainly with ASTM and ISO conformance) for the characterization of kerosene as aviation turbine fuel using near-infrared spectroscopy. The following parameters were determined with the aid of an NIRS XDS Process Analyzer: degree of density in accordance with the American Petroleum Institute (API), aromatics content, Cetane Index, distillation characteristics pursuant to ASTM D86, flash point, freezing point, viscosity and hydrogen content. All of these parameters are determined quickly and easily with just a single measurement.

This Application Note shows that visible near-infrared spectroscopy (Vis-NIRS) can determine water content in ethanol-hydrocarbon blends. Vis-NIRS is a fast alternative to conventional lab methods: it accelerates raw material inspection, process monitoring, and final product control.

The cetane index (ASTM D613), flash point (ASTM D56), cold filter plug point (CFPP) (ASTM D6371), D95 (ISO 3405), and viscosity at 40°C (ISO 3104) are key parameters to determine for diesel quality. The primary test methods are labor intensive and challenging due to the need to use different analytical methods. This application note demonstrates that the NIRS XDS RapidLiquid Analyzer provides a cost-efficient and fast solution (under 1 minute) for the simultaneous determination of these key parameters in diesel.

The quality control of diesel exhaust fluids (DEF) is key to ensure the optimal catalytic performance and prevent damage to the exhaust system in diesel vehicles. The standard method to determine urea content is measuring the refractive index (ISO 22241-2:2019). The issue is that although this method is fast, it is not as accurate as other methods (e.g., HPLC). This application note demonstrates that the DS2500 Liquid Analyzer provides a fast solution with high accuracy for the determination of urea in DEF. With no sample preparation or chemicals needed, visible near infrared (Vis-NIR) spectroscopy allows for the analysis of diesel exhaust fluids in less than a minute.

This application note presents near-infrared spectroscopy (NIRS) as an alternative for bromine number determination in pyrolysis gasoline.

This Application Note highlights near-infrared spectroscopy as a faster, cost-effective alternative to KF titration for predicting water content in diesel fuel.

The standard method to determine RON in isomerate is with expensive and maintenance-intensive engines. In contrast to this, the research octane number can also be analyzed by near-infrared spectroscopy (NIRS). NIRS provides accurate results within one minute without the need for any sample preparation or chemicals.

The determination of key quality parameters of reformate—namely research octane number (RON, ASTM D2699-19), aromatic content (ASTM D5769-15), benzene content, olefin content, and density—requires time-consuming and laborious conventional methods. In contrast, the Metrohm DS2500 Liquid Analyzer can measure all of these parameters, providing results within one minute without any sample preparation.

Determination of the biodiesel content in diesel with NIR spectroscopy is fast and requires no sample preparation nor chemicals, reducing workload and costs.

Automated online analysis with the 2060 TI Ex Proof Process Analyzer facilitates constant monitoring of the crude oil desalting process according to ASTM D3230.

Online mercaptan and H₂S monitoring with the 2060 TI Ex Proof Analyzer certified for Zone-1 and Zone-2 areas.

Online acid number analysis in various oil products is possible with thermometric catalytic titration according to ASTM D8045 using the 2060 TI Ex Proof Process Analyzer.

A safer way to monitor moisture content in crude distillation unit overhead fractions is with inline near-infrared spectroscopy using the 2060 The NIR-Ex Analyzer.

In refineries, high octane products are desired since they are used to produce premium gasoline. Catalytic reforming converts heavy naphtha into a high octane liquid product called reformate (a mixture of aromatics and iso-paraffins C7 to C10). The reformate must be constantly monitored to ensure high throughput along the refining process. Traditionally, the octane numbers can be measured by two different methodologies: Inferred Octane Models (IOM) and laboratory octane engine analysis. However, these do not provide «real-time» results and require constant maintenance and human intervention to adapt to current operation conditions. «Real-time» analysis of the octane number in fuels can be performed online via near-infrared spectroscopy (NIRS) technology, which fits well within the international standards (ASTM). Utilization of a Metrohm Process Analytics NIRS XDS Process Analyzer (ATEX version) in conjunction with a sample preconditioning system makes analysis of the octane number simple, fast, and reliable, allowing quick adjustments to the process for a better quality product and higher profitability.

In this Application Note, the 893 Professional Biodiesel Rancimat measures the oxidation stability of biodiesel (or fatty acid methyl esters, FAME), an eco-friendly fuel.

Sustainable biodiesel can be blended with petroleum diesel. The 893 Professional Biodiesel Rancimat measures the oxidation stability of biodiesel and its blends.

Mercaptans in fuels are corrosive and regulated at trace levels. SERS enhances Raman signals to enable their accurate detection and quantification below standard LODs.

Determination of chloride, nitrite, bromide, nitrate, phosphate, and sulfate in Schoeniger absorption solution using anion chromatography with conductivity detection after chemical suppression.

Determination of fluoride, acetate, formate, and chloride in gasoline using anion chromatography with conductivity detection after chemical suppression.

Determination of fluoride, acetate, formate, nitrate, and sulfate in a gasoline/bioethanol mixture (85% gasoline, 15% ethanol) using anion chromatography with conductivity detection after sequential suppression and Metrohm Inline Matrix Elimination.

Determination of fluoride, acetate, formate, chloride, nitrite, nitrate, phosphate and sulfate in an E85 mixture (85% ethanol and 15% gasoline) by means of anion chromatography with conductivity detection and sequential suppression. The Inline Matrix Elimination serves as sample preparation.

Formate, acetate, propionate, and butyrate in addition to standard anions are determined in a coal extract. To improve the separation of the early eluting organic acid anions, a Dose-in Gradient is applied. Due to the limited sample volume available, Metrohm intelligent Pick-up Technique (MiPuT) is also utilized.

Anions in diesel, especially biodiesel, may cause harmful deposits in the engine. Determination with ion chromatography requires the transfer of the diesel anions into an aqueous solution, injectable to the IC. A typical method to transfer the anions into water is via Inline Extraction with subsequent Inline Dialysis prior to the injection (see AN-C-101 for a respective analysis of cations). In the actual Matrix Elimination method, diesel diluted with isopropanol is injected into an isopropanol stream and passed through a preconcentration column. Isopropanol washes off the diesel, and a subsequent rinsing step with ultrapure water removes excess isopropanol.

Simultaneous determination of hydrogen sulfide and mercaptans in petroleum products by potentiometric titration with silver nitrate using the Ag-Titrode.

Determination of alkyllead compounds in petrol (gasoline) after reaction with iodine monochloride by potentiometric titration with EDTA using the Cu-ISE.

Automated mixing of a suspension and a solvent in a 50 mL dosing unit can be used to add a well-defined amount of a suspension-solvent mixture to a sample solution without clogging the dosing unit and tubing by the undiluted suspension.The method is explained by means of the TAN determination of a petroleum sample using thermometric titration. For a better endpoint recognition, small amounts of a paraformaldehyde-solvent suspension are added (catalyzed endpoint thermometric titration).

Fresh as well as used petroleum products may contain acidic components as additives or degradation products. The acid number (AN) is a measure for the relative amount of acids present expressed as mg KOH per g sample. Moreover, AN is used as a quality parameter of lubricating oils both for assessing the quality of new formulations and as an indicator for the degradation of such formulations during service. The use of a pH electrode suitable for non-aqueous titrations ensures the reliable determination of the equivalence point. A flexible sleeve diaphragm facilitates its cleaning especially after use in heavily contaminated samples, such as in used engine oils. Using the correct electrode greatly increases the precision and reliability of the results. This Application Note describes the potentiometric determination of the acid number according to ASTM D664 and IP 177 using the pH electrode Solvotrode easyClean.

Basic chemicals are added to petroleum products to prevent corrosion as they neutralize acidic components that form during the use and aging of these products. The base number (BN) gives an indication regarding the amount of these basic additives present, and it can be used as a measure for the degradation of the petroleum product.This Application Note describes the potentiometric determination of the base number according to ISO 3771, ASTM D2896, and IP 276 using the Metrohm Solvotrode easyClean and a fully automated OMNIS system.

Potentiometric titration with silver nitrate can be used for the determination of mercaptans in refinery products. This Application Note describes their automatic determination in a middle distillate sample (gas oil).

The bromine number is an important parameter for the determination of aliphatic C=C double bonds in petroleum products. The bromine number is usually determined using electrochemical titration at 5 °C, where the bromine is generated in situ from a bromide/bromate solution. For the titration, a solvent mixture of glacial acetic acid, methanol, and chloroform is used. In this Application Note, the toxic chloroform was replaced with diethyl carbonate.

The bromine number indicates the degree of unsaturation and relies on the simple addition of bromine to the double bonds of alkenes. One mole of bromine is consumed for each mole of carbon-carbon double (C=C) bond present in a substance. In petroleum products, the bromine number corresponds to the olefin content.Normally, chlorinated solvents are used for the determination of the bromine number. In this Application Note they have been replaced by toluene. This makes the determination more ecological. The titration is performed automatically on an OMNIS system in combination with a double Pt-wire electrode. With this setup, a fast and accurate determination by potentiometric titration can be realized.

This application presents the fully automated determination of acidity in jet fuel as per ASTM D3242 via photometric titration with an automatic titrator and the Optrode.

The acid value of fatty acid methyl esters (FAME) like biodiesel can be determined according to EN 14104 using photometric titration with OMNIS and the Optrode.

The concentration of elemental sulfur in gasoline is determined by polarography in acetate containing toluene/methanol electrolyte. The determination is linear up to 2 mg/L with respect to the concentration of elemental sulfur in the measuring vessel. Organic sulfur compounds are not detected with this method. The method is not suitable for diesel fuel, because diesel is not completely soluble in the electrolyte used. The gas wash bottle (6.2405.030) for inert gas supply has to be filled with supporting electrolyte.

The automated combination of pyrolysis and subsequent ion chromatography (Combustion IC) permits the parallel detection of halogens and sulfur in all flammable solid and liquid matrices. The method is captivating, not only because of its outstanding precision and trueness, but also because of the high sample throughput.

Near-Infrared spectroscopy (NIRS) is a widely used analytical technique for quantitative analysis of various products in research and industrial applications. This white paper summarizes the workflow of the development of quantitative methods according to ASTM E1655.

The acid number (AN) is a measure for the quality of oils and their potential to enhance corrosion. When analyzing fresh, unused oils, the AN is used to ensure the specified quality from the manufacturer, whereas for used oils the AN is determined to observe its increase until a critical level is reached. Although it is generally assumed that the AN correlates to the corrosive potential of the oil, this is not exactly correct, as it is the change of the AN value which indicates this issue. Therefore it is necessary to determine the AN on a regular basis.Several standards already exist to determine AN via titration methods, however it is also possible to measure this parameter via spectroscopic (NIRS) methodology. No matter which technique you choose, Metrohm has you covered with high-performance instruments suitable for these published norms.

Underestimation of quality control (QC) processes is one of the major factors leading to internal and external product failure, which have been reported to cause a loss of turnover between 10–30%. As a result, many different norms are put in place to support manufacturers with their QC process. However, time to result and the associated costs for chemicals can be quite excessive, leading many companies to implement near-infrared spectroscopy (NIRS) in their QC process. This paper illustrates the potential of NIRS and displays cost saving potentials up to 90%.

Knowledge of the water content in lubricating oils, additives, and similar products is important in the manufacturing, purchase, sale, or transfer of petroleum products to help estimate their quality and performance characteristics. Monitoring the water content in such products can prevent damage to infrastructure and ensure safe operation by avoiding corrosion processes and subsequent engine wear. This White Paper explains the easy determination of moisture in petroleum samples by coulometric Karl Fischer titration according to the three procedures outlined in ASTM Method D6304. A comparison is given between the procedures to determine which is most suitable for different sample types.