Applications

Botanicals are derived from plant materials and used for their medicinal and therapeutic properties in the nutraceuticals market. They are not as heavily regulated by the U.S. Food and Drug Administration (FDA) like the pharmaceuticals drug market, but they are required to follow Good Manufacturing Practice (GMP Requirements).The NanoRam®-1064 is an asset for pharmaceutical identity testing, minimizing fluorescence generated by typical handheld Raman systems with 785 nm lasers. As such, the NanoRam®-1064 is used here to identify botanicals that would normally fluoresce with a 785 nm laser.

Although the process of building, validating and using a method is well-defined through software, the robustness of the method is dependent on proper practice of sampling, validation, and method maintenance. In this document, we will detail the recommended practices for using the multivariate method with NanoRam-1064. These practices are recommended for end users who are in the pharmaceutical environment, and can expand to other industries as well. This document aims to serve as a general reference for NanoRam-1064 users who would like to build an SOP for method development, validation and implementation.

Compared to the classical Epton titration, potentiometrically indicated two-phase titrations using organic-solvent-resistant Surfactrodes can be easily automated and require no toxic and environmentally hazardous chloroform. Even challenging matrices such as fats and oils in bath oils and hair conditioners or strong oxidizing agents in washing powder and industrial cleaners do not interfere with the titration of the ionic surfactants. Results obtained show excellent agreement to those of the Epton titration. Irrespective of the matrix, relative standard deviations of threefold determinations are all below 2.1%. While the Surfactrode Resistant is mainly used for oil-containing formulations, the Surfactrode Refill is ideal for washing powders and soaps. Both electrodes excel by their ruggedness and allow the rapid and precise determination of anionic and cationic surfactants.

This Application Bulletin gives an overview of the volumetric water content determination according to Karl Fischer. Amongst others, it describes the handling of electrodes, samples, and water standards. The described procedures and parameters comply with the ASTM E203.

This Bulletin describes fluoride determination in various matrices with the help of the ion-selective fluoride electrode (F-ISE). The F-ISE is comprised of a lanthanum fluoride crystal and exhibits a response in accordance with the Nernst equation across a wide range of fluoride concentrations.The first part of this Bulletin contains notes regarding the handling and care of the electrode and the actual fluoride determination itself. The second part demonstrates the direct determination of fluoride with the standard addition technique in table salt, toothpaste and mouthwash.

This Application Bulletin gives an overview of the coulometric water content determination according to Karl Fischer.Amongst others, it describes the handling of electrodes, samples, and water standards. The described procedures and parameters comply with the ASTM E1064.

Application Bulletin AB-076 contains a description of the polarographic determination of low concentrations (1–100 mg/L) of NTA and EDTA in bodies of water. NTA, EDTA and citrate have gained in importance as complexing agents and builders due to the fact that the laws of some countries have made it necessary to find a substitute for phosphates in detergents.This Bulletin describes the determination of larger quantities of complexing agents in detergents using potentiometric titration. The ion-selective copper electrode (Cu-ISE) is used here as the indicator electrode. The determination of complexing agents is not disturbed by the other constituents often present in detergents.

The titrimetric determination of nonionic surfactants on the basis of polyoxyethylene adducts (POE adducts) is described in the Bulletin. The basis for the determination is the transfer of the nonionic surfactant into a pseudo-cation compound and its precipitation titration with sodium tetraphenylborate (Na-TPB). The NIO electrode is used for the indication of the potentiometric titration. This Bulletin describes determinations in raw products, formulations and wastewater and draws attention to special features, possibilities, limits and disruptions.

Anionic surfactants can be titrated with cationic surfactants and vice-versa. The Bulletin describes a multitude of substances that can be determined in this fashion and specifies the respective working conditions and parameters. In contrast to the classic two-phase titration in accordance with Epton, the titration with the anionic and cationic surfactants electrodes can be performed without chloroform. Furthermore, the equivalence point of the titration is difficult to determine in some cases with the Epton method and the titration cannot be automated.In many cases, a surfactant ISE is a remedy that is both environmentally friendly and suitable here. It was developed specially for application with potentiometrically indicated surfactant determinations.

The two potentiometric titration methods described here allow the determination of the content of commercial betaine solutions. Neither method is suitable for determining the betaine content of formulations. The possibilities and limits of both methods are described and distinctive features and possible sources of interference are mentioned. The Bulletin explains the most important theoretical principles and is intended to help users to develop their own product-specific titration methods.

The present Bulletin offers an overview of the multitude of surfactants and pharmaceuticals that can be determined with potentiometric titration. Metrohm provides five different surfactant electrodes for indicating the titration endpoint: the Ionic Surfactant, the High Sense, the Surfactrode Resistant, the Surfactrode Refill and the NIO Surfactant electrode. The manufacture of the respective titrants and their titer determination are described in detail. In addition to this, the Bulletin contains a tabular overview of more than 170 proven applications from the area of surfactant and pharmaceutical analysis. This guideline leads you reliably to your destination: At a glance you can see from the table which surfactant electrode and which titrant are optimally suitable for your product.

On the basis of a multitude of practical examples, this Bulletin describes the potentiometric two-phase titration of ionic surfactants in raw materials and many other formulations.Two surfactant electrodes – the Surfactrode Resistant and the Surfactrode Refill – make it possible to perform this type of surfactant titration, analogous to the classic "Epton titration", with a high degree of automation. The achieved results correlate very well with those of Epton titration. The toxic, carcinogenic and environmentally hazardous chloroform can be replaced by other solvents such as methyl iosbutyl ketone or n-hexane.

This Application Bulletin describes the determination of Sn(II) in presence of Sn(IV) by anodic stripping voltammetry (ASV). Using an electrolyte containing fluoride, Sn(IV) gives no signal, so that a speciation is possible. The limit of detection is 2.5 µg/L.

Pyrithione complexes, such as zinc pyrithione (ZnPT), copper pyrithione (CuPT), and sodium pyrithione (NaPT), are used as fungicides and bactericides. ZnPT is used in the treatment of skin conditions such as seborrheic dermatitis or dandruff. Furthermore, ZnPT is sometimes used as an antibacterial agent in paints to prevent algae and mildew growth. CuPT is primarily in use as a biocide to prevent biofouling of surfaces submerged in water. Meanwhile, NaPT is used as antifungal agent for treatment of mycosis, such as athlete’s foot. The different pyrithione complexes are determined by iodometric titration using a maintenance-free Pt Titrode for the indication.

Determination of 3-dimethylamino-1-propylamine in cocoamidopropyl betaine using cation chromatography with direct conductometric detection.

Determination of sodium and potassium in toothpaste using cation chromatography with direct conductivity detection.

Palm oil is a vegetable oil that is used not only in the food industry but also for the manufacture of soaps and body care products. It is furthermore an important raw material for the generation of biodiesel. Depending on the degree of refinement, palm oil can be red, reddish or even colorless in appearance. The carotenes responsible for the color are removed during refinement and the oil becomes increasingly clear. In this Note, the chlorine and sulfur content of various palm oils are determined using Combustion IC.Keyword: pyrohydrolysis

Determination of a nonionic surfactant of the alkyl propylene oxide derivative type in commercial mixtures containing anionic surfactants.

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).

This Application Note describes the automated determination of the water content in toothpaste using volumetric Karl Fischer titration (MATi 10).

Determination of key quality parameters of palm oil, namely free fatty acids (FFA), iodine value (IV), moisture content, deterioration of bleachability index (DOBI), and carotene require the use of several different analytical methods, which are laborious and can lack in accuracy. 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 determination of these quality control parameters in palm oil. With no sample preparation or chemicals needed, Vis-NIR spectroscopy allows for the analysis of palm oil in less than a minute and can be used by anyone.

Vis-NIR spectroscopy is used to determine the droplet morphology in hair conditioner. This Application Note shows that near-infrared (NIR) spectroscopy can be used to distinguish between unprocessed and processed hair conditioner and to qualify quality parameters such as the droplet size.

Near-infrared spectroscopy (NIRS) was used in a preliminary study as a fast and accurate method for the quantification of different preservatives and active ingredients in liquid shampoo. This Application Note shows how this analytical method allows the simultaneous determination of several constituents in shampoo in a single measurement.

Near-infrared spectroscopy (NIRS) was used as an analysis method for quality control of soap noodles. Quantitative models for the determination of Total Fatty Matter, Iodine Number, and C8–C14 were developed, enabling fast and reliable quality control.

Near-infrared spectroscopy (NIRS) was used as an analysis method for quality control of aqueous xanthan gum solutions. Quantitative models for the determination of optical density, glucose, and xanthan gum were developed, enabling fast and reliable quality control.

Near-infrared spectroscopy (NIRS) was used for quality control of skin creams. A model for the quantification of the water content was developed based on Karl Fischer titration (KF), enabling fast and reliable atline analysis and final product quality control.

This Application Note shows that visible near-infrared spectroscopy (Vis-NIRS) can determine the sun protection factor (SPF) of sunscreen products. Thanks to measurement durations of less than 30 seconds, NIR spectroscopy is ideally suited for rapid and reliable quality control.

Rapid quality control for toothpaste is achieved by Metrohm`s Vis-NIR analyzers. Vis-NIR technology offers significant advantages compared to standard reference analysis. It is a cost effective and safe method because no hazardous chemicals are used.

This Application Note shows how NIRS is used for the multiparameter analysis of dry matter, pH value, viscosity, and surfactant content in liquid laundry detergent.

Safe and fast ethanol determination in hand sanitizers is possible with reagent-free near-infrared spectroscopy (NIRS). NIRS provides reliable results in a few seconds, quickly indicating when adjustments in formulation are necessary.

This application note presents near-infrared spectroscopy (NIRS) for the rapid and reliable simultaneous quantification of ethanol, glycerol, hydrogen peroxide, and water content in hand sanitizer formulations.

Near-infrared spectroscopy (NIRS) quickly assesses key quality parameters in palm oil such as iodine value and fatty acid profile without sample preparation.

This Application Note shows how near-infrared spectroscopy is used for fast, chemical-free multiparameter quality control of fabric softeners and laundry perfumes.

Near-infrared spectroscopy (NIRS) can simultaneously determine different quality parameters in deodorants like viscosity, pH, density, and aluminum content.

Determination of glycolic acid and monochloroacetic acid in cocoamidopropyl betaine using ion-exclusion chromatography with direct conductometric detection.

Polyols and sugars in soaps enhance the stability and the size of air bubbles and foam. In addition to the polyol glycerin, sugar alcohols and sugars are often added to soaps. The determination of sorbitol and saccharose in a transparent soap takes place on a column of the Metrosep Carb 2 - 150/4.0 type with subsequent pulsed amperometric detection (PAD).

Using the Rancimat method, the oxidation stability of suntan oil can be determined reproducibly and reliably.

Lipsticks and lip balms consist mainly of natural oils such as seed oils, palm oils or coconut oils. Many manufacturers additionally enhance their product with various vegetable fats, oils and wax. The purpose of these additives is to increase the perceived quality of the products. However, some of these oils and fats are capable to oxidize by autoxidation over time which affects the shelf life and therefore the quality of the products negatively. A reproducible and accurate determination of the oxidation stability using the 892 Professional Rancimat can be realized.Find the method explained in the Metrohm LabCast video at https://youtu.be/xdOmyeyc7Cs

Some samples, such as cosmetics and food, cannot be measured directly with the Rancimat as no evaluable induction time is obtained. There are many reasons for this, for example a high water content, a too low fat content or various matrix effects. However, using polyethylene glycol (PEG) as carrier material, many of these samples can be directly and reproducibly measured without sample preparation. This is due to the antioxidants that are naturally present in the sample matrix, and which stabilize the induction time of the PEG. The induction time can therefore be directly related to the oxidation stability of the sample.Furthermore, with a standard addition it is possible to measure the content of antioxidants (AOC) such as vitamin E, vitamin C or an equivalent of it. The decrease of the antioxidants over time (for example, during storage of the sample) can thus be measured and evaluated. In addition, this method eliminates a costly sample preparation. A reproducible and accurate determination of the oxidation stability using the 892 Professional Rancimat can be realized.

The oxidation stability is an important factor for the quality of cosmetics. It also provides information about the long-term and storage stability of the product. Most cosmetic formulations cannot be measured directly with the Rancimat as no evaluable induction time is obtained. There are many reasons for this, for example a high water content, a too low fat content or various matrix effects. However, using polyethylene glycol (PEG) as carrier material, many of these samples can be directly and reproducibly measured without sample preparation. This is due to the antioxidants that are naturally present in the sample matrix, and which stabilize the induction time of the PEG. The induction time can therefore be directly related to the oxidation stability of the sample.In addition, this method eliminates a costly sample preparation. A reproducible and accurate determination of the oxidation stability using the 892 Professional Rancimat can be realized. In this Application Notes the oxidation stability of body care cream, moisturizer, body milk, body lotion, and toothpaste is determined in this way. More information on the Rancimat method can be found on the Metrohm website.

Determination of the identity and purity of ingredients is essential for the product quality of functional foods (neutraceuticals) and cosmetics. It prevents the utilization of inferior substances in the production process and thus avoids expensive delays and out-of-spec products. This Application Note describes the identification and checking of fatty acids in functional foods and cosmetics using the Metrohm Instant Raman Analyzer MIRA P.

This Application Note explains how to scale MIRA P usage across an entire manufacturing operation by transferring models between different MIRA P instruments.

This application shows how to seamlessly transition from Metrohm’s NanoRam 785 to the newer MIRA P system, ensuring continuity in raw material identification (RMID).

Determination of chloride, sulfite, and sulfate in a surfactant solution using anion chromatography with conductivity detection after chemical suppression.

Determination of fluoride, chloride, bromide, and sulfate in bath salts (sea salt) using anion chromatography with conductivity detection after chemical suppression.

Determination of fluoride, chloride, phosphate, monofluorophosphate, and sulfate in toothpaste using anion chromatography with conductivity detection after chemical suppression.

Determination of fluoride, glycolate, monochloroacetate, and chloride in a surfactant solution using anion chromatography with conductivity detection after chemical suppression and dialysis for sample preparation.

Determination of octylsulfonate, octylsulfate, dodecylsulfate, and oleate in a shower cream using reversed phase chromatography with conductivity detection after chemical suppression applying gradient elution.

Whitening toothpaste often contains polyphosphates to remove stains. The analysis of these polyphosphates requires a high-pH hydroxide eluent. The high eluent concentration is suppressed by the high-capacity suppressor MSM-HC.

Monofluorophosphate is used in toothpaste to prevent dental caries. USFDA allows up to 1.5 g/kg fluoride corresponding to 11.5 g/kg sodium monofluorophosphate on over the counter (OTC) dentifices for adults and children above 6 years. Here, a toothpaste is analyzed for monofluorophosphate by ion chromatography applying conductivity detection after chemical suppression.

Dental care products often contain sodium fluoride as an active ingredient. Manufacturers use the United States Pharmacopeia and National Formulary (USP-NF) Monograph «Sodium Fluoride» to quantify sodium fluoride and its anionic contaminants chloride and acetate in these products. The validated USP method proposes ion chromatography (IC) with suppressed conductivity detection to carry out the fluoride assay as well as the impurity determination in a single chromatogram.

Sodium fluoride gel for pharmaceutical use needs to comply with USP requirements. The actual monograph (USP 42) uses two different methods for the identification and the assay. Ion chromatography allows the analysis of these two parameters in one single determination. In the course of the USP monograph modernization, this ion chromatographic approach makes this type of analysis even easier.

Anticavity pharmaceuticals like sodium fluoride and acidulated phosphate topical solution products require strict quality control. This Application Note outlines the fluoride IC assay as described in the USP Monograph Sodium Fluoride and Acidulated Phosphate Topical Solution.

Determination of anionic surfactants in shower lotions and shampoos by potentiometric titration with TEGO®trant A100 using the «Ionic Surfactant» electrode.

Determination of cationic surfactants in hair conditioner by potentiometric titration with dioctyl sodium sulfosuccinate using the «Ionic Surfactant electrode.

Determination of the cationic surfactant «cetrimide» in an antiseptic disinfectant by potentiometric titration with sodium dodecyl sulfate using the «Ionic Surfactant» electrode.

Determination of chlorhexidine in wash lotion by potentiometric titration with sodium tetraphenylborate using the NIO surfactant electrode.

Determination of anionic surfactants in shower oil by potentiometric two-phase titration with TEGO®trant A100 using the «Surfactrode Resistant» electrode.

Determination of cationic surfactants in a household cleaner by potentiometric two-phase titration with sodium dodecylsulfate using the «Surfactrode Resistant» electrode.

Due to its price and wide availability, the anionic surfactant sodium lauryl sulfate (SLS; SDS) can be found in many detergents as an emulsifier or as a fat solvent e.g., in cleaning or cosmetic products. To avoid causing severe dry skin and hair, and thus skin irritation, regulations in many countries have restricted the sodium lauryl sulfate concentration in ready-to-use products to a range between 0.05–2.5% SLS. To control the concentration of SLS in different products, a titration is carried out with TEGO® trant A100 and the Optrode. The evaluation is done automatically by means of a software, leading to reliable and reproducible results.

In many countries, the aluminum concentration in water is limited to 0.2 mg/L. This application note shows how the analysis of aluminum in water can be done fully automatically by complexometric titration with EDTA.

The hydroxyl number (HN) is an important sum parameter for quantifying the presence of hydroxyl groups in chemicals. As a key quality parameter, it is determined in various substances. For pharmaceutical samples, USP chapter <401> and Ph. Eur. Chapter 2.5.3 describe the determination. However these methods either use toxic pyridine and require refluxing or have long reaction times.In this Application Note, an alternative method according to ASTM E1899 is presented. This method is pyridine-free and does not require refluxing or long reaction times. The determination is performed at room temperature with only a small sample size. The analysis including all preparation steps is performed with a fully automatic OMNIS system. This allows parallel analysis of multiple samples, increasing productivity in the laboratory by 50%.

Aluminum and magnesium ion mixtures are analyzed using back-titration at different pH values. The ion-selective copper electrode is used here as the indicator electrode. First, the aluminum is determined in acidic solution and then the magnesium in alkali solution.

Inorganic sulfate is determined in secondary alklysulfonate (raw material) in accordance with DIN EN 14880 with the use of the Pb ISE.

Alkyl glycosides, alkyl maltosides and compounds with polyoxyethylene groups (POE) are numbered among the nonionic surfactants. These surfactants can be analyzed by standard titration with TEGO®trant following derivatization – in this case following sulfonation.

OMNIS is the ideal system for quick and accurate determination of aluminum in aluminum chloride using complexometric back titration with an ion-selective copper electrode (Cu-ISE). Copper sulfate is used as the titrant.

Complexing agents such as EDTA are used in soaps and other detergents in order to remove unwanted metal ions and to lower water hardness. The EDTA content in soaps and detergents can be determined using potentiometric titration with copper sulfate as titrant and the Cu-ISE as electrode.

Anionic surfactants represent, by volume, the most important group of surfactants used in cleaning products. The potentiometric two-phase titration is a universal method for the accurate and fast determination of them. Using the Surfactrode Refill, the anionic surfactants are determined by potentiometric titration with hyamine as titrant.

Sodium hypochlorite and sodium chloride can be effectively use as disinfectant for water and surfaces. The World Health Organization (WHO) recommends, depending on the application, concentrations in disinfectants of 1000 mg/L to 5000 mg/L NaOCl and up to 200 g/L NaCl.This Application Note demonstrates a reliable method to determine the hypochlorite and sodium chloride content in disinfectants by two subsequent argentometric titrations in the range recommended by the WHO.

This Application Note shows the automatic pH adjustment of a mixture of acetonitrile, water and amine using a Metrohm titrator.

This Application Note presents a complementary method that allows a consecutive determination after the sample preparation (digestion) of both metal ions in one beaker with an optical sensor and xylenol orange as an indicator.

Mannitol content determination is an important aspect of quality control in the pharmaceutical and food industries. Selective oxidative cleavage can be used to quantify the amount of 1,2-diol groups in the analyte. Determining the 1,2-diol content by iodometric titration can be fully automated for the most accurate results using an automated titrator and the dPt Titrode from Metrohm.

Direct titration is a simple and precise way to accurately measure the caffeine content in different nonaqueous products. The OMNIS Titrator equipped with a dSolvotrode reliably determines caffeine through flexible analyses combined with high-end software.

The iodometric back titration is a precise method used to accurately measure the caffeine content in various aqueous samples. Reliable determinations are made easy using the OMNIS Titrator equipped with a dPt Titrode.

Accurate, reliable determination of ionic surfactants with the Epton two-phase titration method can be achieved using an OMNIS system as shown in this study.

Manufacturers and laboratories must use validated methods to determine the zinc content in skin care products and pharmaceutical supplements to meet strict quality standards set by the United States Pharmacopeia and National Formulary (USP-NF). USP-NF has updated the zinc monograph (General Chapter <591>, Zinc Determination) and replaced the existing identification procedure of titration with ion chromatography (IC). The analysis involves separating Zn using a Metrosep A Supp 10 column followed by post-column reaction using 4-(2-pyridylazo)resorcinol and detection at 530 nm.

Thiomersal (also called thimerosal) is a mercury containing organic molecule that has been widely used as preservative for vaccines and eye drops. It is very effective, even in very low concentrations, against a wide range of microorganisms and viruses. To reduce the risk for consumers the maximum concentration of mercury in the products is limited by the authorities. Polarography or voltammetry can be used to accurately determine the concentration of thiomersal in vaccines or other cosmetic and pharmaceutical solutions (such as eye drops). The method is simple to perform, specific, and free of interferences.

The raw materials whey, sorbitol, stearic acid, and calcium phosphate dihydrate dibasic all show very distinctive, unique Raman signatures, which indicates that Raman spectroscopy is the ideal technology for identification of these materials. The PCA model-based method provides reliable specificity to successfully identify these nondestructively in plastc samples bags using the NanoRam.

Rancidity of oils and fats is a factor which can immediately reduce the sale price of these products to customers in the food and cosmetics industries. Oils which remain stable over longer periods of time are more highly valued as they lead to a higher quality end product. Rancidity is a natural process which occurs as fats and oils age and oxidize, and can be delayed or even stopped by addition of antioxidants at the right time.Determination of rancidity is possible in several ways (e.g., measuring the acid number or peroxide value), though these tests only give information about the current state of the product, with no indication about the remaining shelf life. One analytical method that can measure this time span until spoilage is the Rancimat method, which artificially ages the samples to determine whether antioxidants may be needed to help manufacturers get the full value from their oils.

This White Paper discusses the concept and benefits of NIR spectroscopy and outlines several real-life laboratory application examples with the use of OMNIS NIRS, the cutting-edge NIR spectrometer from Metrohm.

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