Applications

It has been known for years that consuming too much nitrates from foodstuffs can result in cyanosis, particularly for small children and susceptible adults. According to the WHO standard, the hazard level lies at a mass concentration c(NO3-) ≥ 50 mg/L. However, more recent studies have shown that when nitrate concentrations in the human body are too high, they can (via nitrite) result in the formation of carcinogenic and even more hazardous nitrosamines.Known photometric methods for the determination of the nitrate anion are time-consuming and prone to a wide range of interferences. With nitrate analysis continually increasing in importance, the demand for a selective, rapid, and relatively accurate method has also increased. Such a method is described in this Application Bulletin. The Appendix contains a cselection of application examples where nitrate concentrations have been determined in water samples, soil extracts, fertilizers, vegetables, and beverages.

Determination of strontium and barium in monoethylene glycol using cation chromatography with direct conductivity detection.

Determination of sodium, potassium, iron(II), magnesium and calcium in antifreeze (monoethylene glycol) using cation chromatography with direct conductivity detection. Ascorbic acid reduces iron(III) to iron(II). In this way total iron is determined as iron(II).

This Application Note describes the determination of N,N-diethylhydroxylamine (DEHA), triisopropanolamine (TIPA) and a cationic color developing component (CDC) in a developer solution. The analysis is performed on a high-capacity column such as Metrosep C - 250/4.0 with subsequent direct conductivity detection. To reduce the residence time of the strongly retained color developer components, the column flow rate is increased after the elution of the amines.

2-amino-N-(2,2,2-trifluoroethyl)-acetamide is a organic building block for synthesis of pharmaceutical products. Its purity is crucial for the success of the respective synthesis step. 2,2,2-trifluoroethylamine, glycine, and inorganic cations are of interest. Their total peak area is required to be < 2 % of the peak area of all peaks above the reporting level. Separation and quantification is achieved on a Metrosep C 4 - 250/4.0 cation column.

Hydrogen peroxide is available in different purity grades depending on its use. High purity H2O2 (electronic grade) requires very low contamination levels, e.g., less than 1 μg/L of trimethylamine (TMA). This application describes the determination of trimethylamine in a high-purity H2O2 solution (30%). Analysis is performed using Inline Preconcentration with Matrix Elimination (MiPCT-ME) applying conductivity detection after sequential cation suppression.

Determination of bromide and chloride in photographic developer solutions.

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.

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.

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

The bromine index indicates the degree of unsaturation and relies on the simple addition of bromine to the double bond of alkenes. One mole of bromine is consumed for each mol of carbon-carbon double bond. The bromine index indicates the olefin content in aromatic hydrocarbons. This Application Note describes the determination by coulometric titration according to ASTM D1492.

Karl Fischer reagents contain buffer substances (usually imidazole) since the reaction constant is dependent on the pH value. A constant pH therefore ensures the most repeatable results. In 2015, imidazole was classified by European Union the as a CMR (carcinogenic, mutagenic or toxic) substance and the statement H360D was added, stating possible harm to fertility or a fetus. Meanwhile, other reagents free of imidazole are available for purchase. This Application Note summarizes test measurements with 34433 HYDRANAL™ NEXTGEN Coulomat AG-FI.

Determination of nitrate, sulfate, and thiocyanate in additives for building materials using anion chromatography with direct conductometric detection.

Specialty chemicals have to fulfill multiple quality requirements. One of these quality parameters, which can be found in almost all certificates of analysis and specifications, is the moisture content. The standard method for the determination of moisture content is Karl Fischer titration.This method requires reproducible sample preparation, chemicals, and waste disposal. Alternatively, near-infrared spectroscopy (NIR) can be used for the determination of moisture content. With this technique, samples can be analyzed without any preparation and without using any chemicals.

Determination of citrate, ascorbate, and acetate in photographic developer solution using ion-exclusion chromatography with suppressed conductivity detection.

This Process Application Note presents a way to closely monitor multiple parameters simultaneously during the dioctyl terephthalate production process with near-infrared spectroscopy.

Determination of fluoride, chloride, nitrate, sulfate, and oxalate in a perfluorocarbon material using anion chromatography with conductivity detection after chemical suppression.

Pyrophosphate is used as a stabilizer in aqueous hydrogen peroxide solution. “Reagent grade” solutions may contain pyrophosphate in the higher mg/L range, while “electronic grade” hydrogen peroxide should be free of this stabilizer. Here the determination of pyrophosphate in a high purity H2O2 solution (30%) is performed applying Inline Preconcentration with Matrix Elimination (MiPCT-ME) and a Dose-in Gradient.

The semiconductor industry requires high-purity or even ultrahigh-purity chemicals for the production of electronic components. The purity of the chemicals is crucial for the quality and efficient production of the parts. Here, hydrogen peroxide and ammonium hydroxide are analyzed applying traditional sample preparation methods like digestion and evaporation with subsequent reconstitution with ultrapure water. The received samples are injected applying intelligent Preconcentration Technique (MiPCT).

Determination of cadmium and lead in herbicide powder containing 37% copper after digestion.

The concentration of Pd in an activator bath is determined by polarography in ammonium chloride electrolyte.

Portable Raman is used to characterize the quality of diamond foils made by CVD processes.

Chlorine and caustic soda are used as feedstock materials in myriad production processes for several markets including pulp and paper, petrochem, and pharma. The chlor-alkali process, accounting for 95% of production, depends on the electrolysis of brine, which first requires several steps of purification. This white paper describes the reasoning and benefits for online and inline process analysis over conventional methods for the production of these basic chemicals.

Propylene oxide (PO) is a major industrial product used in assorted industrial applications, mainly for the production of polyols (the building blocks for polyurethane plastics). Several production methods exist, with and without co-products. This white paper lays out opportunities to optimize PO production for safer and more efficient processes, higher quality products, and substantial time savings by using online process analysis instead of laboratory measurements.

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%.

This white paper summarizes the steps involved in converting an existing manual titration procedure to semi-automated or automated titration procedures. It discusses topics such as selecting the right electrode and titration mode. For a better understanding, the discussion topics are illustrated with three examples.

Ion chromatography mass spectrometry (IC-MS) is a powerful tool that can handle many challenging analytical tasks which cannot be performed adequately by IC alone. IC-MS is a robust, sensitive, and selective technique used for the determination of polar contaminants like inorganic anions, organic acids, haloacetic acids, oxyhalides, or alkali and alkaline earth metals. After separation of the sample components via IC, mass selective detection guarantees peak identity with low detection limits. The inclusion of automated Metrohm Inline Sample Preparation (MISP) allows not only water samples, but also chemicals, organic solvents, or post-explosion residues to be readily analyzed without need for extensive manual laboratory work. This White Paper explains the benefits of IC-MS over IC in certain cases, the hyphenation of IC and different MS systems, as well as related norms and standards.

The objective of validation of an analytical procedure is to demonstrate that it is suitable for its intended purpose. Recommendations for the validation of analytical methods can be found in ICH Guidance Q2(R1) Validation of Analytical Procedures: Text and Methodology and in USP General Chapter <1225> Validation of Compendial Procedures. The goal of this white paper is to provide some recommendations for the validation of titration methods.

In this White Paper, you will learn about MIRA XTR DS – the smallest, smartest, most flexible handheld Raman system with the largest libraries available on the market! MIRA XTR DS has all the benefits of 785 nm Raman interrogation: compact size, low laser power, sample preservation, long battery lifetimes... now with fluorescence rejection. Additionally, there is improved sensitivity and resolution over 1064 nm systems. This opens up new possibilities for 785 nm Raman, including strongly colored materials, common excipients, illicit materials, and more.