Aplikace

Analyzer systems monitoring product quality can offer substantial advantages when organized in a client-server network compared to the more traditional local installation. This white paper presents different client-server setups and their benefits. Security aspects that need to be considered are discussed based on the example of the client-server Vis-NIR (visible near-infrared) spectroscopy software Vision Air, widely used for quality control in the chemical, polymer, pharmaceutical, and petrochemical industry.

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%.

With Hydranal™ NEXTGEN FA reagents, the water content in ketones can be determined quickly and reliably. Compared to other existing KF reagents for ketones on the market, the side reactions are measurably better suppressed.

Raman spectroscopy is an advantageous analytical tool that allows for the measurement of molecular structure and identifying chemical composition of materials based on the rotational and vibrational modes of a molecule. With advanced technology and an optimized optical design, the B&W Tek BAC102 series E-grade probe can access lower frequency modes down to 65 cm-1, providing key information for applications in protein characterization, polymorph detection, and identification, along with material phase and structure determination.

Raman spectroscopy is used for material characterization by analyzing molecular or crystal symmetrical vibrations and rotations that are excited by a laser, and exhibit vibrations specific to the molecular bonds and crystal arrangements in the molecules. Raman technology is a valuable tool in distinguishing different polymorphs. Examples of portable Raman spectroscopy for identification of polymorphs and in monitoring the polymorphic transiton of citric acid and its hydrated form are presented.

This article demonstrates the utility of portable Raman spectroscopy as a versatile tool for process analytical technology (PAT) for raw material identification, in-situ monitoring of reactions in developing active pharmaceutical ingredients (APIs), and for real-time process monitoring. Raw material identification is done for verification of starting materials as required by PIC/S and cGMP, and can be readily done with handheld Raman. Portable Raman systems allow users to make measurements to bring process understanding and also provide proof of concept for the Raman measurements to be implemented in pilot plants or large-scale production sites. For known reactions which are repetitively performed or for continuous online process monitoring of reactions, Raman provides a convenient solution for process understanding and the basis for process control.

The present Application Bulletin contains NIR applications and feasibility studies for NIRSystems devices in the chemical industry. Qualitative and quantitative analyses of a wide variety of samples are part of this bulletin. Each application describes the instrument that was originally used for the analysis, as well as the system recommended for the analysis and the results that were achieved thereby.

4-Carboxybenzaldehyde, in the following referred to as 4-CBA, can be reduced directly at the dropping mercury electrode (DME) in an ammoniacal solution. After a very simple sample preparation it is now possible to determine the concentration of 4-CBA in terephthalic acid quickly and precisely by polarography down to the lower ppm range.

Sulfate can be rapidly and easily titrated thermometrically using a standard solution of Ba2+ as titrant. In industry, the widespread procedure is applied to the determination of sulfate in wet-process phosphoric acid.

If chloride and bromide are present in approximately equal molar concentrations they can be titrated directly with silver nitrate solution after addition of barium acetate. If, however, the molar ratio n(Br-) : n(Cl-) changes from 1 : 1 to 1 : 5, 1 : 10, 5 : 1 or 10 : 1 then greater relative errors must be expected with this method. The Bulletin describes an additional titration method that allows bromide to be determined in the presence of a large excess of chloride. The determination of small chloride concentrations in the presence of a large excess of bromide is not possible by titration.

This method is applicable to all samples containing glycerin in the absence of other triols or other compounds that react with periodate to produce acidic products. Glycerin may be determined in the presence of glycols. A periodate solution reacts slowly with diols and triols in acidic aqueous media at room temperature. A quantitative amount of formic acid is generated from the reaction with glycerin (a triol). The reaction with diols produces neutral aldehydes. The amount of formic acid generated by this reaction is determined by titration against sodium hydroxide.

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

Determination of the sulfate content of wet process phosphoric acid.

Determination of acetic anhydride in the presence of acetic acid in acylation mixtures.

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.

Cyclohexane is an important organic solvent. Recycled cyclohexane must be tested for trace substances, e.g., chloride and sulfate. Metrohm Combustion Ion Chromatography with flame sensor and Inline Matrix Elimination is the method of choice.Keyword: pyrohydrolysis

This Application Note describes a fast, nondestructive, and reliable method for the determination of the chemical composition of alcohol mixtures exemplified by ethanol/isopropanol mixtures. With visible near infrared spectroscopy (VIS-NIRS), results are available in real-time, thus making NIRS highly suited for fast quality control.

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.

Near-infrared spectroscopy (NIRS) can determine water content in PGME (propylene glycol monomethyl ether) within seconds as shown in this Application Note.

This Application Note describes the rapid and non-destructive identification of conventional organic solvents using hand-held Raman spectrometers. Measurements with the handheld Raman spectrometer Mira M-1 require no sample preparation and provide immediate and unambiguous results.

This application note presents the Orbital Raster Scan (ORS) technology from Metrohm Raman to overcome low resolution, poor sensitivity, and sample degradation while still interrogating a large sample area.

Determination of calcium and magnesium in high-purity sodium chloride using cation chromatography with direct conductivity detection.

Determination of sodium, potassium, iron(II), magnesium, and calcium in an extract of monoethylene glycol using cation chromatography with direct conductivity detection.

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

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

Determination of acetate, formate, chloride, bromide, and sulfate in toluene using anion chromatography with direct conductivity detection.

This Application Note describes carbonate determination with ion chromatography in a 50% sodium hydroxide solution. Sodium hydroxide solutions form carbonates through the absorption of carbon dioxide from ambient air. The carbonate content of an NaOH solution is determined using ion-exclusion chromatography with subsequent conductivity detection following inverse suppression. The samples are diluted 1:20 prior to the analysis and – in order to prevent CO2 absorption – stored in closed sample vessels.

Determination of chloride and sulfate in potassium tetraborate (KB4O7 * 4 H2O) using anion chromatography with conductivity detection after chemical suppression.

Determination of Cd, Pb, and Cu in brine and NaOH.

This Process Application Note presents a method to closely monitor low levels of moisture in propylene oxide safely and reliably by using a single explosion-proof inline process analyzer.

In the HPPO – hydrogen peroxide to propylene oxide – process for propylene oxide production, hydrogen peroxide is analyzed using a complexing agent and a colorimetric measurement with dipping probe. Due to the hazardous environment, the online analyzer fulfills EU Directives 94/9/EC (ATEX95) and is certified for zone1 and zone2 areas.

In the Solvay process, ammonium hydrogen carbonate and table salt are converted to sodium hydrogen carbonate and ammonium chloride. Heating the former yields sodium carbonate (soda), an important raw material for the soap and glass industries. Ammonia is an incipient and is regenerated almost completely through conversion of the ammonium chloride with lime milk (Ca(OH)2).A Metrohm process analyzer monitors the ammonia content in the saturated table salt solution after absorption tower, thus guaranteeing a good product yield in the carbonization tower. Additional parameters which can be determined with the analyzer in the Solvay process include: alkalinity, carbonate, chloride, calcium oxide and carbon dioxide.

The basic chemicals industry is responsible for producing thousands of raw materials at very large scales. The industries downstream rely upon a certain level of chemical purity to manufacture their own goods, as certain impurities can cause major issues in various processes. During the production of the basic chemicals NaOH and KOH, electrolysis of saturated brine solutions with membrane-cells yield the product which is further concentrated by evaporation. Impurities from the salts used in the brine will also be concentrated. Typically, this impurity analysis is performed offline with various hazardous chemicals with varying shelf-lives. The Process Ion Chromatograph is able to perform the measurement described in ASTM E1787-16 online, ensuring quality product without the need for time-consuming, hazardous laboratory experiments.

Boric acid is growing in demand for various industrial applications, but requires a more cost-efficient and environmentally friendly production process. This Application Note describes the performance of a Raman process analyzer (PTRam) when measuring low-concentration boric acid and sodium sulfate solutions (<100 mg/L) during boric acid production.

Acrylic acid dimerizes spontaneously. Determining the dimer content is, therefore, a key part of the quality control for acrylic acid. One quality control parameter for the dimerization is the acid number. This Application Note describes its determination by automated, potentiometric titration.

Peroxides are often used for disinfection and water treatment purposes due to their antiseptic properties. Lower concentrations between 0.3–3% are used in households, while higher concentrations can be used for sterilization purposes. Additionally, peroxides are utilized as oxidizing and bleaching agents. Peroxides, perborates, and percarbonates can easily be determined by titration. This application note presents two titration methods for peroxide analysis: ASTM D2180 for concentrated hydrogen peroxide solutions, and a second method for trace determination of hydrogen peroxide, suitable for concentrations as low as 0.4 mg/L.

This Application Note describes the photometric determination of sulfate in aqueous solutions using the Optrode (520 nm). Sulfate is precipitated with an excess of barium chloride solution. Excess barium is subsequently titrated with EDTA.

Compounds with carbonyl groups can be prone to oxidation for which reason their stability often decreases during storage or processing. The method presented here is suitable for the determination of aldehydes and ketones sparingly soluble in water.Samples are dissolved in deionized water. After a reaction with the hydroxylamine hydrochloride at 50 °C, carbonyl groups are quickly and accurately determined by potentiometric titration using the dUnitrode and sodium hydroxide as titrant.

The hydroxyl number is an important sum parameter for quantifying the presence of hydroxyl groups in a chemical substance. As a key quality parameter, it is regularly determined in various polymers like resins, paints, polyesterols, fats and solvents. Unlinke other standards, ASTM E1899 works pyridine-free and without refluxing at elevated temperatures for a longer time. It is performed at room temperature, requires only a small sample size, is applicable to extremely low hydroxyl numbers (<1 mg KOH/g sample) and can be performed fully automatically. This Application Note describes the potentiometric determination of the hydroxyl number in 1-octanol and polyethylene glycol according to ASTM E1899, EN 15168 and DIN 53240-3. Using the OMNIS DIS-Cover technique all sample preparation steps can be fully automated. Moreover, the use of an OMNIS Sample Robot allows parallel analysis of multiple samples. The average time per analysis for one sample is thus reduced from approximately 24 min to 12 min., increasing productivity in the laboratory considerably.

The iodine adsorption number (IAN) of carbon black is related to the surface area and can therefore be used for the characterization of carbon black. The presence of volatiles, surface porosity, or extractables will influence the iodine adsorption number. In this Application Note, the fully automated determination of the iodine adsorption number including sample preparation is described.

Hydrochloric acid is a strong, inorganic mineral acid with great significance in the chemical industry. The potentiometric titration of hydrochloric acid with sodium hydroxide is one of the most important and also most frequent analyses performed in the laboratory. In this Application Note, an acid-base titration is presented where the concentration of HCl is determined with NaOH using a pH electrode with an integrated Pt1000 temperature senor for the most accurate results

Phosphoric acid is a triprotic inorganic acid used for many purposes: as a raw material for the production of phosphate fertilizers, detergents, as an electrolyte in phosphoric acid fuel cells, rust removers, and for the passivation of iron and zinc to protect against corrosion. This Application Note presents an acid-base titration where the concentration of phosphoric acid is determined over all three of its dissociable protons by titrating it with sodium hydroxide.

Determination of hypophosphite, formate, phosphate, adipate, p-nitrobenzoate, and sebacate in ethylene glycol using anion chromatography with conductivity detection after chemical suppression.

Determination of phosphate and tetrafluoroborate in 2% HF using anion chromatography with conductivity detection after chemical suppression.

Determination of chloride, nitrate, and sulfate in methanol using anion chromatography with conductivity detection after chemical suppression.

Determination of acetate, chloride, nitrate, and sulfate in aluminum oxide using anion chromatography with conductivity detection after chemical suppression.

Determination of traces of fluoride and sulfate in 35% hydrochloric acid (HCl) using anion chromatography with conductivity detection after chemical suppression and sample preparation by inline neutralization.

Determination of chlorate and sulfate in a brine solution (1.5% NaCl) using anion chromatography with conductivity detection after chemical suppression.

Determination of oxalate, thiosulfate, and thiocyanate in an amine solution using anion chromatography with conductivity detection after chemical suppression.

Determination of chloride, chlorate, and sulfate in soda lye (50% sodium hydroxide) using anion chromatography with conductivity detection after sequential suppression and Metrohm Inline Neutralization.