Aplikácie

This Process Application Note is dedicated to the online analysis of zinc, iron and sulfuric acid in several stages of the zinc production process. Additionally, traces of germanium, antimony, as well as several transition metals (e.g., Ni, Co, Cu, Cd) can be precisely determined (<50 µg/L) in the purification filtrates and reactor trains.

Excessive silica concentrations in the boiler feed water can lead to deposits on turbine blades and must therefore be avoided. Silica analysis is carried out via differential photometry using a leading-edge technology thermostatic cuvette module for non-sample contact at the detector. Typical concentration ranges for silica are 0–50 ppb and 0–1 ppm or higher.

This Process Application Note details the simultaneous online analysis of H2S and NH3 in sour water which was previously treated in the sour water stripper (SWS). The method includes automatic cleaning and calibration. Fast and accurate results are continuously supplied for process control.

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).

Lithium salts (e.g., lithium carbonate and lithium hydroxide) are used in myriad applications. Lithium hydroxide is used for the production of lithium stearate, an important engine lubricant. In addition, it is utilized as an air purifier due to its ability to bind carbon dioxide. While the majority of lithium carbonate is used for aluminum production, it is also used for the glass and ceramic industry. It lowers the melting point of these materials, lowering the associated electricity costs and making it cheaper to produce them.For all of these applications, it is important to know the quality of the pure lithium salts used in the various production processes. This Application Note presents an easy method for the assay of lithium hydroxide and lithium carbonate on an automated OMNIS system.

In order to maintain product quality, the sodium chloride content in meat products must be monitored, as the limit values defined by the respective public health authorities must not be exceeded. The chloride content in food correlates with the salt content, its determination is therefore described in various norms and standards. However, preparation of meat samples is time consuming, as it requires homogenization with a mixer and a chloride extraction with water.In order to reduce workload and working hours, this Application Note describes a fully automatic potentiometric titration of chloride with silver nitrate in meat products based on ISO 1841-2, including fully automated sample preparation using a Polytron homogenizer.

In this application note, a fully automated system is presented which allows the determination of several parameters according to various standards within one analysis. These include conductivity (ISO 7888, EN 27888, ASTM D1125, EPA 120.1), the pH value (EN ISO 10523, ASTM D1293, EPA 150.1), alkalinity (EN ISO 9963, ASTM D1067, EPA 310.1), and Ca/Mg content (ISO 6059, ASTM D1126, EPA 130.2). Additionally, the system transfers the required sample volume into an external titration vessel for the analysis, reducing manual sample preparation. Furthermore, all sensors can be automatically calibrated and the titer of each titrant can also be determined.

In this application note, a fully automated system is presented which allows the determination of several parameters according to various standards within one analysis. These include conductivity (ISO 7888, EN 27888, ASTM D1125, EPA 120.1), pH value (EN ISO 10523, ASTM D1293, EPA 150.1), alkalinity (EN ISO 9963, ASTM D1067, EPA 310.1), Ca/Mg (ISO 6059, ASTM D1126, EPA 130.2), and chloride (ISO 9297, ASTM D512, EPA 325.3). Additionally the system transfers the required volume of sample into external titration vessels for the different analyses, reducing manual sample preparation. Furthermore, all sensors can be automatically calibrated and the titer of each titrant can also be determined.

The permanganate index (PMI) is a sum parameter that indicates the total load of oxidizable organic and inorganic matter in water. The substances concerned are mainly humic materials/acids that are primarily formed when dead organic material present in soil is further broken down and released into water sources. As it is an indicator of the water quality, testing of the PMI for drinking water is obligatory in many countries.For the determination, it is necessary to heat the stabilized water sample to 95 °C and higher for a stipulated time. Afterwards, the amount of permanganate that has remained after the reaction with the sample is determined titrimetrically. This sample preparation step requires considerable manual effort.In this Application Note, a fully automated procedure for the determination of the PMI according to GB/T 11892 is described, including all sample preparation steps. The gains in productivity because of a reduced manual workload are considerable.

Boehm titration is a quantitative analysis of functional groups on the surface of carbon materials based on their reactions with basic solutions of NaHCO3 (pKa = 6.4), Na2CO3 (pKa = 10.3), and NaOH (pKa = 15.7). This is a cost-efficient method that gives absolute values with high precision of the accessible, mainly oxygen-containing functional groups on the surface. Originally, Boehm titration was developed for carbon materials like conductive carbon black (CCB), activated carbon, porous carbon, and graphite. Modern carbon-based materials like graphene, graphene oxide (GO), or carbon nanotubes can also be analyzed this way.

Boric acid requires precise monitoring in the primary circuit to control nuclear reactor reactivity. The 2060 TI Process Analyzer monitors boric acid online in near-real time.

Raw oil contains several percent by weight of sulfur compounds. They not only have an unpleasant smell, they are also environmentally harmful and corrosive which is why they must be largely removed during refining. The 2045TI Ex proof Analyzer with a flexible sample pretreatment system is to be found in a very wide variety of refinery applications. On the one hand, it monitors mercaptan and H2S content in accordance with ASTM D3227 and UOP163; on the other hand it can be used for the determination of ammonia, halogen and phenol content as well as for the bromide index, saponification and acid number. The analyzer fulfills EU Directive 94/9/EC (ATEX95) and is certified for Zones 1 and 2.

The Kraft process is the dominant pulping process in the pulp and paper industry with the highest chemical recovery efficiency. In order to run each part of the papermaking process optimally, constant quality checks and analyses should be performed. This Process Application Note illustrates the straightforward online analysis of alkali (active, effective, total titratable alkali (TTA)), carbonate, hydroxide, sulfide and the causticizing degree (CE%) in pulping liquors using a 2060 Process Analyzer from Metrohm Process Analytics.

In this application note, a fully automated system is presented which allows the determination of several parameters according to various standards within one analysis. These include conductivity (ISO 7888, EN 27888, ASTM D1125, EPA 120.1), pH value (EN ISO 10523, ASTM D1293, EPA 150.1), alkalinity (EN ISO 9963, ASTM D1067, EPA 310.1), and chloride content (ISO 9297, ASTM D512, EPA 325.3). Additionally the system transfers the required volume of sample into an external titration vessel, further reducing manual sample preparation. Furthermore, all sensors can be calibrated automatically and the titer of each titrant can also be determined.

The saponification value evaluates edible oil quality by indicating the average molecular weight of fatty acids. Its titrimetric determination in canola and olive oil is described here.

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. Unlike other standards, EN 4629-2 works pyridine-free and without refluxing at elevated temperatures for a longer time. The determination is based on the catalytic acetylation of the hydroxyl group. It is performed at room temperature, requires only a small sample volumen, and can be fully automated.This Application Note describes the potentiometric determination of the hydroxyl number in 1-octanol and polyethylene glycol according to EN 4629-2. Using the OMNIS DIS-Cover technique, all sample preparation steps can be fully automated. Furthermore, 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 49 min to 25 min., considerably increasing productivity in the laboratory.

Lithium is a soft metal which is used for many applications, such as production of high-temperature lubricants or heat-resistant glass. Furthermore, lithium is used in large quantities in for battery production. It is obtained from brines and high-grade lithium ores. Depending on the lithium concentration, extraction may or may not be economically viable.This Application Note demonstrates a method to determine the lithium concentration in brines by potentiometric titration. Lithium and fluoride precipitate in ethanol as insoluble lithium fluoride. Using ammonium fluoride as the titrant and a fluoride ion-selective electrode (ISE), determination via potentiometric titration is possible. This method is more reliable, faster, and less expensive than the determination of lithium in brine by other more sophisticated techniques such as atomic absorption spectroscopy (AAS).

Vitamin C, also known as ascorbic acid or L-ascorbic acid, is an essential nutrient involved in the repair of tissues and the enzymatic production of certain neurotransmitters. It is required for the functioning of several enzymes and immune performance, and is also an important antioxidant. This nutrient is found in many foods and is often used as a dietary supplement.This Application Note describes the photometric determination of ascorbic acid according to the standard ISO 6557-2. To increase the objectivity on the determined equivalence point and the reproducibility of the results, an autotitrator equipped with a photometric sensor, the Optrode, is used. The titrant 2,6-Dichlorophenol-indophenol (DCIP or DPIP) simultaneously serves as titrant and indicator.

Coagulation and flocculation are an essential part of treating both drinking water and wastewater. Aluminum salts such as aluminum sulfate and polyaluminum chloride (PAC) are often used for this purpose. For the precise application and exact dosage of the flocculant, it is important to accurately determine its aluminum content. In this Application Note, the aluminum content is accurately and reliably analyzed based on ABNT NBR 11176 using the 859 Titrotherm equipped with a Thermoprobe HF and sodium fluoride as titrant.

Sodium lactate is a salt form of lactic acid used in many regulated industries—therefore an accurate determination of the lactate content is required and is already covered in several norms. One such monograph by the US Pharmacopoeia (USP) results in high accuracies and well-defined titration curves but uses titrants and solvents that are more costly than necessary. In comparison, the presented modified method from Metrohm requires a 1:1 mixture of water and acetone and uses aqueous hydrochloric acid as titrant, resulting in an estimated cost reduction of 40% per titration compared to the USP method (USP–NF 2021, Issue 2). Furthermore, the time needed for each analysis is reduced to just 12% of the USP method (excluding blank determination). This Application Note presents both methods to determine lactate content and shows the results obtained on an OMNIS system.

ASTM D8192 describes the photometric titration of the total hardness, calcium hardness, and magnesium hardness in water with an optical sensor for objective endpoint indication, increasing precision and reliability. The method is suitable for both colored and colorless samples such as groundwater, surface water, wastewater, and drinking water. Using a fully automated OMNIS system equipped with an Optrode ensures that the sample preparation and analysis are repeatable.

This Application Note compares the OMNIS Titrator and 888 Titrando for determinations of nitric acid, phosphoric acid, and acetic acid in an aluminum etching bath, as well as the determination of tetramethylammonium hydroxide (TMAH). Identical analysis parameters were used, showing that OMNIS delivers results on par or even better than with other established titration systems.

Metrohm has partnered with industry leaders to develop an alternative standard for the measurement of acid number (AN) in crude oil and petroleum products to overcome shortcomings in the current method (ASTM D664). This new standard method (ASTM D8045) describes the use of thermometric catalytic titration for this analysis. Results agree closely with those from ASTM D664, but the thermometric catalytic titration method is far superior in terms of reproducibility and speed of analysis, with determinations being complete in one minute.Solvent usage is much less compared to older methods, saving on waste disposal cost. Comparison studies show very close data correlation between ASTM D8045 and traditional potentiometric AN titration methods making implementation into a refinery with historic data practical.

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.

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.

Corrosion of metallic components is an inherent problem for engines, because metals naturally tend to oxidize in the presence of water and/or low pH value. The reserve alkalinity of engine coolants and antirusts is a measure of the buffering ability to absorb acidity. The reserve alkalinity is frequently used for quality control during production and often listed in the specifications of the coolants. A fast and accurate determination is therefore important.This Application Note describes the straightforward determination of reserve alkalinity according to ASTM D1121. Using a fully automated system allows an accurate and reliable determination due to the reduction of human errors. Furthermore, the operator is free to carry out other tasks increasing the efficiency of the laboratory.

Boric acid is used in many primary circuits of nuclear power plants, in nickel plating baths, and in the production of optical glasses. Furthermore, boron compounds are found in washing powders and fertilizers. This bulletin describes the potentiometric and thermometric determination of boric acid. The determination also covers further boron compounds, when acidic digestion is applied.

This Bulletin describes three potentiometric, one photometric, one thermometric and one conductometric titration method for sulfate determination. The question of which indication method is the most suitable depends primarily on the sample matrix.Method 1: Precipitation as barium sulfate and back titration of the Ba2+ surplus with EGTA. Use of the ion-selective calcium electrode as indicator electrode.Method 2: As with Method 1, although with the electrode combination tungsten/platinum.Method 3: Precipitation titration in semi-aqueous solution with lead nitrate in accordance with the European Pharmacopoeia using the ion-selective lead electrode as indicator electrode.Method 4: Photometric titration with lead nitrate, dithizone indicator and the Optrode 610 nm, particularly suitable for low concentrations (up to 5 mg SO42- in the sample solution).Method 5: Thermometric precipitation titration with Ba2+ in aqueous solution, particularly suitable for fertilizers.Method 6: Conductometric titration with barium acetate in accordance with DIN 53127

This bulletin deals with the automated determination of calcium and magnesium in commercially available finished milk products using a 859 Titrotherm and a 814 USB Sample Processor. Calcium and magnesium in milk can be rapidly and easily titrated thermometrically using a standard solution of Na4EDTA as titrant.Thermometric titrations are conducted under conditions of constant titrant addition rate. The molarity of the titrant is computed automatically in tiamo (software) using the SLO command. Results are reported as mg Ca and Mg/100 mL.

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 describes the determination of the total acid number in various oil samples by catalytic thermometric titration as per ASTM D8045.

It is essential to know before starting the sample analysis if the electrode is in a good state or not. A well workingelectrode will increase the quality of your results, as the accuracy and precision will be increased. Furthermore, tedious error tracking can be omitted and no sample is wasted due to a defect or old electrode. There exist several ways how to check metal electrodes, e.g., measurement of redox potentials, potentiometric titration or bivoltammetric titration. This bulletin describes the best methods for the various by Metrohm available metal electrodes.

This Bulletin describes potentiometric titration methods for the determination of the acidity in milk and yoghurt according to DIN 10316, ISO/TS 11869, IDF/RM 150, ISO 6091 and IDF 86, the chloride content in milk, butter and cheese according to EN ISO 5943, IDF 88, ISO 15648, IDF 179, ISO 21422, and IDF 242. Additionally the determination of the sodium content in milk using the thermometric titration is described. The determination of the oxidation stability of butter in accordance to AOCS Cd 12b-92, ISO 6886 and GB/T 21121 as well as the determination of lactose in lactose free milk by ion chromatography is also described.For the determination of the pH value in dairy products see Application Bulletin AB-086 and for the determination of calcium and magnesium see Application Bulletin AB-235.

As the determination of the exact content of individual glycerides in fats and oils is difficult and time-consuming, several fat sum parameters or fat indices are used for the characterization and quality control of fats and oils. Fats and oils are not only essential for cooking, they are also an important ingredient in pharmaceuticals and personal care products, such as ointments and creams. Consequently, several norms and standards describe the determination of the most important quality control parameters. This Application Bulletin describes eight important analytical methods for the following fat parameters in edible oils and fats:Determination of water content in accordance with the Karl Fischer method; Oxidation stability in accordance with the Rancimat method; Iodine value; Peroxide value; Saponification value; Acid value, free fatty acids (FFA); Hydroxyl number; Traces of nickel using polarography; Special care is taken to avoid chlorinated solvents in these methods. Also, as many of the mentioned methods as possible are automated.

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.

The phosphoric acid content can be easily titrated with a standardized solution of 2 mol/L NaOH. The interfering calcium content in phosphoric fertilizer can be eliminated by adding a saturated oxalate solution.

This bulletin discusses automated determination of sodium in milk products available to the public using a 859 Titrotherm and a 814 USB Sample Processor. The sodium content of milk can be rapidly and easily titrated thermometrically with a standard solution of Al3+ as titrant. Thermometric titrations are conducted under conditions of constant titrant addition rate. The molarity of the titrant is computed automatically in tiamoTM (software) with the SLO command. Results are reported as mg Na/100 mL. In addition to this application bulletin, you can find more information on thermometric sodium determination in foods in our application video available on YouTube:https://youtu.be/lnCp9jBxoEs

In an acidic solution (containing NH4F * HF, Al(NO3)3 / KNO3) sodium forms NaK2AlF6 which precipitates in an exothermic solution, enabling analysis by thermometric titration. Several foods were analyzed, namely bouillon, gravy, tomato ketchup, corn chips, pretzel sticks as well as crackers. The reproducibility of the results was good. After weighing in and adding solutions, samples were crushed with a polytron to ensure homogeneity in the measuring solution. Relative standard deviations were between 0.08% and 3.75%. In addition to this application bulletin, you can find more information on thermometric sodium determination in foods in our application video available on YouTube:https://youtu.be/lnCp9jBxoEs

In titration, the titrant reacts with the analyte either exothermically (gives off heat) or endothermically (absorbs heat). The Thermoprobe measures the temperature change during titration. When all of the analyte has reacted with the titrant, the temperature of the solution will change, and the endpoint of the titration is indicated by an inflection in the temperature curve. Catalytically enhanced titrations using paraformaldehyde as catalyst are based on the endothermic hydrolysis of the paraformaldehyde in the presence of excess hydroxide ions. Edible oils are dissolved in a mixture of toluene and 2-propanol (1:1) and titrated with standardized TBAH (0.01 mol/L) in 2-propanol to a catalytically enhanced endpoint.

This bulletin deals with the automated determination of mixtures of HNO3, HF and H2SiF6 in the range of approximately 200-600 g/L HNO3, 50-160 g/L HF, and 0-185 g/L H2SiF6 using thermometric titration.Etch acid mixtures containing HNO3, HF and H2SiF6 from the etching of silicon substrates can be analyzed in a sequence of two determinations using the 859 Titrotherm. The first determination involves a direct titration with standard c(NaOH) = 2 mol/L, followed by a back titration with c(HCl) = 2 mol/L. This determination yields the H2SiF6 content plus a value for the combined (HNO3+HF) contents. The second determination consists of a titration with c(Al3+) = 0.5 mol/L to determine the HF content. For freshly made up mixtures of HNO3 and HF containing no H2SiF6, a linked two-titration sequence is employed. Results from the two determinations are used by tiamoTM to yield individual results for HNO3, HF and H2SiF6.

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.

Thermometric titration quickly and accurately assesses the total solids content of fluids employed in drilling oil and gas wells within minutes.

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

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.

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.

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.

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

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

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

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.