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Denatured fuel ethanol may contain additives such as corrosion inhibitors and detergents as well as contaminants from manufacturing that can affect the acidity of produced ethanol fuel. An increased acid content in solvents could lead to a variety of problems like a shorter storage stability or chemical corrosion. Using the Optrode with phenolphthalein as indicator, the acidity is determined as acetic acid by titration with sodium hydroxide as titrant.

Denatured fuel ethanol may contain additives such as corrosion inhibitors and detergents as well as contaminants from manufacturing that can affect the acidity of produced ethanol fuel. An increased acid content in solvents could lead to a variety of problems like a shorter storage stability or chemical corrosion.Using the dSolvotrode for indication, the acidity is determined as acetic acid by titration with sodium hydroxide as titrant.

Corrosion of metallic components is an inherent problem for engines, because metals naturally tend to oxidize in the presence of water and/or acids. Increased acid content is indicated by a low pH value, and could lead to a variety of problems like a shorter storage life (stability) or a reduced buffer capacity of the used engine coolant or antirust.In this Application Note, engine coolants or antirust samples are dissolved in water, and the pH measurement using the Profitrode is carried out according to ASTM D1287.

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.

The presence of acidic components in volatile solvents could be a result of contamination, decomposition during storage, distribution or manufacture. An increased acid content in solvents could lead to a variety of problems like shorter storage stability or chemical corrosion. Using the Optrode for indication, the acidity is determined by photometric titration with sodium hydroxide as titrant and phenolphthalein as indicator. If the volatile solvent is water soluble, it is dissolved in deionized water, if not, it is dissolved in carbon-dioxide free ethanol.

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.

The determination of the physical and chemical parameters as electrical conductivity, pH value, alkalinity, the calcium and magnesium hardness as well as the total hardness are necessary for evaluating the water quality. A fast and accurate determination in tap water is realized using an automated OMNIS System working in parallel on different workstations. An 856 Conductivity Module with Dosinos extends the system.

The bromine index is an important parameter for the determination of aliphatic C=C double bonds in petroleum hydrocarbons. For the titration, a solvent mixture of glacial acetic acid, methanol, and dichloromethane is usually used.In this Application Note, the chlorinated solvent in the solvent mixture was replaced with toluene, resulting in a more environmentally beneficial method in comparison to ASTM D2710 and IP 299.

The bromine index is an important quality control parameter for the determination of aliphatic C=C double bonds in aromatic hydrocarbons and is thus a measure for the presence of aliphatic unsaturation in these materials. In situ generated bromine reacts with the aliphatic double bonds. When the titration is finished an excess of free bromine causes a sudden change in the measured potential thus indicating the equivalence point.

The vaping and electronic cigarette industries have grown impressively in the past decade. The mixtures used in these products are usually called «e-liquid», «e-fluid», or «e-juice». To ensure the quality of these e-liquids, testing the most important quality parameters, such as nicotine content, is required. Nicotine in tobacco is usually determined by gas chromatography or liquid chromatography. Aqueous acid base titration is a much more affordable alternative for this determination. As e-liquids do not contain other components which might interfere with the titration, the aqueous acid base titration presented in this Application Note can be applied for nicotine determination. This method is an affordable and reliable way to determine the nicotine content in e-liquids and their nicotine starting material, ensuring the quality of these products.

Ethanol, bio-ethanol and biofuel (E85) are increasingly used as substitutes for petroleum-based fuels. During storage, they often come into contact with metallic substrates or surfaces, e.g., in barrels, tanks, or other containers. Excessive concentrations of ions in the stored fuel promotes corrosion. Monitoring the total concentration of the ions present in the fuel matrix should be the first step of an effective anti-corrosion strategy.An easy, fast, and cost-effective method to determine the total amount of ions is by measuring the electrical conductivity according to DIN 15938.

This Application Note presents a potentiometric titration method for a potassium bicarbonate and potassium carbonate assay meeting all USP General Chapter <1225> requirements.

The analysis of the reductants, free and total sulfurous acid, pH and total acidity of wine can be performed fully automated on an OMNIS system based on the directive OIV-MA-AS323-04B, OIV-MA-AS313-01 and OIV-MA-AS313-15.Added components like SO2 have preserving properties and affect the microbiological environment (anti-microbacterial and enzyme-deactivating), they trap fermentation byproducts such as acetaldehyde and suppress a coloring into brown. The bound and free sulfurous acid are in an equilibrium with each other and can be determined via iodometric titration. Iodometric titration is also the method of choice to quantify other reductants, such as dyes, tanning agents, degradation products of carbohydrates and ascorbic acid. Finally, the acidity of wine is an important quality parameter, which affects the color and taste of wines. The total acidity and the pH of wine can be determined on the same system. Hence, Metrohm offers an all-in-one solution for the analysis of these mentioned key parameters.

The FOS/TAC value, sometimes referred to as VFA/TA, is a meaningful parameter for assessing both the current condition and the development of anaerobic digestion processes in a digester of a biogas plant. Knowledge of this value can help decrease the risk of acidification problems, which can result in a costly crash of the entire digestion process. Therefore, an accurate and reliable determination of the FOS/TAC value is important for both efficient and cost-effective production operations. This value is determined by an acid-base titration. Using the Eco Titrator from Metrohm equipped with an Ecotrode plus electrode, a reproducible and accurate determination of the FOS/TAC value is possible.

Water treatment with ozone (O3) is a common procedure for the disinfection of swimming pools. It is important that a sufficient but not excessive amount of O3 is produced to disinfect the water. Otherwise, the remaining ozone could enter the swimming water, which could irritate the respiratory system or the skin of bathers.Ozone is also used in drinking and waste water treatment because it is significantly more effective than chlorine at inactivating or killing viruses and bacteria. This application note describes a method to determine the ozone concentration in water by potentiometric titration according to DIN 38408-3.

Nitrogen-based compounds are widely distributed in the environment and are essential growth nutrients for photosynthetic organisms. Therefore, it is important to monitor and control the amount of nitrogen compounds which are released into the environment.In this Application Note, a method to determine the nitrogen content in water by Kjeldahl digestion and distillation followed by a photometric or potentiometric titration according to ASTM D3590 is presented. The universality, precision, and reproducibility of the Kjeldahl method have made it the internationally recognized method for e.g. estimating the protein content in many matrices and it is the standard method to which all other methods are judged against.

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.

Lithium nitrate is an oxidizing agent used in the manufacture of red-colored fireworks and flares. In addition, the lithium nitrate trihydrate compound absorbs heat well and can be used for thermal energy storage. Since lithium nitrate is a hygroscopic substance, its purity must first be verified before it is used for synthesis or other applications. The purity assay is done by a fully automated precipitation titration between lithium and fluoride in an ethanolic solution. The benefit of titration is that the lithium nitrate does not need to be diluted after dissolving in ethanol as with other techniques such as ICP-MS.

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.

The lithium-ion battery market is continuously growing due to the tremendous demand for battery powered consumer products. So-called «NCMs», a mixture of nickel, cobalt, and manganese oxides, have been gathering interest as cathode materials, replacing traditional compounds like cobalt oxides.Quality analysis of the post-sintered materials or recycled batteries can be performed by titration, as demonstrated in this Application Note. A fully automated analysis of the corresponding metals can be performed with OMNIS and its pipetting equipment.

In order to consistently manufacture high quality baked goods, it is critical to measure the pH value and acidity content in the raw materials and during the production steps. These factors have a major influence on the taste and storage lifetime of the final product. Consistent product quality is only possible with precise measurements during the process.This Application Note describes the measurement of pH value and the total titratable acidity in flour, dough, and bread using the Eco Titrator from Metrohm.

If consumed in excess, sodium may damage the cardiovascular system. It is therefore in the interest of food manufacturers to reduce the salt content and while preserving the flavor of the food.To ensure consistent quality, it is critical to know the exact salt content in the raw materials and the final products. This is only possible by performing precise measurements during the production process.This Application Note explains the determination of sodium chloride in dough and bread quickly according to AOAC 971.27 with the Eco Titrator equipped with an Ag Titrode.

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

Traditional Chinese medicine (TCM) remedies are gaining popularity in other cultures. In some TCM, sulfur dioxide (SO2) is used as a preservative, antioxidant, and disinfectant. The products are treated by sulfurization with SO2 gas. However, sulfur dioxide is a very poisonous gas. Global health authorities have set strict limits for the content of SO2 in products. It is therefore of crucial importance to determine the sulfur dioxide content to comply with these limits. In this well-suited method, the SO2 content in different natural TCM products are analyzed reliably and accurately according to ISO 22590 using the Eco Titrator equipped with an Optrode and sodium hydroxide as titrant.

Electroplating processes are used in several different industry sectors to protect the surface quality of various products against corrosion or abrasion and significantly improve their working life. It is essential to check the bath composition on a regular basis to ensure that the process is operating correctly. Typical examples of electroplating baths include alkaline degreasing baths or acidic or alkaline baths containing metals e.g. copper, nickel, or chromium, or components like chloride and cyanide. It is crucial that the chosen analysis technique fulfills high safety standards for these kinds of analyses and produces reliable results. The OMNIS Sample Robot system automatically pipettes and analyzes aggressive electroplating bath samples on different workstations, increasing the safety in the lab. This provides more reliable results in comparison to manual titration and is more time efficient as different parameters can be analyzed in parallel.

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.

Many of the key factors that influence coffee taste correlate with chemical properties that can be measured. These include pH, titratable acidity, refractive index, and caffeine. Historically, many of these analyses have included long, manual sample preparation processes using the time-consuming, liquid chromatography (LC) technique. This Application Note looks at a faster, simpler, alternative method for analysis of key quality parameters in coffee using a single titration platform: OMNIS.

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.

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.

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.

About 20% of our sugar comes from sugar beet crops, mostly grown in Europe and the U.S. where the climate is temperate, whereas the other 80% is produced from sugar cane in tropical areas. Lime salts and pH are very important factors which are controlled during the sugar manufacturing process. Complexometric titration is often used to determine the concentration of lime salts in such kinds of samples. This Application Note presents a more robust method for determining calcium compounds in sugar beet juice. Subjectivity of color change determination is eliminated by using an ion selective electrode (ISE).

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.

Titration is an accurate and precise method that can be used to determine the pyrophosphate content in aqueous products. The OMNIS Titrator equipped with a dUnitrode delivers reliable determinations.

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.

The pH value in carbon black, an essential additive in modern lithium-ion batteries, is accurately and reliably analyzed in this Application Note by using the 913 pH Meter equipped with a Unitrode easyClean according to ASTM D1512 as well as ISO 787-9 and GB/T 1717-1986.

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.

Alkalinity defines the acid-binding capacity of natural water. A distinction is made between total alkalinity (m-value) and carbonate alkalinity (p-value). This Application Note presents the determination of pH and alkalinity in water with a titration method conforming to EPA 310.1, Standard Methods 2320 B (Titration Method), ASTM D1067, EN ISO 9963-1, and EN ISO 9963-2.

The amine value is an important parameter and quality indicator to determine in chemical processes and pharmaceuticals. This Application Note presents the nonaqueous perchloric acid titration of triethanolamine.

The total acid number (TAN) is an important parameter for assessing the acidity of oils and fuels. This Application Note determines TAN using conductometric titration.

Determination of nickel, zinc, iron(II), and manganese in lithium bromide using cation chromatography with UV/VIS detection (520 nm) after post-column reaction.

Determination of bromide and nitrate in 1% sodium chloride solution using anion chromatography with UV/VIS detection (205 nm) after chemical suppression.

Determination of glycolic and lactic acid in the presence of N-methyl pyrrolidone used in drug delivery systems using ion-exclusion chromatography with UV/VIS detection.

Determination of traces of fluoride, bromide, nitrate, phosphate, and sulfate using anion chromatography with conductivity detection after chemical suppression and subsequent UV/VIS detection.

Determination of iodate, chlorite, bromate, and nitrite using suppressed anion chromatography with UV/VIS detection after post-column reaction.

Determination of nitrite, nitrate, and phosphate in seawater from a shrimp farm using anion chromatography with conductivity detection after chemical suppression and subsequent UV/VIS detection.

Determination of N-acetylcysteine and phenylalanine in tablets against sinusitis by anion chromatography with UV/VIS detection according to USP.

Determination of traces of iodide in bottled water using anion chromatography with UV/VIS detection.