Tar or bitumen samples contain a certain amount of moisture mixed inhomogeneously. In order to measure moisture content in such samples, it requires sonication and extraction using dehydrated THF (tetrahydrofuran) as extraction solvent for pretreatment prior to titration. In addition, by using the KF titrator in combination with the oil evaporator EV-2000L by azeotropic distillation method, a successful measurement of water in tar can be made without any interference by coexisting substances may bother KF reaction.

Water confectionery product containing sugar can be determined by Direct titration with　AQUACOUNTERⓇ AQV-2100 /AQV-300.

Chicken oil is not soluble in methanol but well soluble in chloroform or toluene. In Karl Fischer titration method, it is a key to find a suitable solvent to dissolve the sample and to extract water contained. This application note introduces two methods: one is directly inject the sample into chloroform-base solvent, and the other is using an oil evaporator to azeotropically remove the water from the sample and then deliver it into the titration cell.

Water in butter oil can be determined by direct volumetric Karl Fischer titration. Using a mixture of methanol and chloroform as solvent is recommended to help the sample dissolved well in to the solvent for more accurate measurements.

This application method is applicable for the determination of water in alcohols. However, this method can be used for many kinds of the organic solvents.

Water in resins can be determined by heat evaporation indirect titration with Coulometric Karl Fischer titrator AQ-2100/AQ-300 interfaced with Solid Evaporator EV-2000. By heating the sample at near its melting point, only water is evaporated and carried into the titration cell to be measured. This system is very effective to keep the anode solution in the cell and reduce the consumption of expensive KF reagents.

Water in cosmetic cream can be determined directly by volumetric Karl Fischer titration using AQUACOUNTER® AQV-2100 or AQV-300. For greasy and high viscosity samples, an optional sampling tool can easily measure water in sugar paste for confectionery with high accuracy and repeatability.

The determination of water in 2-propanol is very straightforward. In this application note, the volumetric method is applied because the water content is relatively high (% level). Some grades of 2-propanol contain very low water content (ppm level), recommendable to use coulometric KF titration method.

本文采用库仑法的卡尔费休水份滴定的方法测定试剂中水份，结果准确，重复性好！且简单、快速、灵敏、准确。

无机盐是基础原料、材料工业产品，用途广、需求量大。其用途涉及到造纸、橡胶、塑料、农药、饲料添加剂、微量元素肥料、空间技术、采矿、采油、航海、高新技术领域等各个方面。

文章主要介绍了天美仪器检测蜜饯中防腐剂、糖精钠、农残、添加色素等物质的检测方案和仪器配置，可以供蜜饯生产企业或检测监管机构参考。

The quantities of sulfuric acid and copper contained in CuSO4 plating solution can be determined consecutively by using the COM-potentiometric Titrator with additional burets and suitable electrodes. Sulfuric acid is titrated with sodium hydroxide titrant first. And then potassium iodide is added in the status acidified by sulfuric acid to liberate iodine. The free iodine is finally titrated with sodium thiosulfate titrant to measure copper contained.

On of the most typical and popular method for quantification of high-concentration salt in soy sauce or seasoning oils and sauces is the silver nitrate titration. The sample is titrted with silver nitrate titrant solution after acidifying the sample with nitric acid to mask carbonate, etc. Cl- + AgNO3 􀃆 AgCl + NO3-

unitAfter acidifying a sample solution with hydrochloric acid, dispense iodine solution and leave it for 30 minutes in a dark place. And then remaining iodine is quantified by back titration with Na2S2O3titrant.

The quantifications of total chromium (A) and chromic acid (B) can be carried out as described in this application note following the calculation formulae below. The amount of chromic anhydride can be obtained by subtracting the quantity of chromic acid from the blank test result (C). Chromic anhydride = (C) – (B) Trivalent chromium = (A) – (B)

The amount of chloride ions contained in concrete process water is strictly reduced to maintain the strength as construction materials. When the estimated concentration of chloride ion is a few ppm, using an organic solvent as titration solvent would be effective to sharpen the inflection point.

Polyurethane has an excellent flexibility, adhesiveness and high impregnation rate, widely utilized such as automotive films, insulating materials, and paints. The polyurethane resin is a polymer which involves the urethane bond, obtained by the polymerization reaction between polyisocyanate and polyol (also called, polyester or polyether). ･･･ ―NCO + HO― ･･ 􀃆 ･･ ―NHCOO― ･･･ (1) There are several different test methods for measuring hydroxyl groups (-OH) of polyols. In this application note, the test method using pyridine solution containing phthalic anhydride is applied to the polyol sample. The hydroxyl number is expressed as milligrams (mg) of potassium hydroxide as equilibrium amount of hydroxide groups contained in 1g of sample.

Polyurethane has an excellent flexibility, adhesiveness and high impregnation rate, widely utilized such as automotive films, insulating materials, and paints. The polyurethane resin is a polymer which involves the urethane bond, obtained by the polymerization reaction between polyisocyanate and polyol (also called, polyester or polyether). ･･―NCO + HO―･･ 􀃆 ･･―NHCOO― … (1) ―NCO + H2N―･･ 􀃆 ･･―NHCONH― … (2) ･･H2N―(excessive) + HCl 􀃆 HCl・H2N― … (3) (B－D)×K×F×M S×1000 A1 ： Content of isocyanate groups (%) F ： Factor of the titrant D ： Volume of the titrant consumed (mL) M ： Molarity of the titrant (0.5) B ： Blank value (mL) S ： Weight of the sample added (g) K ： Formula weight of isocyanate (42.02)

铬虽然是人体必需的一种微量元素，但是铬过量摄入对人体造成的危害非常大。其毒性与存在的价态有关，而三价铬的毒性在人体里就很容易显现。如果人体长期大量摄入三价铬，那么会影响身体的抗氧化系统，容易得一些慢性的氧化性的疾病，比如说糖尿病、高血压这一类的疾病。另外，由于人体的抗氧化系统受到了损伤，容易发生肿瘤等这种异常增生的疾病。 明胶胶囊做为药品的罐装材料，由于非法生产商采用工业明胶作原料，导致药用胶囊重金属铬超标，对人民的健康造成危害，因此对胶囊中铬的含量的测定是十分必要的。本实验依据2010版药典中明胶用胶囊的相关规定进行，AA6100原子吸收石墨炉测定数据稳定。

Lubricant that is used in compressors of freezer or cooler circulates the cooling circuit with the coolant (CFC-type coolant). The chlorine ion contained such lubricant and coolant may corrode the internal surface of piping and cause failure. This section introduces an example in which approximately 20g of sample was weighed precisely and dissolved in 100mL solvent mixture to be acidified with nitric acid for potentiometric titration with silver nitrate titrant. Cl-+ AgNO3 ———􀃆 AgCl + NO3- The amount of chlorides in freezer oils can be determined by silver nitrate titration method by dissolving the sample in organic solvents acidified with nitric acid.

Amino nitrogen is in powdered soup stock is measurable by Formol titration that is known as a simplified method. Adding hot water to dissolve the sample and to extract amino nitrogen, cool it to room temperature. After titrating at pH 8.4 by 0.1mol/L NaOH titrant, neutral formalin is added and continue the titration to pH8.4 again to measure amino nitrogen in the sample.

Acidity and vitamin C in refreshing drinks are titrated successively to quantify each component. (1) First, citric acid in the sample is titrated with sodium hydroxide using glass/reference combination electrode. CH2COOH CH2COONa C(OH)COOH + 3NaOH 􀃆 C(OH)COONa + 3H2O CH2COOH CH2COONa (2) When titration of citric acid is completed, acetic acid is added to acidify the sample. The indicator electrode is switched to platinum electrode automatically and vitamin C is titrated with iodine. + I2 􀃆 + 2HI

Sodium chloride contained in immunogloblin can be easily determined by precipitation titration method. Cl- + AgNO3 􀃆 AgCl + NO3-

H2SO4is quantified by titrating with NaOHbased on a neutralization reaction as below. H2SO4＋2NaOH　→　Na2SO4＋2H2O CuSO4 ･ 5H2O is quantified by titrating with EDTA titrant based on the following chemical reaction. Cu (II) + EDTA 􀃆 Cu-EDTA CuSO4･5H2O is quantified by titrating with EDTA titrant based on the following chemical reaction. 　　　　　　 Cu (II) + EDTA 　􀃆　Cu-EDTA ......

Copper ion (Cu2+) contained in the etching solution is quantified using chelatometric titration method based on chemical reaction shown below. The AQUACOUNTER’s COM series Titrator with Photometric unit is provided with an optical probe and optimum filter. The effect of acidic compounds contained in etching treatment solution becomes deteriorated with repeated use in process. In this application, the sample may contain mainly the following two acidic compounds: sulfuric acid and ammonium hydrogen fluoride, three inflection points will appear in the measurement of used etching solution. By linking three condition files, a sequential titration can be performed to detect all end points. Hydrogen peroxide is contained in etching solutions as the surface treatment solution for copper foil on printed circuit boards, and it acts as oxidant or reductant depending on the compound it reacts with. The amount of the hydrogen peroxide can be determined by a typical redox titration with potassium permanganate titrant.

Free alkali compounds in hair coloring products can be determined by dissolving the sample well in a mixture of water and methanol and titrating with HCl titrant based on the acid/base titration method.

For the determination of vitamin C, there are two main methods; iodine titration method and indophenol method. In this application note, vitamin C is quantified by titrating with indophenol titrant after acidifying the sample with a mixture of metaphosphoric acid and acetic acid solution. The end point will be determined in the presence of an excess of indophenol, at the moment where the color of the solution changes from blue to red. This color change is detected photometrically in this measurement. Citric acid contained in fruit juice is quantified by acid/base titration with sodium hydroxide. The chemical reaction occurring in this titration is shown by the following formula.

Copper ions in industrial waste is determined by titration with EDTA using copper ion-selective electrode. Since the estimated amount of copper ions in the sample is very low, the standard addition method is applied to this measurement.

Chloride ions in well water is determined by titrating with silver nitrate using the COM series potentiometric Titrator with the silver electrode. The end point is automatically detected at the largest inflection point.

Citric acid contained in fruit juice (apricot in this application) is determined by acid/base titration with sodium hydroxide. When pulp is mixed in the samples, grind it prior to titration. CH2COOH CH2COONa | | C(OH)COOH + 3NaOH 􀃆 C(OH)COONa + 3H2O | | CH2COOH CH2COONa