Summary The non-volatile matter test principle of purified water is to detect the mass of non-volatile matter solids obtained after 100mL of purified water is evaporated and dried. The difficulty is that testers need to perform repeated operations to achieve the 0.3mg constant weight value required by the Chinese Pharmacopoeia. The traditional test method has the disadvantages of low efficiency and manual on-duty. After long-term practice and repeated verification, it adopts an integrated and automated structural design, equipped with rapid water bath evaporation and gas balance technology, which can realize automatic feeding, water bath evaporation, blast drying, and cooling. Balance, constant temperature and weighing five in one fully automatic test. Through repeated experiments and gradient design experiments, the results show that: 2 rounds of weighing can reach a constant weight error of 0.3mg, and when the amount of scalar addition is 9.4mg/100mL, the precision (RSD) is 0.73%, and the accuracy of the gradient design experiment is high. There is no bias between parallel samples. Conclusion: After the innovation of the non-volatile detection technology of purified water, the constant weight time is short, the operation is simple, and the data accuracy and precision are good. Key words: purified water; non-volatile matter; constant weight; automated testing In the production of pharmaceuticals, purified water is widely used as solvents, detergents, auxiliary materials, raw materials for pure steam and water for injection, etc., from raw materials to preparations, the use of purified water runs through the entire production process. Therefore, the quality control of purified water is very important in the production management of pharmaceutical companies. The test of non-volatile matter in purified water is one of the basic inspection items. The difficulty lies in the 0.3mg constant weight value required by the Chinese Pharmacopoeia. Experimental stop condition. Traditional testing methods have disadvantages such as low efficiency, repetitive and cumbersome operations, difficulty in constant weight, and the need for manual supervision. Domestic and foreign standard requirements According to the requirements of "Purified Water" in the second part of the Chinese Pharmacopoeia 2020 edition: take 100mL of this product, put it in an evaporating dish with a constant weight at 105°C, evaporate it to dryness on a water bath, and dry it to a constant weight at 105°C. The remaining residue should not exceed 1mg. The definition of constant weight in the Chinese Pharmacopoeia is constant weight, unless otherwise specified, refers to the weight of the test sample whose weight difference is less than 0.3 mg after two consecutive dryings or igniting; the second time of drying to constant weight And every subsequent weighing should be carried out after continuing to dry for 1 hour under the specified conditions. See Table 1 for the requir...
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