Distribution of methamphetamine concentration in saliva and urine samples and the analysis of the initial screening / 中国法医学杂志

Objective To obtain methamphetamine concentration profiles in saliva and urine samples of drug addicts and to screen the colloidal gold strip. Methods Methamphetamine concentration in saliva and urine samples of drug addicts was determined by liquid chromatography tandem mass spectrometry. The initial screening was obtained by colloidal gold strip test. The results were compared and analyzed. Results using the method of protein and fluid MRM scan method to detect direct precipitation, saliva is linear in the range of 1~100ng/mL, the linear correlation coefficient is 0.9987, the detection limit is 0.1ng/mL, the limit of quantification was 1ng/mL, the urine is linear in the range of 1~100ng/mL, the linear correlation coefficient is 0.9943, the detection limit is 0.5ng/mL, the limit of quantification was 1ng/mL. Saliva and urine samples diluted, the concentration in the linear range. Saliva and urine samples of four types of methamphetamine colloidal gold reagent strip were screened directly, and the results were judged visually. Conclusion the detection rate of colloidal gold strip is about 79%, the detection rate of saliva is about 81%, and the detection rate can be increased to more than 93% by using two reagent strips. Combined with the initial screening results and the instrument confirmation concentration, it can be found that the gray zone setting and sensitivity setting have certain influence on the detection rate, and it is suggested to improve the sensitivity to meet the needs of screening.

Determination of dexamethasone in human plasma by solid phase extraction with ultra performance liquid chromatography-tandem mass spectrometer / 中国法医学杂志

Objective To develop the analytical method to determine the content of dexamethasone in human plasma by solid phase extraction with ultra performance liquid chromatography-tandem mass spectrometer. Methods The human plasma was extracted with a solid phase extraction(SPE) and determined by UPLC-MS/MS. LC-MS/MS was performed in ESI source with MRM mode for quantification. Results The lowest detectable limit was 0.05ng/mL, the linear range was 1~100ng/mL. The absolute recovery was more than 78.1%. The intra- and inter day precision was within 15% at three concentrations. Conclusion Since the procedure proved to be simple, quick and effective, it could be used for the determination of dexamethasone in human plasma.