New Approach for Analysis of Amphetamines in Urine

Abstract

       Analytical results of amphetamines in urine are significant evidence of the legal proceedings. The methods used in the analysis must be highly effective. Bureau of Drug and Narcotic developed two fast, accurate and precise gas chromatography–mass spectrophotometry (GC-MS) and liquid chromatography - mass spectrophotometry (LC-MS) methods for qualitative and quantitative determination of amphetamines in urine. Amphetamines were extracted from urine by solid phase extraction method. The proposed method proved to be specific and selective without interference from urine matrixes. For GC-MS method, the linearity and range were 100-4,000 nanograms per milliliter for amphetamine and methamphetamine with correlation coefficients greater than 0.99. Mean percentage recoveries for amphetamine and methamphetamine were 75.40 and 76.89, respectively. Inter-day accuracy for all drugs range from 0.34 to 17.23 % RD. Inter-day precision for all drugs range from 3.84 to 12.57 % CV. The uncertainties at a confidence level of 95 were 2.00 ± 0.39 micrograms per milliliter and 2.00 ± 0.35 micrograms per milliliter, respectively. For LC-MS techniques, the linearity and range were 300-2,000 nanograms per milliliter for amphetamine and methamphetamine with correlation coefficients greater than 0.99. Inter-day accuracy for all drugs range from 2.22 to 16.11 % RD. Inter-day precision for all drugs range from 2.36 to 10.43 % CV. The uncertainties at a confidence level of 95 were 2.00 ± 0.27 micrograms per milliliter and 2.00 ± 0.24 micrograms per milliliter, respectively. The unit cost of material cost for the analysis by GC-MS and LC-MS are 628 baht and 438 baht, respectively. Therefore, the developed methods are applicable for analysis of amphetamines in urine with in the assigned level of narcotic acts.