Verebey K, DePace A
New York State Division of Substance Abuse Services, Testing and Research Laboratory, Brooklyn.
J Forensic Sci. 1989 Jan;34(1):46-52.
A rapid gas-liquid chromatographic (GLC) method was developed for the confirmation of benzoylecgonine (BE) positive urine samples screened by the enzyme multiplied immunoassay technique (EMIT) assay. The procedure is performed by solvent extraction of BE from 0.1 or 0.2 mL of urine, followed by an aqueous wash of the solvent and evaporation. The dried residue was derivatized with 50 microL of pentafluoropropionic anhydride and 25 microL of pentafluoropropropanol at 90 degrees C for 15 min. The derivatizing reagents were evaporated to dryness, and the derivatized BE, and cocaine if present, were reconstituted and injected into the gas chromatograph. The column was a 15-m by 0.2-mm fused silica capillary column, coated with 0.25 micron of DB-1, terminating in a nitrogen phosphorus detector (NPD). Cocaine and the pentafluoro BE derivatives retention times were 3.2 and 2.6 min, respectively. Nalorphine was used as reference or internal standard with a retention time of 4.78 min. The complete procedure can be performed in approximately 1.5 h. The EMIT cutoff between positive and negative urine samples is 300 ng/mL of BE. The lower limit of sensitivity of this method is 25 ng of BE extracted from urine. Validation studies resulted in confirmation of 101 out of 121 EMIT cocaine positive urine samples that could not be confirmed by thin-layer chromatography (TLC). This represents 84% confirmation efficiency.
开发了一种快速气-液色谱（GLC）方法，用于确证经酶放大免疫分析技术（EMIT）筛查呈苯甲酰芽子碱（BE）阳性的尿样。该程序通过从0.1或0.2 mL尿液中溶剂萃取BE来进行，随后用水洗涤溶剂并蒸发。干燥后的残渣在90℃下用50微升五氟丙酸酐和25微升五氟丙醇衍生化15分钟。将衍生化试剂蒸发至干，将衍生化的BE以及如有存在的可卡因重新溶解并注入气相色谱仪。色谱柱为15 m×0.2 mm的熔融石英毛细管柱，涂覆0.25微米的DB-1，连接氮磷检测器（NPD）。可卡因和五氟BE衍生物的保留时间分别为3.2分钟和2.6分钟。烯丙吗啡用作参比物或内标，保留时间为4.78分钟。整个程序大约可在1.5小时内完成。EMIT对尿样阳性和阴性的截断值为300 ng/mL的BE。该方法的最低检测限是从尿液中萃取25 ng的BE。验证研究证实了121份经EMIT检测为可卡因阳性但无法用薄层色谱法（TLC）确证的尿样中的101份。这代表确证效率为84%。
