Moriya F, Hashimoto Y, Kuo T L
Department of Legal Medicine, Kochi Medical School, Japan.
J Anal Toxicol. 1999 May-Jun;23(3):210-5. doi: 10.1093/jat/23.3.210.
This paper describes the tissue distributions of dichlorvos, an organophosphate, and chlorpyrifos-methyl, an organophosphorothioate, in a male individual who died after ingesting an insecticidal preparation containing these chemicals and the results of an in vitro stability study on dichlorvos and chlorpyrifos-methyl in blood and buffers. Tiny amounts of dichlorvos, 0.067 and 0.027 mg/L, were detected in the vitreous humor and cerebrospinal fluid, respectively. Although dichlorvos (0.082-8.99 mg/L or mg/kg) was detected in the thoracic aortic blood, thoracic inferior vena caval blood, pericardial fluid, bile, and spleen, it was strongly suggested that it had diffused postmortem from the stomach, which contained 879 mg, because no dichlorvos was detected in the other blood samples and tissues tested. Substantial amounts (0.615-4.15 mg/L) of chlorpyrifos-methyl were detected in all blood samples, and the order of its concentrations was as follows: pulmonary vessel blood > thoracic inferior vena caval blood > blood in the right cardiac chambers > blood in the left cardiac chambers approximately thoracic aortic blood > right femoral venous blood. The total amount of chlorpyrifos-methyl in the stomach was 612 mg. However, it was strongly suggested that virtually no chlorpyrifos-methyl diffused from the stomach into surrounding fluids and tissues postmortem because no chlorpyrifos-methyl was detected in the bile and little was found in the pericardial fluids. Neither compound was detected in the urine. In vitro experiments showed that dichlorvos (10 mg/L) almost disappeared from fresh (pH 7.4) and acidified (pH 6.2) blood samples within 24 and 72 h, respectively. However, 53 and 77% of the original amount of dichlorvos in 0.05M phosphate buffers at pH 7.4 and 6.2 were detected 72 h later. Chlorpyrifos-methyl (1 mg/L) was very stable in blood samples, regardless of the pH, during the 72-h study period, but in the pH 7.4 and 6.2 phosphate buffers, approximately 80% of the original amount had degraded after 72 h. These results indicate that organophosphates are degraded more rapidly by esterase activities than by chemical mechanisms and that organophosphorothioates are hydrolyzed chemically in aqueous solutions but are very stable in biological specimens and not metabolized by esterases. When sodium fluoride was added to blood samples, dichlorvos degraded completely within 15 min, and chlorpyrifos-methyl became very unstable. Thus, when analyzing samples to detect organophosphorus chemicals, this common preservative should not be added to fluid specimens.
本文描述了一名男性个体摄入含有敌敌畏（一种有机磷酸酯）和甲基毒死蜱（一种硫代磷酸酯）的杀虫制剂后死亡，这两种物质在其体内的组织分布情况，以及敌敌畏和甲基毒死蜱在血液和缓冲液中的体外稳定性研究结果。在玻璃体液和脑脊液中分别检测到微量的敌敌畏，含量为0.067毫克/升和0.027毫克/升。虽然在胸主动脉血、胸下腔静脉血、心包液、胆汁和脾脏中检测到了敌敌畏（0.082 - 8.99毫克/升或毫克/千克），但强烈提示其是死后从含有879毫克敌敌畏的胃中扩散而来，因为在其他检测的血液样本和组织中未检测到敌敌畏。在所有血液样本中均检测到大量的甲基毒死蜱（0.615 - 4.15毫克/升），其浓度顺序如下：肺血管血＞胸下腔静脉血＞右心腔血液＞左心腔血液≈胸主动脉血＞右股静脉血。胃中甲基毒死蜱的总量为612毫克。然而，强烈提示死后甲基毒死蜱几乎没有从胃扩散到周围的液体和组织中，因为在胆汁中未检测到甲基毒死蜱，在心包液中也仅发现少量。尿液中未检测到这两种化合物。体外实验表明，敌敌畏（10毫克/升）在新鲜（pH 7.4）和酸化（pH 6.2）的血液样本中分别在24小时和72小时内几乎完全消失。然而，在pH 7.4和6.2的0.05M磷酸盐缓冲液中，72小时后仍检测到原始敌敌畏量的53%和77%。在72小时的研究期间，甲基毒死蜱（1毫克/升）在血液样本中无论pH如何都非常稳定，但在pH 7.4和6.2的磷酸盐缓冲液中，72小时后约80%的原始量已降解。这些结果表明，有机磷酸酯通过酯酶活性降解的速度比通过化学机制更快，而硫代磷酸酯在水溶液中通过化学水解，但在生物标本中非常稳定，且不被酯酶代谢。当向血液样本中添加氟化钠时，敌敌畏在15分钟内完全降解，甲基毒死蜱变得非常不稳定。因此，在分析检测有机磷化学物质的样本时，这种常用防腐剂不应添加到液体标本中。
