Developtment of sensitive and rapid methods for analysis of inorganic toxic substances in human specimens

1998年7月25日，发生了“和歌山咖喱事件”，造成63人因砷中毒受伤，4人死亡。同年，许多使用其他无机毒素的模仿中毒事件紧随其后。因此，我们必须准备好应付包括无机毒物在内的任何类型的毒物分析。我们介绍了一套完整的离子色谱系统和一个自动抑制器，它可以覆盖几乎所有类型的无机化合物的分析。作为首次使用上述仪器的研究，我们建立了一套详细的分析人体全血中亚硝酸盐和硝酸盐阴离子的程序。全血中亚硝酸盐阴离子的测定存在一个严重的问题，因为亚硝酸盐的停留时间与全血中大量存在的氯阴离子的停留时间非常接近。在将样品应用于离子色谱之前，我们使用On Guard II AG和On Grand II h的组合药盒成功地去除了氯阴离子，发现全血中大部分亚硝酸盐在3小时内被氧化为硝酸盐。全血亚硝酸盐回收率达90%以上。在全血50 ~ 100 μg/ml范围内呈线性关系。硝酸盐的检出限足够低。这些数据被整理成一篇科学论文，目前正在一家国际期刊上出版。2)电磁共振分析锰（Mn）、钼（Mo）、硫氰酸盐等无机物离子经过适当的预处理，尝试用电磁共振法测定。锰离子具有顺磁性，因此只有在询问样品后才能用ESR测量。Mo离子与二乙基二硫代氨基甲酸酯反应后，草酸还原后的配合物可以用ESR测定，灵敏度高。硫氰酸盐也可以在络合物形成后进行测定。这些结果发表在分析期刊上。

1)Ion chromatographic analysis of inorganic toxic substancesOn July 25, 1998, the Wakayama Curry Incident, in which 63 people were injured by arsenic and 4 killed, took place. In the same year, many copycat poisoning incidents using other inorganic toxins followed. Therefore, it was essential for us to be prepared to cope with any type of poison analysis including inorganic ones. We introduced a full system of ion chromatography with an autosuppressor, which could cover the analysis of almost every type of inorganic compounds. As the first study using the above instrument, we established a detailed procedure for analysis of nitrite and nitrate anions in human whole blood. There was a serious problem in the assays of nitrite anion in whole blood, because the retention time of nitrite was very close to that of chloride anion which is abundantly present in whole blood. Before application of a sample to ion chromatography, we succeeded in removing the chloride anion using the combination of cartridges of On Guard II AG and On Grand II H. It was found that most of nitrite was oxidized to nitrate within 3 h in whole blood. The recovery rate for nitrite from whole blood was more than 90 %. The linearity was confirmed in the range of 50-100 μg/ml of whole blood. The detection limit of nitrate was sufficientry low. These data were arranged into a scientific paper, which is now in press in an international journal.2)ESR analysis of inorganic substancesIons of manganese(Mn), molybdenum(Mo) and thiocyanate were tried to be measured by ESR after suitable pretreatments. Mn ion shows paramagnetic property and was thus measurable by ESR only after asking a sample. Mo ion reacted with diethyldithiocarbamate and the complex could be measured by ESR with high sensitivity after reduction by oxalic acid. Thiocyanate could be also measured after complex formation. These results were published in analytical journals.