Kramer K, Lepschy J, Hock B
Technical University of Muenchen, Department of Botany, Freising, Germany.
J AOAC Int. 2001 Jan-Feb;84(1):150-5.
An enzyme-linked immunoassay (ELISA) was used for screening atrazine residues in soil. Samples were annually collected in Southern Germany between 1993 and 1998. An average of 419.5 samples was analyzed per year amounting to 2517 samples. The fraction of positive samples defined by atrazine concentrations >100 microg/kg soil decreased successively from 8% (corresponding to 33 samples) in 1993 to 0.6% (corresponding to 2 samples) in 1998. All positive samples and a selection of negative samples were subsequently validated by HPLC. Comparison of ELISA and HPLC data yielded correlation coefficient values of r = 0.958-0.981 (n = 18-47), except for 1995 when only a correlation of r = 0.864 (n = 18) was obtained. Four samples were overestimated and another 4 were underestimated with respect to the atrazine threshold value of 100 microg/kg soil as revealed by HPLC validation. Thus, 99.68% of 2,517 analyzed samples were correctly evaluated. The precision and reproducibility of the ELISA were adequate for a prescreening tool. The low cost per sample and the high sample throughput are not yet achievable by conventional analytical methods. The described combination of ELISA and HPLC has the potential to take advantage of both methods and to restrict determination errors to a minimum.
采用酶联免疫吸附测定法（ELISA）对土壤中的莠去津残留进行筛选。1993年至1998年期间，每年在德国南部采集样本。每年平均分析419.5个样本，共计2517个样本。以莠去津浓度>100微克/千克土壤定义的阳性样本比例从1993年的8%（对应33个样本）连续下降至1998年的0.6%（对应2个样本）。随后，所有阳性样本和部分阴性样本通过高效液相色谱法（HPLC）进行验证。ELISA和HPLC数据的比较得出相关系数值r = 0.958 - 0.981（n = 18 - 47），1995年除外，该年仅获得r = 0.864（n = 18）的相关性。HPLC验证显示，相对于100微克/千克土壤的莠去津阈值，有4个样本被高估，另有4个样本被低估。因此，在2517个分析样本中，99.68%得到了正确评估。ELISA的精密度和重现性对于预筛选工具而言是足够的。传统分析方法目前尚无法实现每个样本的低成本和高样本通量。所描述的ELISA和HPLC相结合的方法有潜力充分利用这两种方法，并将测定误差限制在最小程度。
