Zeta电位法研究除草剂在土壤胶体中的吸附

应用Zeta(ζ)电位法研究比较了扑草净和扑灭通在4种土壤胶体中的吸附.结果表明,当带有正电荷的除草剂在负电荷土壤表面吸附后,土壤表面的ζ电位有所增加,甚至使ζ电位从负转变成正.通过零电荷点计算得到除草剂和土壤之间的吸附常数和Gibbs自由能,并由经典的振荡平衡法得到相近结果.     

Evaluation of atrazine positive and false positive immunoassay detections in ground water

Abstract

False positive responses on an atrazine (6‐chloro‐N‐ethyl‐N'‐(l‐methylethyl)‐1, 3, 5‐triazine‐2, 4‐diamine) immunoassay kit were investigated to explain possible causes for these occurences. Ground water samples were evaluated with the immunoassay kit and positive responses (>0.20 μg L^‐1) were confirmed using gas chromatography/mass spectrometry (GC/MS). Non‐confirming samples (false positives) were analyzed for seven additional compounds on GC. Resulting GC/MS and GC analyses showed that 70% of the false positives could be attributed to two compounds. Prometon (6‐methoxy‐N,N'‐bis(l‐methylethyl)‐1, 3, 5‐triazine‐2, 4‐diamine) was responsible for the majority (64%) of the false positive responses The atrazine metabolite, deethylatrazine (2‐chloro‐4‐amino‐6‐isopropylamino‐1, 3, 5‐triazine), was responsible for the other 6% of the false positives measured. Unattributed false positives (30%) were probably due to an overestimation of pesticide concentrations in the kit's lower detection range.