Flow-through fluorescence immunosensor for atrazine determination

A new flow-through fluoroimmunosensor for atrazine determination based on t he use of protein A immobilized on controlled pore glass as immunoreactor i s reported. The support, placed in the optical path of the flow cell, allow s the 'in situ' quantification of atrazine by on-line antigen-antibody bind ing upon successive injections of both substances. The immunosensor has a d etection limit of 2.1 mu g l(-1), a sample speed of about 10 samples per ho ur, and provides high reproducibility both within-day (3.2% for 5 mu g l(-1 ) and 2.2% for 30 mu g l(-1)) and between days. The optimum working concent ration range was 2.1-50 mu g l(-1). Possible interferences of other triazin es like simazine, desethylatrazine (DEA) and desisopropylatrazine (DIA) wer e evaluated. Simazine and DIA were not cross-reactive; however, the cross-r eactivity for DEA was CR = 7.7%. The proposed immunosensor was successfully applied to the determination of atrazine in drinking water and citrus frui ts. (C) 1998 Elsevier Science B.V. All rights reserved.