A new, versatile field immunosensor for environmental pollutants: development and proof of principle with TNT, diuron, and atrazine.
This paper presents a new, versatile, portable miniaturized flow-injection immunosensor which is designed for field analysis. The temperature-controlled field prototype can run for 6h without external power supply. The bio-recognition element is an analyte-specific antibody immobilized on a gold surface of pyramidal structures inside an exchangeable single-use chip, which hosts also the enzyme-tracer and the sample reservoirs. The competition between the enzyme-tracer and the analyte for the antigen-binding sites of the antibodies yields in the final step a chemiluminescence signal that is inversely proportional to the concentration of analyte in the given range of detection. A proof of principle is shown for nitroaromatics and pesticides. The detection limits (DL; IC20) reached with the field prototype in the laboratory was below 0.1 microg l(-1) for 2,4,6-trinitrotoluene (TNT), and about 0.2 microg l(-1) for diuron and atrazine, respectively. Important aspects in this development were the design of the competition between analyte and enzyme-tracer, the unspecific signal due to unspecific binding and/or luminescence background signal, and the flow pattern inside the chip.
Ciumasu
Ioan M
IM
Technical University Munich, Chair of Ecological Chemistry and Environmental Analysis, Weihenstephaner Steig 23, 85350 Freising-Weihenstephan, Germany.
Krämer
Petra M
PM
Weber
Cristina M
CM
Kolb
Gunther
G
Tiemann
David
D
Windisch
Stefan
S
Frese
Ines
I
Kettrup
Antonius A
AA
D001280:Atrazine / Q000032:analysis*; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004237:Diuron / Q000032:analysis*; D004784:Environmental Monitoring / Q000295:instrumentation* / Q000379:methods; D004787:Environmental Pollution / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D017022:Flow Injection Analysis / Q000295:instrumentation / Q000379:methods; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods; D014303:Trinitrotoluene / Q000032:analysis*
D014303:Trinitrotoluene; D004237:Diuron; D001280:Atrazine