Development of antibodies for the detection of N-acetyl-glufosinate.
Glufosinate is a widely used herbicide, which is difficult to detect by conventional analytical techniques. For many other herbicides, suitable antibodies have been raised for immunoassay development. Unfortunately, glufosinate is a very small molecule and difficult to immunize with. Thus, a derivatization-assisted immunoassay (DAIA) using the target analyte N-acetyl-glufosinate (NAG) was constructed. The activated hapten was synthesized by a new approach, using a homobifunctional cross-linker suberic acid bis(N-hydroxysuccinimide ester). The preparation of a suitable conjugate, the immunization, and the characterization of polyclonal antibodies are shown. The determination of the conjugation density (hapten density) of the immunogens was performed by four different methods (high-performance liquid chromatography with a refractive index detector, total reflection X-ray fluorescence, inductively coupled plasma mass spectrometry, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry), which gave similar results. The limit of detection was 17 mug/L NAG in water for the direct competitive enzyme immunoassay. NAG is also a main metabolite of glufosinate in resistant transgenic plants. The antibodies might be useful for the selective detection of NAG in the presence of the parent compound glufosinate (cross-reactivity 0.13%) and other metabolites.
Institute of Hydrochemistry, Technische Universität München, Marchioninistrasse 17, D-81377 München, Germany. michael.weller@ch.tum.de
Michael G
MG
Weller
Marcus
M
Diemer
Carola
C
Wersching
Reinhard
R
Niessner
Heinz
H
Sochor
D000107:Acetylation; D000613:Aminobutyrates / Q000032:analysis / Q000378:metabolism; D000818:Animals; D000906:Antibodies / Q000276:immunology; D006241:Haptens / Q000737:chemistry / Q000276:immunology; D006433:Hemocyanins / Q000276:immunology; D006540:Herbicides / Q000032:analysis*; D007106:Immune Sera / Q000096:biosynthesis*; D007114:Immunization; D007118:Immunoassay; D007124:Immunoenzyme Techniques; D008297:Male; D011786:Quality Control; D011817:Rabbits; D013237:Stereoisomerism
D000613:Aminobutyrates; D000906:Antibodies; D006241:Haptens; D006540:Herbicides; D007106:Immune Sera; C003121:phosphinothricin; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin