Preliminary evaluation of a lateral flow immunoassay device for screening urine samples for the presence of sulphamethazine.
A lateral flow immunoassay (LFIA) device was developed and applied to testing urine samples for residues of the antimicrobial sulphamethazine (SMZ). This report describes the preparation of a rat monoclonal antibody to SMZ and its characterisation in an ELISA format. Apart from SMZ, the antibody showed high (> or =50%) cross-reactivity to N4-acetyl-sulphamethazine (55%), sulphamerazine (59%) and sulphisoxazole (50%) and lower cross-reactivity of 18% to sulphachlorpyridazine and sulphadiazine. The LFIA device consisted of a nitrocellulose membrane spotted with SMZ-ovalbumin and goat anti-mouse antibody as capture line and control line, respectively. Mouse anti-rat IgG F(ab')2 fragment specific antibody, adsorbed to colloidal carbon, was used as the detection ligand in the LFIA. The LFIA device had a cut-off value of 6.3 ng/ml in diluted (1/10) urine. Urine samples from SMZ-treated pigs, and bovine and porcine urine samples fortified with SMZ were used for a blind, four-laboratory evaluation of the performance of the LFIA device. Concentrations of SMZ in the test samples (n=29), as determined by LC-MS/MS, ranged from 0 (<3) to 1174 ng/ml. The evaluation of the LFIA device showed an overall sensitivity of 100%, a specificity of 71%, and positive and negative prediction values of 73% and 100%, respectively. The LFIA device has been fabricated as a test kit for determining SMZ residues in animals produced for slaughter.
O'Keeffe
M
M
The National Food Centre, Teagasc, Dunsinea, Castleknock, Ashtown, Dublin 15, Ireland. mokeeffe@nfc.teagasc.ie
Crabbe
P
P
Salden
M
M
Wichers
J
J
Van Peteghem
C
C
Kohen
F
F
Pieraccini
G
G
Moneti
G
G
D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry*; D000918:Antibody Specificity; D002417:Cattle; D002853:Chromatography, Liquid; D003101:Collodion; D003429:Cross Reactions / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007118:Immunoassay / Q000295:instrumentation* / Q000662:veterinary; D008297:Male; D013058:Mass Spectrometry; D051379:Mice; D051381:Rats; D012680:Sensitivity and Specificity; D013418:Sulfamethazine / Q000276:immunology / Q000652:urine*; D013552:Swine
D000911:Antibodies, Monoclonal; D013418:Sulfamethazine; D003101:Collodion