R. Harikkhan et Wa. Moats, IDENTIFICATION AND MEASUREMENT OF BETA-LACTAM ANTIBIOTIC RESIDUES IN MILK - INTEGRATION OF SCREENING KITS WITH LIQUID-CHROMATOGRAPHY, Journal of AOAC International, 78(4), 1995, pp. 978-986
A procedure for identifying and quantitating violative beta-lactams in
milk is described, This procedure integrates beta-lactam residue dete
ction kits with the multiresidue automated liquid chromatographic (LC)
cleanup method developed in our laboratory. Spiked milk was deprotein
ized, extracted, and subjected to reversed-phase LC using a gradient p
rogram that concentrated the beta-lactams. Amoxicillin, ampicillin, ce
phapirin, ceftiofur, cloxacillin, and penicillin G were, thus, separat
ed into 5 fractions that were subsequently tested for activity by usin
g 4 kits, beta-lactams in the positive fractions were quantitated by a
nalytical LC methods developed in our laboratory, The LC cleanup metho
d separated beta-lactam antibiotics from each other and from interfere
nces in the matrix and also concentrated the antibiotics, thus increas
ing the sensitivity of the kits to the beta-lactam antibiotics. The pr
ocedure facilitated the task of identifying and measuring the beta-lac
tam antibiotics that may be present in milk samples.