[Express determination of beta-lactam antibiotics in biological matter with potentiometric sensors].

Stability of aqueous solutions of beta-lactam antibiotics (sodium benzylpenicillin, oxacillin, amoxycillin, phenoxymethylpenicillin, cefotaxime, cefazolin) in biological matter of various acidity was investigated spectrophotometrically. Potentiometric sensors (based on ionic association of beta-lactam tetradecylammonium) sensitive to penicillins and cephalosporins within the concentrations of 1 x 10(-5) - 1 x 10(-1) M were designed. The sensors provided determination of concentration of individual antibiotics and their summary content in the presence of a significant excess of inorganic ions. Express methods for ionometric determination of beta-lactams in blood serum and mixed saliva were developed.