HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC DETERMINATION OF ISONIAZID, ACETYLISONIAZID AND HYDRAZINE IN BIOLOGICAL-FLUIDS

The basic principle of derivatization of a hydrazide moiety with an al dehyde as applied in the method developed by Lacroix et al. [J. Chroma togr., 307 (1984) 137-144] for the quantitation of isoniazid and acety lisoniazid was improved by modification, standardization and extension to allow quantitation of hydrazine in patient samples. It could be sh own that 40 mu l of 1% methanolic cinnamaldehyde per 200 mu l of depro teinized analysate gave maximal chromophoric isoniazid-cinnamaldehyde conjugate, read at 340 nm. The hydrolytic loss of isoniazid, crucial t o the quantitation of acetylisoniazid, could be compensated for by int roduction of an appropriate set of calibration curves. Although the me thod described here allows quantitation of monoacetylhydrazine and dia cetylhydrazine, in addition to hydrazine, in mono-spiked samples, the method cannot be used for the quantitation of the acetylated metabolit es of hydrazine in patient samples because of a lack of specificity. L inear calibration curves in the range 1-25 mu g/ml for isoniazid and a cetylisoniazid, 10-400 ng/ml for hydrazine and 50-1000 ng/ml for mono- acetylhydrazine and diacetylhydrazine, could be constructed; analyte r ecoveries approaching 100% could be achieved in all instances.