Spectrofluorometric assay of gentamicin in serum

A spectrofluorometric method has been developed for the assay of gentamicin in serum. The fluorogen of this reaction is the Zn2+ chelate of N-pyridoxylidene gentamicin. The ratio of gentamicin to Zin is 1.0. Interfering compounds in serum are removed by chromatography on Bio-Rex 70. Recovery of added gentamicin is between 90 and 100%. Determination of gentamicin levels in patient sera correlate well with those done by bioassay. This assay is relatively fast (about 1 h), and requires 1.0 ml of serum. It also can be applied to the determination of other deoxystreptamine antibiotics such as kanamycin and tobramycin.