Determination of a quaternary mixture of vitamins B6, B1, and B12 and uridine 5'-triphosphate, by derivative spectrophotometry.

A new method for determining a quaternary mixture of vitamins B6, B1, and B12 and uridine 5'-triphosphate (UPT) using second-derivative spectrophotometry is described. Calibration graphs were linear up to 30 micrograms/mL of vitamin B6 at 307 nm (r = 0.9999) and vitamin B1 at 282.7 nm (r = 0.9997) and up to 35 micrograms/mL of vitamin B12 at 360.5-374 nm, peak-to-peak (r = 0.9999), and UTP at 261 nm (r = 1.0000). Detection limits at the p = 0.05 level of significance were calculated to be 0.20, 0.46, 0.22, and 0.20 microgram/mL for vitamins B6, B1, and B12 and UTP, respectively. An exhaustive statistical analysis of the experimental data was performed to confirm the validity of the method. The procedure does not require any separation step or solving of equations. The method was successfully applied for determining synthetic mixtures and commercial injections for these drugs.