Randez-Gil F, Daros J A, Salvador A, de la Guardia M
Departamento de Química Analítica, University of Valencia, Burjassot, Spain.
J Pharm Biomed Anal. 1991;9(7):539-45. doi: 10.1016/0731-7085(91)80175-9.
The use of fifth order derivative spectra allows the direct determination of nitrazepam in urine at 388 nm with a limit of detection of 1 microgram ml-1. The determination of nitrazepam in blood plasma can be carried out directly by measurement at 402 nm in the fourth order derivative spectra with a limit of detection of 1.5 micrograms ml-1. Clonazepam can be determined directly in urine samples at 384 nm by using sixth order derivative spectra with a limit of detection of 1 microgram ml-1 and in blood plasma by using fourth order derivative spectra at 384 nm with a limit of detection of 0.5 ppm.
