Quantitation of pentobarbital in serum by enzyme immunoassay

Pentobarbital was quantitated in serum by a homogeneous enzyme immunoassay (EMIT), and the method evaluated for accuracy and precision. A comparison was performed against the authors' modified Goldbaum ultraviolet spectrophotometric procedure. The analytical sensitivity was 2 micrograms/mL with a linearity to 10 micrograms/mL and a coefficient of variation of 6.24%. Linear regression analysis revealed a correlation coefficient of 0.977, a slope of 1.05, and an intercept of -0.07. The t test demonstrated no difference between the two methods at a level of P less than 0.01. The enzyme immunoassay also had the advantages of speed and small sample requirement.