Use of nicotinamide as an internal standard for gas chromatographic quantitation of heroin in illicit forensic drug seizures in Pakistan

Abstract

A precise and economical method using nicotinamide as an internal standard for the quantitation of heroin in illicit forensic drug seizures in Pakistan was developed and validated by gas chromatography coupled with a flame ionisation detector. The retention time of heroin hydrochloride was 6.06 ± 0.2 min using a HP-5 (5% phenyl methyl siloxane) column and 99.9% nitrogen carrier gas. The method showed good linearity (r²= 0.9986) in the range of 0.05–95 mg/ml of heroin hydrochloride. Limits of detection and quantitation were 0.02 mg/ml and 0.05 mg/ml of heroin hydrochloride respectively. Accuracy at three concentrations (20, 50 and 95 mg/ml) ranged from 97–103% and precision ranged from ±1.2–2.5% CV. Forty-five samples seized by the Anti-Narcotics Force of Pakistan were analysed and adulterants were also identified. The proposed method is economic, rapid and involves very little sample preparation, facilitating high throughput that can also be employed for detection of adulterants in heroin seizures.

Keywords:

• heroin
• nicotinamide
• gas chromatography
• flame ionisation detector
• seized samples