The authors selected 38 thin-layer-chromatography (TLC) systems described in the available literature published over the last 10 years and evaluated those systems with respect to their suitability for detection and identification of opiates in urine, opium and heroin, as well as adulterants in heroin. A total of 14 substances: 8 opiates (morphine, 6-monoacetylmorphine, diacetylmorphine, codeine, acetylcodeine, noscapine, papaverine and thebaine) and 6 adulterants (ephedrine, quinine, methadone, caffeine, cocaine and strychnine) were used as test samples for this research. Using laboratory-coated plates and pre-coated plates, 15 and 13 TLC systems, respectively, were found to be able to detect and identify morphine and codeine in urine without interference from the remaining 12 substances. For the detection of opiates in opium samples as well as opiates and adulterants in illicit heroin samples the TLC system: chloroform-n-hexane-triethylamine (9:9:4) which was developed by the National Drug Research Centre, Penang, Malaysia, was found to be most suitable on both laboratory-coated and pre-coated plates. In addition, the following two systems, one on laboratory-coated plates--hexane-chloroform-diethylamine (50:30:7)--and the other on pre-coated plates--benzene-dioxane-ethanol-ammonia (50:40:5:5; T-7)--were also found to be among most suitable TLC systems for the analysis of opiates in opium samples. The article also presents the relative cost of each of the 38 evaluated TLC systems.
Clandestine heroin laboratories have been a feature of the Malaysian illicit drug scene since soon after the abuse of heroin emerged in 1972. The first few clandestine heroin laboratories which synthesised heroin via the acetylation of imported morphine were uncovered in 1973 and 1977. By the mid-1980s, this type of laboratory was replaced by heroin-cutting laboratories whereby imported high-grade heroin was cut to street heroin. This was to meet the rising demand for the drug owing to the rapid escalation of the number of drug users. Over the years, the most significant change in the composition of the street heroin is the decrease in its purity from 30%-50% to 3%-5%. Caffeine has remained the major adulterant and chloroquine is detected in virtually all recent seizures.
Apart from routine analysis of total morphine content required by the criminal justice system, quantification of other major components in illicit heroin has not been considered by the Malaysian enforcement laboratory. In order to quantify various other cutting agents in addition to alkaloids, a gas chromatographic (GC) method was developed to facilitate simultaneous quantification of eight target analytes commonly found in illicit heroin seized in Malaysia within a 12 min run time. The validation results demonstrated high selectivity with the use of an HP Ultra 2 capillary column. Different solvents were studied and methanol:chloroform (1:9) proved best for sample dissolution. The method was repeatable and reproducible. The study ranges covering 50-150% of the preferred concentrations of the eight analytes obtained r(2)>0.9997. Limits of detection up to 6μg/mL were also obtained and the method achieved 99-102% recovery. The capability of the method in heroin profiling was verified using samples from ten case samples.