Introduction
Methamphetamine (MA) is a dangerous drug that has serious effects on public health due to its widespread abuse. It's classified as a type of stimulant and is the second most commonly abused illicit drug after cannabis. In Sri Lanka, it's known by various street names like meth or ice and can cause heightened alertness, euphoria, and increased energy levels. However, chronic use can lead to severe neurological problems, including cognitive impairment and psychosis. Sri Lanka, like many other countries, faces issues related to drug abuse and trafficking. Situated between major poppy-growing areas, it has become a transit point for illegal drugs, impacting the country's socio-economic policies and safety.
Objective and Methodology
The main goal of this study is to develop and validate a technique using Gas Chromatography with Flame Ionization Detector (GC-FID) to determine the purity of methamphetamine in samples obtained from the police. We analyzed forty samples collected between 2019 and 2021 from the narcotics section of the Government Analyst's Department. These samples underwent various qualitative tests such as the Marquis test, Simon’s test, TLC, GC-MS, and FTIR. For quantitative analysis, we used GC-FID.
Results
All samples tested positive for the presence of methamphetamine through the presumptive tests, TLC, GC-MS, and FTIR. We experimented with different parameters of GC-FID based on boiling points, including temperature programs, flow rates, and split ratios. After investigation, we selected the optimal parameters for good resolution. The developed method was then validated for linearity, precision, limit of detection (LOD), and limit of quantification (LOQ). Calibration curves were constructed by plotting peak area ratios against MA concentrations in the ranges of 10-50 mg/L and 50-400 mg/L. The correlation coefficient values for linearity were 0.9985 and 0.9978, respectively. Precision, evaluated using the relative standard deviation (RSD) for a set of replicate data, was found to be less than 2%. The LOD and LOQ were determined to be 5.32 mg/L and 5.98 mg/L, respectively.
Conclusion
The developed and validated method successfully determined the purity of methamphetamine in test samples. This method can aid in addressing drug-related issues in Sri Lanka by providing accurate and reliable analysis of illicit drug samples.