What is the confirmatory method for measuring drugs of abuse?

The confirmatory method for measuring drugs of abuse is gas chromatography coupled with mass spectrometry (GC-MS). This technique is highly regarded for its accuracy and specificity in identifying and quantifying substances within complex mixtures, such as biological samples.

GC-MS works by first separating the compounds in a sample through gas chromatography, allowing for precise isolation of individual substances. Once separated, mass spectrometry is used to analyze these compounds by measuring the mass-to-charge ratio of their ions. This dual approach provides both qualitative and quantitative data, making GC-MS one of the most reliable methods for confirming the presence of drugs of abuse.

In addition to its high specificity, GC-MS can distinguish between closely related compounds, which is crucial in drug testing since many substances may have similar chemical structures. This level of detail is critical in clinical settings, particularly in forensic and toxicological analysis, where false positives or negatives can have significant implications.

Other methods like high-performance liquid chromatography (HPLC), enzyme-multiplied immunoassay technique (EMIT), and thin layer chromatography (TLC) might be useful for initial screening or qualitative analysis but do not provide the same level of specificity and confirmation that GC-MS offers. HPLC is effective for separating components in a mixture but lacks