Current status of non-targeted liquid chromatography-tandem mass spectrometry in forensic toxicology

A core task of any forensic toxicology lab is providing comprehensive information on the chemical composition of evidence. This mission can only be accomplished by combining efficient detection techniques with reliable identification procedures. A competent approach for the sensitive detection of a large variety of potentially toxic compounds is liquid chromatography/tandem mass spectrometry (LC/MS/MS). The concept of non-targeted analysis is realized by applying either data-dependent or data-independent acquisition strategies. Non-targeted LC/MS/MS produces informative features for subsequent compound identification. Of particular importance is the availability of fragmentation information. Additionally, retention times and isotopic distributions may be used. During the identification process, extracted features are matched against data sets obtained from reference standards. Reference data is often stored in databases. State-of-the-art tandem mass spectral databases enable automated compound identification with high sensitivity and specificity. Nevertheless, the final decision on identity is still taken by an expert who carefully reviews the provided arguments.