Advanced TOF-MS technology enables fast, sensitive, and reliable detection of drugs of abuse in urine.

Urine testing is one of the most common screening methods to detect the use of drugs of abuse (DOA) within 72 hours of that use. Gas chromatography-mass spectrometry (GC-MS) has traditionally been used for this type of analysis, but the efficiency of this method can be jeopardized by the high matrix effects and frequent coelution that occur as a result of the chemical complexity of urine.The technique also exhibits limited sensitivity in the analysis of certain drugs while being associated with false positive results. Newly introduced time-of-flight mass spectrometry (TOF-MS) technology offers high sensitivity and superior spectral quality, allowing for increased confidence in results.

This article describes an experiment whereby DOA were extracted from a urine sample and fast GC was performed with detection using the novel TOF-MS technique. Additionally, deconvolution and data-mining software was applied to the TOFMS data. Using this software, a target library of drugs of interest was created and data were processed to automatically identify target compounds within the urine sample.

Background
The analysis of urine for DOA can be used to evaluate possible accidental or intentional overdose or poisoning, to assess the type and amount of prescribed and/or illicit drugs used by a person, or to determine the cause of acute drug toxicity. It is also used to monitor drug dependency or to determine the presence of drugs in the body for medical and legal purposes. Urine drug screening allows for the detection of drugs such as marijuana, cocaine, heroin, and amphetamines as well as their metabolites. In many occupations, urine drug screening has become a required condition of employment.

Urine is a sample that exhibits high chemical complexity, resulting in increased matrix effects and coelution.As a consequence, the analysis of urine is a particularly challenging task, especially when trying to identify trace levels of DOA. Obtaining fast, sensitive, and reliable results from urine analysis is of utmost importance for forensic laboratories. A powerful method is required that is capable of eliminating matrix effects and coelution, as well as facilitating accurate and dependable identification of trace levels of DOA.

GC-MS has been extensively used for this type of analysis, however historical techniques require derivatization to allow the detection of polar compounds. It has also been demonstrated that some GC-MS methods often fail to detect morphine and benzoylecgonine at concentrations above 1.3mg/l and 0.5mg/l respectively. Additionally, there have been cases of false positive results reported due to similar retention times and mass spectra of different compounds.

The forensic industry has been increasingly turning to modern time-of-flight (TOF)-MS instruments as a viable solution for precise screening of urine samples for DOA. These high sensitivity instruments may be used in combination with data-mining and deconvolution software to eliminate matrix effects and co-elution.