Forensics Made Easy

Aug 29, 2017 | Blogs, Forensic | 0 comments

Dr. Michael Pötzsch, Institute of
Forensic Medicine,University of Zurich

Mass spectrometry techniques are now commonplace for high throughput quantitation and screening, but also for research and discovery for food safety, forensics, environmental testing, and a host of other applications. The demands of these settings are different from traditional research, requiring MS systems which combine robust and reliable operation with straightforward day-to-day processing. The SCIEX X500R QTOF System has been developed specifically to meet these needs and is now helping to streamline the workflow of Zurich’s Institute of Forensic Medicine.

Police departments in the Swiss canton of Zurich rely on the Institute of Forensic Medicine, part of the University of Zurich, for screening of biological samples associated with their investigations. The institute’s Department of Forensic Pharmacology and Toxicology uses mass spectrometry to identify and quantify substances which may be relevant to traffic offenses or other crimes, from recreational drugs and alcohol to prescription medicines and poisons, in various challenging biological matrices.

Dr. Michael Pötzsch, a pharmacist in the Department, explained, “We use MS-based methods for most of our routine screening and quantitation activities, including validated quantification of drugs and medications in numerous biological matrices, such as blood. We have been using SCIEX instruments ever since LC-MS applications were first introduced at the institute, and have a number of systems that are used for screening, quantification and research activities, including 3200 QTRAP, QTRAP 4500, QTRAP 5500, QTRAP 6500, and a TripleTOF 6600.”

“We currently perform most of our routine testing on triple quad instruments, with a majority of our FUD (Fahren unter Drogen; driving under the influence of drugs) samples analyzed on an API 3200 QTRAP, quantifying analytes such as cocaine, amphetamine, and morphine. We also quantify a number of other drugs, including benzodiazepines, antidepressants, and neuroleptics, on a QTRAP 5500 System. For research applications, we couple the 4500 QTRAP to an Eksigent MicroLC to achieve the highest sensitivity for special analyses.”

“SCIEX instruments have always been a good choice for our institute, offering robust hardware, reproducible results and the high sensitivity that we need. Our flagship instrument, a TripleTOF 6600, continues this tradition, combining high-resolution mass spectrometry with a high level of sensitivity and speed. The 6600 System is used for some regular testing, particularly when compounds may be present in low concentrations, and is also ideally suited to our research applications, for example, using SWATH Acquisition to investigate the metabolism of new psychoactive substances.

The advantage of SWATH technology is that it allows us to collect as much MS and MS/MS data as possible from a single sample injection. Initially, MS acquisition is performed without collision energy, enabling detection of all the ionized precursors. This is followed by SWATH analysis, subdividing the mass range of interest into predefined mass windows (e.g., 25 Da). These isolated mass windows are then fragmented by collision induced dissociation (CID) to generate MS/MS data. The short cycle time guarantees that enough data points are collected over the chromatographic peak for validated quantitative analysis, offering good accuracy and precision.”

To complement its existing systems and further extend the services it offers, the Institute is currently evaluating the latest SCIEX X500R QTOF System. This robust, high-performance MS system has been developed specifically for routine testing applications in food, environmental and forensics labs, offering exceptional reliability and simple day-to-day operation.”

“The X500R is a very interesting development for routine labs, combining user-friendly software with high-resolution QTOF performance. The new SCIEX operating system, SCIEX OS, offers straightforward method development, acquisition, data handling, and evaluation of the instrument’s mass calibration. Performance is also very simple, just two calibration solutions are required, one negative and one positive, and reports are pre-installed, making life in an accredited environment easier. The easy-to-use app- style software is more straightforward too. Applications such as PeakView™MasterView™ and MultiQuant™ are included as part of a single package, which is less complex than using separate software solutions to run the experiment and analyze the data, and well suited to routine activities.”

“One of the most interesting features of this instrument is its ability to perform acquisitions in a high-resolution multi-reaction monitoring (HR-MRM) mode. This guarantees the highest selectivity, comparable to that of a triple quadrupole instrument. At the moment, we are developing a multi-analyte method capable of processing more than 100 analytes in a single run, which will be a highly beneficial addition to our portfolio. Using a SWATH approach should allow us to screen and quantify additional compounds without influencing the cycle time. We also plan to use the X500R to run several quantitative methods that are currently performed on our triple quad instruments.

Transferring methods from one SCIEX system to another has always been straightforward in our experience, and this will be further simplified for the X500R by a software tool, which allows you to automatically import fragment and collision energy data from existing libraries to generate HR-MRM methods. We have already completed the LC development for the new multi-analyte method on the X500R, and aim to have it fully validated in early 2017. Setting up and running methods on the X500R is generally easier and more open than on triple quad instruments, and this will help to speed up our method development,” Michael concluded.Find out more about the SCIEX X500R QTOF System >

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