Validation Summaries

Toxicology – QTOF

Multi-drug and Cannabinoids Screen in Blood and Urine by LC/Q-TOF Using SLE+ Extraction Plates

Overview

Idaho State Police Forensic Services (ISPFS) has established methods for the screening and confirmation of over 100 drugs utilizing an SLE+ extraction and running on an LC/MS/MS.   The screening extraction is performed and run on the instrument and after the data is analyzed, the confirmation extraction and run are performed.  These methods work well, and even though we are using different acquisition methods, mobile phases, and columns, best practice is to use two different types of technology for screening and confirmations.  The goal of the Multi-drug and Cannabinoids Screen validations were to develop and assess methods utilizing the LC/Q-TOF that could be used in place of the established screening methods that utilize the LC/MS/MS.

Methods

ISPFS already utilizes proven extraction methods (AM 25, 26, 27, and 28), so these methods were used for the validation with the following modifications:  (1) during the transfer to the SLE plate, 450µl of blood + base mixture or urine + base mixture was transferred and (2) 20% methanol in water (LC/MS grade) was used as the reconstitution solvent.

The following evaluation criteria was used for the methods: (1) the retention time for a peak must be within +/- 0.1minutes of the calibrator and (2) the sample must have a mass accuracy of +/- 10 and/or (3) the sample must have a mass abundance of 40 or greater.  Samples may also be evaluated as positive (typically based on peak presence and shape) or negative (typically based on peak absence or clear indicators that the “peak” is actually background noise) at the analyst’s discretion.  A sample may be moved forward for confirmation with a retention time that is outside the allowable window if it is due to the sample being at a high concentration (which is causing peak widening/shifting).

Results/Conclusions

Limits of detection were established for all compounds that met criteria.  Twenty samples that were previously analyzed were analyzed with the new methods and the results were consistent for seventeen of the twenty samples.  Inconsistencies in the three samples were due to the compound(s) not being included in the scope of the prior testing or not typically being reported (as they were metabolites).

Accuracy, precision and reproducibility, reportable range and sensitivity, specificity and selectivity, ion suppression and enhancement, carryover, interference and robustness, mass identifiers and TOF parameters, and stability were all investigated during the validations and were found to be acceptable for all but three of the compounds in the overall validation.  The three compounds that did not meet the criteria (specifically mass accuracy and/or mass abundance) were not were not included in the final approved method.  There were thirteen compounds that worked in the runs done at the Pocatello laboratory but not in the runs done in the Coeur d’Alene laboratory and as such, the Coeur d’Alene instrument was not approved for use for casework until troubleshooting was done and a performance verification was completed to demonstrate that it was working properly. 

The methods were approved for implementation by the Idaho State Police Forensic Services toxicology section and the analysts that participated in the evaluation were approved to perform the methods.


Filename / LinkSize
Final Validation Summary QTOF Cannabinoids- APPROVED.pdf186.13 Kb
Final Validation Summary QTOF MDS- APPROVED.pdf211.17 Kb
Biology – Fusion System

Executive Summary for Fusion System

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