GC/MS/MS Forensic Toxicology Database
The dedicated launcher displayed on-screen helps navigate the necessary operations. Therefore, even first-time users can analyze samples easily by simply following the instructions on the launcher. During autotuning or when measuring performance check (negative control) samples, the software automatically uses a performance check function to check the status of the MS, consumable use time, and columns in order to evaluate the overall status of the system.
For toxicological analysis of whole blood samples, the extraction and purification processes have been optimized using the QuEChERS method. Preparing samples is simplified by using the Sample Preparation navigator to display photographs with instructions for each step of the QuEChERS cleanup process.
To improve the accuracy of semi-quantitation without a standard, the internal standard that is selected and the recovery rate of sample preparation need to be considered.
For internal standards, the Quick-DB Forensic database uses six types of deuterium-labeled toxicological substances that exhibit the same behavior as registered compounds. By using the calibration curve information from a whole blood sample spiked with a standard and pretreated, the quantitative error due to matrix interference, recovery rates of sample preparation, and other factors, which can have a significant effect on quantitative accuracy, can be reduced and accurate semi-quantitation values can be obtained without using a standard.
Using a Deuterium-Labeled Internal Standard to Correct for Sensitivity Variations
Deuterium-labeled internal standards can also be used to correct for GC-MS/MS sensitivity variations, even if the variations cause the response to target compounds in calibration curves to be different than in a customer's instrument.
Using a Calibration Curve for a Pretreated Sample to Correct for Recovery Rates
By using the calibration curve information from a pretreated sample, accurate quantitative values can be obtained. The calibration curve information is used to correct for differences in recovery rates for each target compound or correct for effects caused by adsorption, which occurs when creating calibration curves using standards.
If a high concentration of a target compound is detected in a test sample, carryover within the system may cause doubt about a false positive in the next test sample. If that occurs, the test sample is normally measured again to confirm the results. This may be an impossible task if only small quantity of sample is available and pretreatment must be done.
Therefore, the Quick-DB Forensic database includes a Smart Scheduling function. This function automatically measures a solvent blank if the concentration of a target compound measured in a test sample is higher than a specified value. Smart Scheduling can prevent the risk of carryover causing a false positive.