Using triple quadrupole GC-MS in Full Scan, SIM, SRM, and mixed scan modes to provide the highest coverage for target and non-target analysis of contaminants
Authors: David Steiniger(1), Dwain Cardona(1), Cristian Cojocariu(2), Paul Silcock(2), Alexander Semyonov(1), Jason Cole(1),
Key words: GC-MS, triple quadrupole, single quadrupole, target, non-target, semi-volatile organic compounds, SVOCs, pesticides
Resumo do Pôster:
4. Results and Discussion
SIM was used for the analysis of tetrahydrocannabinol (THC) in urine samples. THC, THC-OH, and THCCOOH were extracted and derivatized for this study. Concentrations used were the cutoff value (15 ng/mL), 125% of the cutoff value (18.75 ng/mL), and 40% of the cutoff value (6 ng/mL). Table 1 shows the %RSDs of 10 replicate analyses of the three concentrations.
TABLE 1. %RSD of 10 replicates THC samples – Triple Q vs Single Q.
SRM Data: SVOC calibration standards were prepared in methylene chloride from 1 to 1000 ng/mL. Transitions and collision energies for SRM were determined and optimized using the AutoSRM function of the software. Curves using internal standards were generated. The linearity of the curves was >0.99 for all analysed compounds, and the %RSDs for the calibration curve for the triple and single quadrupole were very similar.
SRM/FS Data: A sample of fruit drink was extracted using the QuEChERS method of extraction and cleanup. The extract was concentrated 5 times, and then 147 pesticides were spiked into the extract to produce calibration curves from 1 ng/mL to 200 ng/mL. The calibration curves were constructed for both methods: SRM and alternating SRM/full scan for 147 pesticides. The linearity for most of the compounds was R2 > 0.98 for both methods of analysis. Ten replicates of a 1 ng/mL and 10 ng/mL standard in fruit juice extract were analyzed to determine the MDLs for the two instrument methods. A comparison of the MDLs of both methods show a slightly higher values with the full scan added to the instrument method, but very comparable.