Sensitivity enhancement using a microbore column and pulsed pressure injection in the simultaneous analysis of 356 pesticide multiresidues by gas chromatography–tandem mass spectrometry

For more rapid and sensitive simultaneous analysis of a 356 pesticide multiresidues by gas chromatography–tandem mass spectrometry (GC–MS/MS), a microbore (20 m length × 0.18 mm i.d.) column, instead of the conventional narrow bore column (30 m length × 0.25 mm i.d.), and pulsed pressure injection (PPI) were evaluated in this study. An analysis time of 35.2 min with the narrow bore column was greatly reduced to 17.8 min with the microbore column. Retention times of all target compounds on the new microbore column were adjusted using the automated adjustment of retention time function. The microbore column gave significantly higher peak heights and narrower peak widths compared with the narrow bore column, resulting in enhanced sensitivity. The use of PPI at an optimized pressure of 250 kPa for the microbore column also increased peak heights and signal-to-noise (S/N) ratio by about 30%, indicating more than twofold–threefold enhancement of sensitivity compared with the narrow bore column without PPI. In the best case of the late eluting compound etofenprox, the S/N ratio significantly increased more than ninefold. In conclusion, compared to a narrow bore column, using a microbore analytical column with PPI function produced peak sensitivity enhancement and a shorter analysis time.