Large Volume Injection of Pesticides Using Low-Pressure Gas Chromatography

Concurrent Solvent Recondensation Large Sample Volume splitless injection (CSR-LVSI, or LVI) is a gas chromatography sample injection technique that overcomes the limitation of using a smaller sample volume of 1 to 2 µL, which is typical of conventional splitless injections. Low-Pressure Gas Chromatography (LPGC) is a novel technique that has been successfully applied for multiresidue pesticide detection and quantification. The LPGC configuration with the restrictor/guard column facilitates the requirements of a CSR-LVSI and has the potential to improve the sensitivity and lower detection limits. Peak shapes of large-volume injections using both acetonitrile and acetonitrile–toluene were evaluated in the range of 1–25 µL, and the relationship between the peak area and injection volume was established. The large volume injections (>10 µL) resulted in peak splitting when acetonitrile was used. The later eluting peaks were affected more while the effect of increased volume on peak areas for larger than 10 µL injections was negligible. The calibration parameters were compared for 1 and 5 µL injection. The limits of detection and other parameters were comparable between the two injection volumes. This presentation will describe both CSR-LVSI and LPGC and demonstrate the applicability of combining these techniques using a variety of solvents.