Environmental Applications of Large Volume Injection in Capillary GC Using PTV Injectors

Significance of the topic

Large volume injection using programmable temperature vaporizing (PTV) injectors streamlines environmental gas chromatographic analyses by replacing labor-intensive solvent evaporation steps with in-injector solvent venting. This approach reduces contamination risk, improves sensitivity, and accommodates “dirty” samples by retaining nonvolatile matrix components in disposable liners.

Objectives and study overview

This study evaluates the performance of large volume PTV injection with packed wide-bore liners for three environmental applications: nitrogen/phosphorus pesticides in river water (GC-NPD), organochlorine pesticides and PCBs in river water (GC-ECD), and polycyclic aromatic hydrocarbons (PAHs) in river sediment (GC-MS). Method optimization, analytical figures of merit, and integration of on-line clean-up are examined.

Methodology and instrumentation

Key methodological elements include

• Packed liners (3.5 mm I.D.) coated with Dexsil-Chromosorb for up to 150 µl injections and fitted with glass frits to secure the packing.
• Stepwise optimization: determination of maximum injectable volume, solvent elimination time via detector monitoring, and splitless transfer conditions.
• Instrumentation: ATI Unicam GC with PTV injector and NPD detector; Perkin Elmer Autosystem GC-MS with PTV injector; ATI Unicam GC with PTV injector and ECD.

Main results and discussion

GC-NPD for polar pesticides

• Sixty-microliter injections yielded higher recoveries and acceptable repeatability (RSD < 10%) versus 1 µl splitless injections.
• Matrix-induced liner deactivation enhanced responses for labile analytes; matrix-matched calibration was necessary for accurate quantification.

GC-MS for PAHs

• Fifty-microliter injections of amino-cartridge eluates enabled identification of over 40 PAHs with sensitivity comparable to conventional evaporative-concentration methods.

GC-ECD for OCPs/PCBs

• Up to 100 µl injections of petroleum ether extracts proceeded without flooding or analyte loss, even for volatile congeners.
• On-line alumina clean-up coupled to PTV injection reduced matrix interferences and achieved low-pg/mL detection limits with satisfactory linearity and precision.

Benefits and practical applications

• Elimination of off-line evaporation accelerates sample throughput and reduces manual handling.
• Disposable packed liners prevent contamination of GC columns and detectors.
• Improved limits of detection scale with injection volume without additional sample cleanup steps.
• Compatibility with various detectors and potential for automation using volume-programmable autosamplers.

Future trends and possibilities

• Advancement of inert packing materials to further protect labile or highly polar analytes.
• Integration of multi-dimensional GC and on-line extraction or cleanup techniques for complex matrices.
• Refinement of pressure and temperature programming to optimize solvent venting and analyte focusing.
• Expansion of large volume PTV approaches to other analytical platforms and emerging contaminant classes.

Conclusion

Large volume PTV injection with packed wide-bore liners offers a robust, sensitive, and efficient strategy for environmental capillary GC analyses. By simplifying sample preparation, improving detection limits, and tolerating complex matrices, it is well suited for routine monitoring of pesticides, PCBs, and PAHs.

References

• Grob K. On-line Coupled LC-GC. Hüthig, Heidelberg, 1991.
• Grob K. Anal. Chem. 66 (1994) 1009A.
• Vreuls JJ, Ghijsen RT, de Jong GJ, Brinkman UATH. J. Chromatogr. 625 (1992) 237.
• Kelly GW, Bartle KD. J. High Resol. Chromatogr. 17 (1994) 390.
• Blomberg J, Schoenmakers PJ, van den Hoed N. J. High Resol. Chromatogr. 17 (1994) 411.
• Louter AJH, Brinkman UATH, Ghijsen RT. J. Microcol. Sep. 5 (1993) 303.
• Goosens EC, de Jong D, de Jong GJ, Rinkema FD, Brinkman UATH. J. High Resol. Chromatogr. 18 (1995) 38.
• Noij THM, van der Kooi MME. Proc. 16th Internat. Symp. Capillary Chromatogr., Riva del Garda, Hüthig, Heidelberg, 1994, p. 1045.
• Morabito PL, McCabe T, Hiller JF, Zakett D. J. High Resol. Chromatogr. 16 (1993) 90.
• van der Hoff GR, Baumann RA, Brinkman UATH, van Zoonen P. J. Chromatogr. 644 (1993) 367.
• Rinkema FD, Louter AJH, Brinkman UATH. J. Chromatogr. 678 (1994) 289.
• Tamilarasan R, Morabito PL, Lamparski L, Hazelwood P, Butt A. J. High Resol. Chromatogr. 17 (1994) 689.
• Venema A, Jelink JT. Proc. 16th Internat. Symp. Capillary Chromatogr., Riva del Garda, Hüthig, Heidelberg, 1994, p. 1035.
• Hinshaw JV. LC-GC Intern. 12 (1994) 526.
• Kubinec R, Kurán P, Ostrovsky I, Soják L. J. Chromatogr. 653 (1993) 363.
• Stottmeister E, Hermenau H, Hendel P, Welsch T, Engewald W. Fres. J. Anal. Chem. 340 (1991) 31.
• Ceulemans M, Lobiński R, Dirkx WMR, Adams FC. Fres. J. Anal. Chem. 347 (1993) 256.
• Linkerhägner M, Stan HJ, Rimkus G. J. High Resol. Chromatogr. 17 (1994) 821.
• Staniewski J, Rijks JA. J. Chromatogr. 623 (1992) 105.
• Staniewski J, Rijks JA. J. High Resol. Chromatogr. 16 (1993) 182.
• Señoráns FJ, Tabera J, Villen J, Herraiz M, Reglero G. J. Chromatogr. 648 (1993) 407.
• Mol HGJ, Janssen H-G, Cramers CA, Brinkman UATH. J. High Resol. Chromatogr. 18 (1995) 19.
• Mol HGJ, Hendriks PJM, Janssen H-G, Cramers CA, Brinkman UATH. J. High Resol. Chromatogr. 18 (1995) 124.
• Wylie PL, Klein KJ, Thompson MQ, Hermann BW. J. High Resol. Chromatogr. 15 (1992) 763.
• Müller HM, Stan HJ. J. High Resol. Chromatogr. 13 (1990) 759.
• Erney DR, Gillespie AM, Gilvydis DM, Poole CF. J. Chromatogr. 638 (1993) 57.
• Rebbert RE, Chesler SN, Guenther FR, Koster BJ, Parris RM, Schantz MM, Wise SA. Fres. J. Anal. Chem. 342 (1992) 30.
• Canton L, Grimalt JO. J. Chromatogr. 607 (1992) 279.