Evaluation of gas chromatography with a flame photometric detector based on quartz surface-induced emission for determining the speciation of inorganic and methylgermanium compounds

Gas chromatography-flame photometric detection (GC-FPD) using quartz surface-induced germanium emission allows the sensitive determination of inorganic germanium (Gei) and methylgermanium (MGe) compounds. Grignard pentylation is preferred to other derivative reactions as its products are suitable for the Chromatographic process. Pentylated organogermanium compounds are identified by gas chromatography-mass spectrometry (GC-MS). The typical germanium isotope patterns are obtained on loss of pentyl groups [M-Pe]+ for all four tested compounds. Using the on-column injection technique and a HP-1 capillary column, all four organogermanium compounds are baseline-resolved within 10 min. The absolute detection limits (signals 3 times the standard deviation of baseline noise), for trimethylgermanium (TMGe), dimethylgermanium (DMGe), monomethylgermanium (MMGe) and germanium tetrachloride (TCGe) are 50, 70, 150, and 150 pg, respectively. The response range is linear over 3 orders of magnitude from detection limits up to 50 ng. The analytical figures of merit are compared with those for other techniques in the literature.