Sample vial influences on the accuracy and precision of carbon and oxygen isotope ratio analysis in continuous flow mass spectrometric applications

Due to the small amounts of sample gas involved in continuous flow mass spe ctrometric analysis, care should be taken to evaluate the influence of samp le containers on the carbon and oxygen isotope ratios of samples, Data indi cate that Na-glass and borosilicate glass vials, equipped with butyl rubber septa, can cause significant changes in the isotopic composition of CO2 ga s, even where sample gases are stored within the vial for less than one day . The magnitude of these changes varies from vial to vial. Given the levera ge that contamination can potentially exert on small gas samples, each rese archer should carefully evaluate the effect of sample vials in order to eli minate unknown and unwanted changes in the composition of samples. Copyrigh t (C) 2000 John Wiley & Sons, Ltd.