Inter-element interfaerences in the determination of arsenic and antimony by hydride generation atomic absorpton spectrometry with a quartz tube atomizer

摘要

The interferencesbetween arsenic and antimony on each other durign the hydride generation atomic absorption spectrometry (HGAAS) determination of arsenic and antimony using a quartz tube atomizer (QTA) wereexamined.in order to eliminate or reduce such intrferences by selective heat decomposition of arsine and stibine,a Pyrex adsorption U-tube trap containing glass wool was placed between the drying tube and the quartz tube atomizer.Although at 250 deg C stibine decomposes and is held almost completely by the trap,arsine is also decomposed to an extent of 24% and,therefore,thermal decompositionis not useful to eliminte antimony interference on arsenic detemrination.The effect of coating the glass wool in the U-tube with antimony on the arsenic suppression of the antimony signal was stdied.The results showed that the antimony coating in the U-tube could not hold arsenic effectively and its interference on the antimony signal could not be eliminated by this means.In the second part of the study,oxygen was supplid to thequartz tube atomizer durign atomizaton in order to study the effect of supplying oxygen on eh antimony signa and on the interference of arsenic in the antimony determination.Sensitivity was increased in the presence of oxygen and interferences of arsenic on antimony determination was decreased by about 10% when oxygen was supplied.It was also observed that the extent of intrferences depended mainly on th einterferent concentration rather than the analyte concentration.