Speciation of four selenium compounds using high performance liquid chromatography with on-line detection by inductively coupled plasma mass spectrometry or flame atomic absorption spectrometry |
| |
Authors: | G Alsing Pedersen and E H Larsen |
| |
Institution: | (1) National Food Agency of Denmark, Institute of Food Chemistry and Nutrition, M?rkh?j Bygade 19, DK-2860 S?borg, Denmark, DK |
| |
Abstract: | An analytical method for the speciation of selenomethionine, selenocystine, selenite and selenate by high performance liquid
chromatography (HPLC) with atomic spectrometric detection is presented. An organic polymeric strong anion exchange column
was used as the stationary phase in combination with an aqueous solution of 6 mmol L–1 of salicylate ion at pH 8.5 as the mobile phase which allowed the isocratic separation of the four selenium analytes within
8 minutes. The separated selenium species were detected on-line by flame atomic absorption spectrometry (FAAS) or inductively
coupled plasma mass spectrometry (ICP-MS). The signal-to-noise ratio of the FAAS detector was optimized using a hydrogen-argon
entrained-air flame and a slotted-tube atom trap (STAT) in the flame. The limit of detection (3 σ) achieved by the HPLC-FAAS
system was 1 mg L–1 of selenium (100 μL injections) for each of the four selenium species. More powerful selenium detection was achieved using
an ELAN 5000 ICP-MS instrument. Selenium was measured at m/z = 82. The ICP-MS signal intensity was enhanced by a factor of
3–4 after addition of 3% methanol to the chromatographic mobile phase and by using an increased plasma power input of 1300
W. The limit of detection achieved under these conditions was 1 μg L–1 (100 μL injections). The HPLC-ICP-MS system was used for selenium speciation of selenite and selenate in aqueous solutions
during a BCR certification exercise and for selenium speciation in the certified reference material, BCR No. 402 White Clover.
Extraction experiments revealed that the selenium species in the biological material were extractable only in the presence
of water in the extraction medium. The results indicated that selenate and a compound of unknown identity U were present in
the plant sample.
Received: 4 September 1996 / Accepted: 12 December 1996 |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|