HR: 08:45h
AN: B51F-04    [Abstracts]
TI: Selective Characterization of Phosphorus Oxyanions in Synthetic Geothermal Water Using IC/MS Methods
AU: * Foster, K L
EM: kfoster@calstatela.edu
AF: Dept. of Chem. and Biochem., California State University, Los Angeles 5151 State University Drive, Los Angeles, CA 90032-8202 United States
AU: * Foster, K L
EM: kfoster@calstatela.edu
AF: CEA-CREST Program, California State University, Los Angeles 5151 State University Drive, Los Angeles, CA 90032-8201 United States
AU: Ivey, M M
EM: michelle$\_$ivey@HMC.edu
AF: Dept. of Chem. and Biochem., California State University, Los Angeles 5151 State University Drive, Los Angeles, CA 90032-8202 United States
AU: Ivey, M M
EM: michelle$\_$ivey@HMC.edu
AF: CEA-CREST Program, California State University, Los Angeles 5151 State University Drive, Los Angeles, CA 90032-8201 United States
AB: Recent studies show microorganisms contain enzymes used to metabolize reduced trivalent (III) phosphite and univalent (I) hypophosphite, suggesting that microorganisms can utilize phosphorus oyxanions in oxidation states other than pentavalent (V) phosphate, the most common form of bioavailable phosphorus. Moreover, highly reduced forms of phosphorus, namely phophine (-III) have been detected in nature in reducing environments such as sewage, marine sediments, and in industrial and agricultural processes. The combination of these studies has made it increasingly important to develop sensitive and selective biogeochemical methods that distinguish between the different oxidation states of filterable inorganic phosphorus oxyanions in natural water. Our laboratory has developed ion chromatography methods that use conductivity detection to separate hypophosphite, phosphite and phosphate in a synthetic geothermal water matrix, however, resolution challenges limit the sensitivity of this technique. This paper will discuss a new 2-D technique that couples ion chromatography with electrospray mass spectrometry (IC/MS) with limits of detection up to 45 times lower than those reported in previous studies. The technique was optimized for the detection hypophosphite, phosphite, and phosphate in a synthetic geothermal water matrix consisting of fluoride, chloride, bromide, nitrate, bicarbonate, and sulfate. Samples were pretreated with Dionex OnGuard II silver and hydrogen cartridges to remove excess chloride, bromide and bicarbonate anions that reduced the instrument sensitivity for the phosphorus oxyanions. Injection loop sizes as large as 900 $\mu$L were employed to further improve instrument sensitivity. The estimated 3$\sigma$ limits of detection are 0.047 $\mu$M, 0.0086 $\mu$M, and 0.12 $\mu$M for hypophosphite, phosphite, and phosphate, respectively. The implications of these results to the biogeochemistry community will be discussed.
DE: 1800 HYDROLOGY
DE: 0330 Geochemical cycles
DE: 0394 Instruments and techniques
DE: 0400 Biogeosciences
DE: 1000 GEOCHEMISTRY (New field, replaces Rock Chemistry)
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting