PMID- 25707674
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20150515
LR  - 20150318
IS  - 1520-6882 (Electronic)
IS  - 0003-2700 (Linking)
VI  - 87
IP  - 6
DP  - 2015 Mar 17
TI  - Ion-pair chromatography coupled to inductively coupled plasma-mass spectrometry
      (IPC-ICP-MS) as a method for thiomolybdate speciation in natural waters.
PG  - 3388-95
LID - 10.1021/ac5046406 [doi]
AB  - Molybdenum precipitates preferentially under reducing conditions; therefore, its 
      occurrence in sediment records is used as an indicator of paleoredox conditions. 
      Although thiomolybdates (MoO4-xSx(2-) with x = 1-4) supposedly are necessary
      intermediates in the process of molybdenum precipitation under anoxic conditions,
      there is no information about their abundance in natural environments, because of
      a lack of element-specific methods with sufficiently low detection limits. Here, 
      we optimized ion-pair chromatographic separation for coupling to an inductively
      coupled plasma-mass spectrometry detector (IPC-ICP-MS). 2-Propanol (10%-25%
      gradient) replaced the previously used acetonitrile (25%-75%) as the solvent, to 
      reduce the carbon load into the plasma. In synthetic solutions, formation of
      thiomolybdates was found to occur spontaneously in the presence of excess sulfide
      and the degree of thiolation was highest at pH 7. Excess hydroxyl led to a
      transformation of thiomolybdates to molybdate. Under acidic to neutral
      conditions, precipitation of molybdenum and hydrolysis of tetrathiomolybdate were
      observed. Flash-freezing was found to be suitable to stabilize
      tetrathiomolybdate, with <4% transformation over more than two months. High ionic
      strengths matrices (>2 mM) negatively affected the detection of molybdate, which 
      eluted mainly in the dead volume, but had no negative effect on higher thiolated 
      molybdates. Detection limits were approximately 10 nM. With the newly developed
      IPC-ICP-MS method, thiomolybdates were found to form spontaneously in euxinic
      marine waters after adding a molybdate spike and occur naturally in sulfidic
      geothermal waters.
FAU - Lohmayer, Regina
AU  - Lohmayer R
AD  - daggerDepartment of Environmental Geochemistry, Bayreuth Center for Ecology and
      Environmental Research (BayCEER), University of Bayreuth, Universitaetsstrasse
      30, 95440 Bayreuth, Germany.
FAU - Reithmaier, Gloria Maria Susanne
AU  - Reithmaier GM
AD  - daggerDepartment of Environmental Geochemistry, Bayreuth Center for Ecology and
      Environmental Research (BayCEER), University of Bayreuth, Universitaetsstrasse
      30, 95440 Bayreuth, Germany.
FAU - Bura-Nakic, Elvira
AU  - Bura-Nakic E
AD  - double daggerCenter for Marine and Environmental Research, Ruder Boskovic
      Institute, Bijenicka 54, 10000 Zagreb, Croatia.
FAU - Planer-Friedrich, Britta
AU  - Planer-Friedrich B
AD  - daggerDepartment of Environmental Geochemistry, Bayreuth Center for Ecology and
      Environmental Research (BayCEER), University of Bayreuth, Universitaetsstrasse
      30, 95440 Bayreuth, Germany.
LA  - eng
PT  - Journal Article
DEP - 20150302
PL  - United States
TA  - Anal Chem
JT  - Analytical chemistry
JID - 0370536
EDAT- 2015/02/25 06:00
MHDA- 2015/02/25 06:01
CRDT- 2015/02/25 06:00
PHST- 2015/02/25 06:00 [entrez]
PHST- 2015/02/25 06:00 [pubmed]
PHST- 2015/02/25 06:01 [medline]
AID - 10.1021/ac5046406 [doi]
PST - ppublish
SO  - Anal Chem. 2015 Mar 17;87(6):3388-95. doi: 10.1021/ac5046406. Epub 2015 Mar 2.