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Direct determination of vitamin B 1 in seawater by solid‐phase extraction and high‐performance liquid chromatography quantification
Author(s) -
Okbamichael Mussie,
SañudoWilhelmy Sergio A.
Publication year - 2005
Publication title -
limnology and oceanography: methods
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.898
H-Index - 72
ISSN - 1541-5856
DOI - 10.4319/lom.2005.3.241
Subject(s) - seawater , chromatography , elution , chemistry , extraction (chemistry) , detection limit , solid phase extraction , high performance liquid chromatography , methanol , organic chemistry , oceanography , geology
Vitamin B 1 (thiamine) is one of the organic micronutrients essential for growth of algae. However, there is no direct method for the quantification of this vitamin in natural waters. Bioassay is the only protocol currently available to measure B 1 in the marine environment. We have developed a new method for the direct determination of B 1 , along with vitamin B 12 (cobalamin) in seawater. Solid‐phase extraction with a column of C 18 resin followed by elution with methanol was used to extract dissolved B 1 from seawater. The eluted vitamin was then analyzed by reversed phase high‐performance liquid chromatography (HPLC) using ammonium acetate (0.05 M) and methanol as mobile phases in pressure gradient mode. Ultraviolet‐visible (UV‐Vis) detection at 270 nm was used to quantify B 1 levels. The calibration curve was linear from 0 to 0.60 µM and the detection limit of the protocol was on the order of 0.083 pM. This new method was successfully applied to the determination of vitamin B 1 in filtered coastal seawater, porewater, and river water samples. Concentrations of vitamin B 1 in those aquatic environments ranged from 0.15 nM in river to 0.75 nM in porewaters, with spike recoveries ranging from 93% to 98%.