1. Polarographic and liquid chromatographic methods for the determination of sulfur residues on grapes and wheat
- Author
-
Jaap Struijs, Huub H. van den Broek, and Goewie Ce
- Subjects
Detection limit ,chemistry.chemical_classification ,Polarography ,Chromatography ,Sulfide ,chemistry.chemical_element ,Dropping mercury electrode ,Biochemistry ,Sulfur ,Amperometry ,Analytical Chemistry ,chemistry.chemical_compound ,chemistry ,Environmental Chemistry ,Methanol ,Ammonium acetate ,Spectroscopy - Abstract
Sampled d.c. and differential pulse polarography are used, in batch mode, to determine sulfur in methanol/0.1 M ammonium acetate (pH 5.0). A two-electron reaction (reduction of sulfur to sulfide) is shown to be involved. Differential pulse polarography is sensitive for the determination of sulfur in relatively clean solutions; the detection limit is 7.2 μg l−1. The interference of heavy metals (Pb and Cd) is avoided by addition of EDTA. For complex matrices, such as extracts of wheat and grapes, matrix effects are serious. For such samples, reversed-phase liquid chromatography with amperometric detection (dropping mercury electrode) gives excellent results. A relatively simple procedure is described for the determination of sulfur residues in wheat and grapes at levels ⩾ 0.5 mg kg −1; linear response is obtained up to ca. 7 mg kg−1.
- Published
- 1988
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