Spectrophotometric determination of sulfhydryl concentration on the surface of thiol-modified chromatographic silica particles using 2,2′-dipyridyl disulfide reagent

• Published in: Analytica chimica acta Vol. 533; no. 2; pp. 179 - 183
• Main Authors: Nogueira, R., Lämmerhofer, M., Maier, N.M., Lindner, W.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 28-03-2005; Elsevier
• Subjects: 2,2′-Dipyridyl disulfide; Analytical chemistry; Chemistry; Chromatographic methods and physical methods associated with chromatography; Chromatographic particles; Exact sciences and technology; Functionalized silica; High performance liquid chromatography; Other chromatographic methods; Spectrometric and optical methods; Spectrophotometric; Thiol; Thiol-disulfide exchange reaction; 2,2′-Dipyridyl disulfide; Functionalized silica; Thiol; Chromatographic particles; Thiol-disulfide exchange reaction; Spectrophotometric; High performance liquid chromatography; Elementary analysis; HPLC chromatography; 2,2'-Dipyridyl disulfide; Ultraviolet spectrometry; Repeatability; Organic disulfide; Chemical modification; Linearity; Sulfhydryl radicals; Silica gel; Control method; Sulfur; Quantitative analysis
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2004.11.017

This article describes a straightforward method for the quantification of thiol groups on the surface of chromatographic particles such as 3-mercaptopropyl silica gel. The method is based on a thiol-disulfide exchange reaction with 2,2′-dipyridyl disulfide (DPDS) reagent and spectrophotometric or HPLC-UV determination of the liberated 2-pyridyl thione. Linearity was obtained over the sulfhydryl concentration range of 0.02–0.5
μmol
ml
−1 for the spectrophotometric determination and 0.2–5
μmol
ml
−1 for the HPLC-UV measurement, with
r
2 values of 0.9975 and 0.9981, respectively. The results were validated using elemental analysis as independent control method. The agreement between the results of both methods indicates that the sulfur of the thiol-modified silica particles is available as reactive sulfhydryls. The repeatability study indicated a higher precision for the DPDS method compared to the elemental analysis.