Spectrofluorimetric determination of surface-bound thiol groups and its application to the analysis of thiol-modified silicas

• Published in: Analyst (London) Vol. 129; no. 9; p. 860
• Main Authors: Howard, A G, Khdary, N H
• Format: Journal Article
• Language: English
• Published: England 01-09-2004
• Subjects: Nanotechnology; Rhodamines - chemistry; Silicon Dioxide - chemistry; Spectrometry, Fluorescence - methods; Sulfhydryl Compounds - analysis; Sulfhydryl Compounds - chemistry
• ISSN: 0003-2654
• DOI: 10.1039/b407566h

A sensitive spectofluorimetric method has been developed for the quantitative measurement of surface-bound thiol groups. The procedure is based on the quantitative esterification of the thiol group with Rhodamine B and its subsequent release from the solid by base hydrolysis for spectrofluorimetric determination. Application of the method to the analysis of thiol-modified nanoparticulate silicas yielded results that compared favourably against alternative approaches based on measurements of mercury capacity and iodometric titration of the thiol groups. Non-specific Rhodamine uptake, assessed using unmodified silica and C18-modified silica, did not significantly influence the analytical results. When applied to a typical 50 mg sample, the detection limit of the procedure was 1 nmole SH g(-1) silica.