title: Spectrofluorimetric determination of surface-bound thiol groups and its application to the analysis of thiol-modified silicas.
abstract: 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.
authors.affiliation: School of Chemistry, University of Southampton, Southampton, UKSO17 1BJ.
authors.forename: A G
authors.initials: AG
authors.lastname: Howard
authors.forename: N H
authors.initials: NH
authors.lastname: Khdary
mesh_terms: D036103:Nanotechnology; D012235:Rhodamines / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000379:methods; D013438:Sulfhydryl Compounds / Q000032:analysis* / Q000737:chemistry
chemical_list: D012235:Rhodamines; D013438:Sulfhydryl Compounds; D012822:Silicon Dioxide; C029773:rhodamine B