Enhanced spectrofluorimetric determination of hypochlorite based on the catalytic oxidation of thiamine to thiochrome in the presence of trace ferrocyanide

Abstract

An enhanced spectrofluorimetric method for highly selective and sensitive determination of nmol L À1 of hypochlorite has been performed. In alkaline medium, ferrocyanide was specifically oxidized by hypochlorite to form ferricyanide, which further reacted with nonfluorescent thiamine, resulting in the formation of blue fluorescent thiochrome. Notably, the fluorescence intensities were positively correlated with the concentration of hypochlorite over the range of 0.02-12.5 mmol L À1 . The detection limit was 6.1 nmol L À1 , which was lower than for most of the recently published methods. The experimental conditions were optimized and effects of coexisting substances were evaluated and the results showed excellent priority since a certain amount of other anions, including ClO 3 À , BrO 3 À , IO 3 À , Cr 2 O 7 2À and other acid radicals, would not interfere with the measurement.

Thiamine Assays—Advances, Challenges, and Caveats

“…Although not assays for the thiamine molecule, thiamine has been recently used as a probe itself for assaying other analytes. Examples include the detection of prion proteins, uric acid, hypochlorite, and thiaminase activity . It has been used as a fluorimetric substrate in conjunction with co‐immobilized uricase and horseradish peroxidase in an assay for uric acid and, in an assay for hypochlorite, alkaline ferrocyanide could be reduced by the analyte to ferricyanide, which could serve to oxidize thiamine .…”

“…Examples include the detection of prion proteins, uric acid, hypochlorite, and thiaminase activity . It has been used as a fluorimetric substrate in conjunction with co‐immobilized uricase and horseradish peroxidase in an assay for uric acid and, in an assay for hypochlorite, alkaline ferrocyanide could be reduced by the analyte to ferricyanide, which could serve to oxidize thiamine . Thiamine radiolabeled on its thiazole ring with 13 C is also used in an assay for thiaminase activity in biological samples .…”

A selective fluorescence quenching method for the determination of trace hypochlorite in water samples with nile blue A

“…As well known, owing to their high sensitivity and selectivity, fluorescence techniques have been widely used for rapid determination of various analytes [6]. Recently, some recent probes have been developed for hypochlorite based on its strong oxidation properties [7][8][9][10][11][12][13][14][15][16][17]. For example, dibenzoylhydrozine to dibenzoyl diimide [7], oxidation reactions of thiol to sulfonate derivative [8], p-methoxyphenol to benzoquinone [9], hydrazone to aldehyde [18], and oxidation of * Corresponding author.…”

Stability-Indicating Photochemical Method for the Assay of Thiamine by Spectrophotometry

“…It is extensively used as a component of single vitamin B complex and multivitamin preparations [2][3][4]. Several analytical methods, including UV and visible spectrophotometric and multivariate analysis [5][6][7], fluorimetric [8][9][10][11][12][13][14][15][16][17][18][19][20][21], high performance liquid chromatography (HPLC) [22][23][24][25][26][27][28][29][30][31][32][33][34][35], UHPLC/MS-MS [36], turbidimetric and nephelometric [37], amperometric [38], and voltammetric methods [39][40][41][42][43][44][45], have been used for the assay of thiamine and its salts in pharmaceutical preparations, food materials and biological fluids. Some of these methods have previously been reviewed [46][47][48]…”

“…iamine undergoes chemical [1,8,9,11,14,16,17,19,[51][52][53][54] and photochemical oxidation [55,56] to form thiochrome (TC) which exhibits a blue fluorescence (440 nm). is has been made as the basis of fluorimetric determination of TH [8,9,11,14,16,17,19,[54][55][56][57][58][59][60].…”