Fluorometric determination of sulfide ions via its inhibitory effect on the oxidation of thiamine by Cu(II) ions

Abstract

A fluorometric assay is described for sulfide ions determination. It is based on the finding that the oxidation of the non-fluorescent substrate thiamine (TH) by Cu(II) in basic solution to form fluorescent thiochrome is inhibited by sulfide ions. This results in a decrease in fluorescence intensity which is proportional to the concentration of sulfide ions. Under the optimized conditions, the decrease in fluorescence, best measured at excitation/emission wavelengths of 370/440 nm, decreases linearly in the 0.03 to 2.5 μM sulfide ions concentration range. The detection limit is 20 nM. The method shows excellent selectivity over many potentially interfering ions and has been successfully applied to the determination of sulfide ions in spiked tap water, lake water and the synthetic wastewater samples. The method is time-saving and environmentally friendly, and in our perception shows a great potential in water quality inspection and environmental monitoring. Graphical abstract A fluorescent assay for sulfide ions detection is proposed based on its inhibitory effect on the oxidation of thiamine by Cu(II) ions.

Dye‐linked Upconverting Nanophosphor‐based Ratiometric Chemosensor for NIR‐excited and FRET‐mediated Ultrasensitive Detection of Sulfide Ions

“…[1][2][3] Excess sulphide ions in industrial effluent have a negative impact on water quality and pose a health risk to living organisms. [4][5][6] S 2À ions are oxygenconsuming compounds in water that lower the concentration of dissolved oxygen in the water and hinder aquatic life activity. [7] Human health can be compromised by the exposure to S 2À even at low concentration, which can result in several clinical problems such as dizziness, nausea, vomiting, and headaches.…”

“…Aside from these industrial operations, it is also generated by anaerobic bacteria reducing sulphate or sulfur‐containing amino acids in the meat industry [1–3] . Excess sulphide ions in industrial effluent have a negative impact on water quality and pose a health risk to living organisms [4–6] . S 2− ions are oxygen‐consuming compounds in water that lower the concentration of dissolved oxygen in the water and hinder aquatic life activity [7] .…”

Sensitive Fluorescence Assay for the Detection of Alkaline Phosphatase Based on a Cu2+-Thiamine System

“…Thiamine (TH), also known as vitamin B1, has been utilized as a non-fluorescent substrate [26][27][28]. It has attracted tremendous attention for its low cost, good water-solubility, and easy accessibility.…”