Hydrophilic Indolium Cycloruthenated Complex System for Visual Detection of Bisulfite with a Large Red Shift in Absorption

Abstract

Bisulfite, as an important additive in foodstuffs, is one of the most widely distributed environmental pollutants. The excessive intake of bisulfite may cause asthmatic attacks and allergic reactions. Therefore, the determination and visual detection of bisulfite are very important. Herein, a newly designed hydrophilic indolium cycloruthenated complex, [Ru­(mepbi)­(bpy)2]+ [1; bpy = 2,2′-bipyridine and Hmepbi = 3,3-dimethyl-1-ethyl-2-[4-(pyridin-2-yl)­styryl]­benzo­[e]­indolium iodide (3)], was successfully synthesized and used as a bisulfite probe. The bisulfite underwent a 1,4-addition reaction with complex 1 in PBS buffer (10 mM, pH 7.40), resulting in a dramatic change in absorption spectra with a red shift of over 100 nm and a remarkable change in solution color from yellow to pink. It is worth noting that this obvious bathochromic shift is rarely observed in the detection of bisulfite through an addition reaction. The detection limit was calculated to be as low as 0.12 μM by UV–vis absorption spectroscopy. Moreover, complex 1 was also used to detect bisulfite in sugar samples (granulated and crystal sugar) with good recovery.

A highly sensitive fluorescent probe for the detection of bisulfite ion and its application in living cells

“…This probe is sensitive enough to monitor HSO3comparable to that of other reported HSO3chemosensors [17,38,39,40] ( Table1).…”

“…[38] HSO3 -Fluorescence Citric acid 6.3×10 -6 Ref. [39] HSO3 -Absorbance PBS 3×10 -6 Ref. [40] HSO3 -Fluorescence PBS 3.0×10 -5 This work HSO3 -Fluorescence DMSO-HEPES 8.6×10 -7…”

Responsive ruthenium complex probe for phosphorescence and time-gated luminescence detection of bisulfite

“…Considering the important roles of bisulfite in daily lives and the abundant photophysical and photochemical properties of Ru(II) complexes, this work reports the development of a new responsive Ru(II) complex probe, Ru-azo, for phosphorescence and TGL detection of bisulfite in practical food samples. The idea for designing the probe Ru-azo for bisulfite is based on the following considerations: (1) specific addition reaction between azo group (recognition unit) and bisulfite allows the specific recognition of bisulfite by the probe; 47 (2) unique photophysical properties of Ru(II) complexes ensure the bisulfite detection with high sensitivity; 46,49,50 (3) long-lived emissions of Ru(II) complexes facilitate the TGL detection of bisulfite in autofluorescence-rich samples; 33 and (4) excellent stability and water solubility of Ru(II) complexes enable the phosphorescence and TGL detection of bisulfite in pure water media. 51 On the basis of above considerations, the probe Ru-azo was readily synthesized through a two-step reaction procedure using cis-Ru(bpy)2Cl2 as a starting material (Scheme 2).…”

“…These probes were normally designed based on the HSO3 --triggered recognition reactions, 38 such as nucleophilic addition with ketone or aldehyde groups, [39][40][41][42] glyoxal mono-hydrazone, 43 and other Michael-type additions. [44][45][46][47][48] Nevertheless, there are still some tough issues that need to be addressed for bisulfite detection in practical food samples, especially those with high background autofluorescence signals.…”

Development of a ruthenium(II) complex-based luminescence probe for detection of hydrogen sulfite in food samples

“…In light of the excellent performance of Ru(II) complex-based luminescence probes in the detections of analytes [34][35][36][37], it is anticipated that this luminophore can be modified to be a luminescence probe to contribute to the selective and sensitive detection of hydrogen sulfite in complicated food and biological samples. In the present work, a Ru(II) complex-based luminescence probe bearing aldehyde group modified bipyridine ligands, Ru-CHO, was developed for the recognition and sensing of hydrogen sulfite.…”