Sulfide Species Optical Monitoring by a Miniaturized Silicon Photomultiplier

Abstract

The monitoring of water-soluble pollutants is receiving a growing interest from the scientific community. In this context, sulfide anion species S2− and HS− are particularly relevant since they can cause acute and chronic toxicity including neurological effects and at high concentrations, even death. In this study, a new strategy for fast and sensitive optical detection of sulfide species in water samples is described. The method uses an integrated silicon photomultiplier (SiPM) device coupled with the appropriate analytical strategy applied in a plastic microchip with dried reagents on board. More specifically, all sulfide species (H2S, HS− and S2−) in water samples are detected by the fluorescence signal emitted upon the reaction with N,N-dimethyl-phenylenediamine sulfate in the presence of Fe3+, leading to the formation of the fluorescent methylene blue (MB) species. It has been proven that the system herein proposed is able to measure sulfide concentration in a linear range from 0–10 mg L−1 with a sensitivity value of about 6.7 µA mg−1 L and a detection limit of 0.5 mg L−1. A comparison with conventional UV-Vis detection method has been also carried out. Data show a very good linear correlation (R2 = 0.98093), proving the effectiveness of the method. Results pave the way toward the development of portable and low-cost device systems for water-soluble sulfide pollutants.

Study of a Miniaturizable System for Optical Sensing Application to Human Cells

“…The specific uptake mechanism was not characterized, since there are some studies in the literature [17]. The optical characterization of labeled HDFs by the unconventional photoluminescence system (Figure 2) proved the suitability of our method for the integration in an optical biosensor device; the use of miniaturized photomultipliers, already employed in sensing applications [25][26][27] may result in the fabrication of a portable sensing system that could be used also within incubators. Results from optical testing reported a sensitive Ru(bpy) 3 2+ fluorescence detection, highlighting a strong correlation with both fluorophore concentration and labeling duration.…”

Biosensors in Monitoring Water Quality and Safety: An Example of a Miniaturizable Whole-Cell Based Sensor for Hg2+ Optical Detection in Water

“…The sensor is composed by a cuvette containing a suspension of the E. coli reporter bacteria, and a micro-sized silicon photomultiplier, SiPM, detector, both integrated in a miniaturized dark box. The SiPM is an optical detector widely used in biosensing applications for healthcare and environmental monitoring [54][55][56][57].…”

Silicon Photomultiplier Current and Prospective Applications in Biological and Radiological Photonics

“…Consequently, the challenge associated with collecting these optical signals with sufficient signal-to-noise ratio is enormous. Several studies have shown that using a SiPM as a readout device provides an adequate performance [53,54] combined with the micrometric dimensions that are also required for biosensors [31,55]. Indeed, a recent study revealed that a simple, low cost and portable optical system, with a SiPM optical transducer, is able to detect fluorophore concentrations in the order of 10 -12 M [32].…”