Fe-doped MOF-derived N-rich porous carbon nanoframe for H2 S cataluminescence sensing

Metal-doped porous carbon matrix composites are considered as outstanding H₂ S cataluminescence sensing materials for their good sulfur tolerance and high cataluminescence activity. In this work, Fe-doped MOF-derived N-rich porous carbon nanoframe was successfully fabricated by pyrolysis of Fe-doped ZIF-8 in an Ar atmosphere at a temperature of 900 °C, and used for H₂ S cataluminescence sensing. Along with zinc volatilization, the obtained porous carbon nanoframe not only had high specific surface area and abundant voids, but also had well dispersed Fe species doped in the skeleton. Compared with Fe₂ O₃ /ZnO composites derived from the same precursor but different pyrolysis terms, this as-prepared Fe-doped N-rich porous carbon presented three times increase of cataluminescence intensity towards H₂ S, attributing to the porous carbon skeleton which is indispensable for dispersing catalytic active sites and providing more absorptive surface and voids. Comparably, this proposed sensor demonstrated high sensitivity and good selectivity, with the detection range of 1.57-19.58 μg·mL^-1 and detection limit as 0.13 μg·mL^-1 towards H₂ S. This work may provide a new pathway for preparing catalysts for cataluminescence sensing with better metal distribution, higher specific surface area, richer pores than ever before.

Visual detection of S2- with a paper-based fluorescence sensor coated with CdTe quantum dots via headspace sampling

A simple method was developed in this work for facile and visual detection of S^2- using a paper-based fluorescence (FL) sensor coated with CdTe quantum dots (QDs) by headspace sampling. With the addition of hydrochloric acid, the target S^2- in the liquid phase would transform to H₂ S, which was released to headspace and quenched the FL of CdTe QDs in a linear manner through a gas-solid reaction, with any possible liquid-phase interference avoided. The regular quenching caused by S^2- in analyte solution with increased concentration could be easily observed by the naked eye, and the limit of detection (LOD) for this method was 0.13 μM and 0.93 μM for FL and visual sensing, respectively, comparable or not to that by other sensing probes. A relative standard deviation of 1.2% was accomplished from seven replicated measurements, implying the high reproducibility, and the recovery for the spiked water samples ranging from 94 to 103%, and illustrating the satisfactory reliability of this method. Moreover, the preparation of this paper sensor was facile and did not require any complicated or time-consuming procedures for additional modification or functionalization as for other probes previously reported.

Emerging analytical tools for the detection of the third gasotransmitter H2S, a comprehensive review

BACKGROUND

Hydrogen sulfide (H2S) is currently considered among the endogenously produced gaseous molecules that exert various signaling effects in mammalian species. It is the third physiological gasotransmitter discovered so far after NO and CO. H2S was originally ranked among the toxic gases at elevated levels to humans. Currently, it is well-known that, in the cardiovascular system, H2S exerts several cardioprotective effects including vasodilation, antioxidant regulation, inhibition of inflammation, and activation of anti-apoptosis. With an increasing interest in monitoring H2S, the development of analysis methods should now follow.

AIM OF REVIEW

This review stages special emphasis on the several analytical technologies used for its determination including spectroscopic, chromatographic, and electrochemical methods. Advantages and limitations with regards to the application of each technique are highlighted with special emphasis on its employment for H2S in vivo measurement i.e., biofluids, tissues.

KEY SCIENTIFIC CONCEPTS AND IMPORTANT FINDINGS OF REVIEW

Fluorescence methods applied for H2S measurement offer an attractive non-invasive and promising approach in addition to its selectivity, however they cannot be considered as H2S-specific probes. On the other hand, colorimetric assays are among the most common methods used for in vitro H2S detection, albeit their employment in vivo H2S measurement has not yet been possible . Separation techniques such as gas or liquid chromatography offer higher selectivity compared to direct spectrophotometric or fluorescence methods especially for suitable for endpoint H2S measurements i.e. plasma or tissue samples. Despite all the developed analytical procedures used for H2S determination, the need for highly selective, much work should be devoted to resolve all the pitfalls of the current methods.

Recent advances in cataluminescence-based optical sensing systems

Recent advances in the development of cataluminescence focused on oxygen, temperature, catalyst and instrumentation are summarized.

A sensitive cataluminescence-based sensor using a SrCO3/graphene composite for n-propanol

Adding graphene to SrCO₃ enhanced the CTL intensity of n-propanol, and the SrCO₃/graphene composite was used for sensitive detection of n-propanol.