An indirect detection strategy-assisted self-cleaning electrochemical platform for in-situ and pretreatment-free detection of endogenous H2S from sulfate-reducing bacteria (SRB)

Abstract

The endogenous hydrogen sulfide (H₂S) can be adopted as an indicator for the indirect detection of sulphate-reducing bacteria (SRB), which considered to be closely related to pipeline corrosion and human intestinal health. Unfortunately, the in-situ detection of endogenous H₂S from SRB in the complex culture medium still faces huge challenges. Besides nonspecific adsorption from the culture medium of SRB, the problem of electrode passivation by produced elemental sulfur during electrochemical detection processes of H₂S cannot be ignored. To address these challenges, herein a synergistic sensing platform based on self-cleaning electrode interface and indirect detection strategy (specific H₂S-induced chemical reaction) is developed. This indirect sensing strategy-assisted self-cleaning electrochemical platform showed a relatively good linear response toward H₂S in the range of 0.5 - 5 μM, and the corresponding limit of detection (LOD) was calculated to be 5.09 nM. More importantly, the satisfactory self-cleaning electrode interface in indirect detection system (with only a 4.10% decrease in signal over 50 electrochemical repeated cycles) showed the electrode surface not being disturbed by elemental sulfur. Furthermore, this good selectivity of the indirect detection strategy in combination with the reproducibility, stability, and antifouling activity of the self-cleaning interface, enabled a synergistic sensing platform to detect H₂S directly in the complex culture medium of SRB without time-consuming sample pretreatments. Moreover, this proposed construction strategy of synergetic sensing platform could be explored to other endogenous molecules in complex environment based on different antifouling materials and specific reactions.

Keywords: Anti-poisoning; Complex samples; In-situ sensing; Synergetic sensing platform.