Direct Mercury Detection in Landfill Leachate Using a Novel AuNP-Biopolymer Carbon Screen-Printed Electrode Sensor

Abstract

A novel Au nanoparticle (AuNP)-biopolymer coated carbon screen-printed electrode (SPE) sensor was developed through the co-electrodeposition of Au and chitosan for mercury (Hg) ion detection. This new sensor showed successful Hg2+ detection in landfill leachate using square wave anodic stripping voltammetry (SWASV) with an optimized condition: a deposition potential of −0.6 V, deposition time of 200 s, amplitude of 25 mV, frequency of 60 Hz, and square wave step voltage of 4 mV. A noticeable peak was observed at +0.58 V associated with the stripping current of the Hg ion. The sensor exhibited a good sensitivity of ~0.09 μA/μg (~0.02 μA/nM) and a linear response over the concentration range of 10 to 100 ppb (50–500 nM). The limit of detection (LOD) was 1.69 ppb, which is significantly lower than the safety limit defined by the United States Environmental Protection Agency (USEPA). The sensor had an excellent selective response to Hg2+ in landfill leachate against other interfering cations (e.g., Zn2+, Pb2+, Cd2+, and Cu2+). Fifteen successive measurements with a stable peak current and a lower relative standard deviation (RSD = 5.1%) were recorded continuously using the AuNP-biopolymer-coated carbon SPE sensor, which showed excellent stability, sensitivity and reproducibility and consistent performance in detecting the Hg2+ ion. It also exhibited a good reliability and performance in measuring heavy metals in landfill leachate.

The present and potential future of aqueous mercury preservation: a review

“…A similar detection limit was reported by Bhardwaj et al (2020) in pond and drain water. 24 Gold nanoparticle electrodes have been developed by Hwang et al (2021) for Hg 2+ determination, achieving detection limits of 1.7 mg L −1 Hg 2+ with a linear response between 10-100 mg L −1 in landll leachates. 25 This highlights the ability for these technologies to be used in difficult matrices, however detection limits are currently unsuitable for speciation analysis or for Hg concentrations found in most natural waters.…”

Recent advances in the modification of electrodes for trace metal analysis: a review

“…NMs have been primarily applied on the electrodes in combination with other modifiers (including through the formation of composites). [22][23][24][25]27,[30][31][32]34,46,47,50,54,59,67,70,72,75,83,85,86,88,89,[92][93][94][95][96][97][98][99][100][101][102]107,113,115,117,118,[122][123][124][125][126][129][130][131]135,136,[138][139]...…”

“…A combination of two polymers (i.e., conductive polydopamine (PDA) doped PPy hydrogel) as modifiers of an SPCE for the determination of Pb 2+ has also been reported. 232 Biopolymers (mainly chitosan and different forms of cellulose) 35,37,61,69,[71][72][73]87,89,92,123,124,175,186,187,197,[200][201][202][203][204][205] (further discussed in section 7) and Nafion (a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer) 24,62,108,113,149,154,155,179,200,[233][234][235][236][237][238][239][240][241] are by far most frequently used as polymeric components of the nanocomposites. Moreover, other conducting polymers such as polyaniline (PANI), 23,38,99,102,122,…”

Sol-Gel Synthesis and Characterization of Highly Selective Poly(N-methyl pyrrole) Stannous(II)Tungstate Nano Composite for Mercury (Hg(II)) Detection

“…Despite these developments in this proposed sensor, there are still a few challenges that need to be addressed before it can be commercialized. A comparison of the electrode parameters of the published study [41][42][43][44][45][46] with the current electrode is given in Table 2.…”