One-Pot Pretreatment Coupled to Microplasma Optical Emission Spectrometry for Field and Sensitive Determination of Inorganic Mercury and Methylmercury in Fish

Abstract

Field and sensitive analysis of mercury species in seafood is helpful to assess the risk of human exposure to mercury, but the cumbersome pretreatment process is time-consuming and laborious. Herein, a simple one-pot pretreatment system is designed for extraction, separation, and enrichment of inorganic mercury (Hg­(II)) and methylmercury (MeHg) in fish, and coupled to dielectric barrier discharge (DBD) microplasma optical emission spectrometry (OES). Both Hg­(II) and MeHg species in fish can be effectively extracted by tetramethylammonium hydroxide under ultrasound, then separated from the fish matrix by vapor generation and photochemical vapor generation, and finally enriched on the activated carbon electrode tips. Mercury trapped on the activated carbon electrode tips can be rapidly released to produce OES under the DBD microplasma excitation for quantitative analysis. The pretreatment and analysis of a batch of 12 samples are completed within 50 min, and the extraction efficiency of total mercury is up to 90% for 100 mg of freeze-dried fish or 86% for 1 g of fresh fish. Under the optimized conditions, the detection limits are 2 μg kg–1 for Hg­(II) and 1.2 μg kg–1 for MeHg in freeze-dried fish, and precisions are 3.2% for Hg­(II) and 3.9% for MeHg. The present method is applied to the analysis of the certified reference material and real marine fishes, giving rise to spiked recoveries of 95–103%. The present system hardly leads to MeHg and Hg­(II) transforming into each other during extraction, providing a simple, convenient, and low-cost analytical tool to evaluate the risk of mercury species in fish.

Atomic spectrometry update: review of advances in the analysis of clinical and biological materials, foods and beverages

“…For the speciation of Hg in fish, Cai et al devised a “one-pot” system that integrated the extraction, derivatization, separation and enrichment of the Hg prior to determination by OES with a DBD microplasma. 96 The apparatus was able to process 12 samples in parallel, completing the analysis in 50 min. To 100 mg of freeze-dried fish powder or 1 g of minced fresh fish in a quartz reactor (15 mm od, 14 mm id, 65 mm height), 1.5 mL of 25% (m/v) TMAH, 0.5 mL of 0.8% (m/v) SnCl 2 dissolved in 10% (v/v) HCl, and 2 mL of water were added.…”

Development of a droplet cathode glow discharge excitation source for high throughput detection of Li, Ca and K in serum samples

“…Micro-plasma sources have gained signicant attention in the eld of potable and in situ analysis due to their advantages of small size, low cost, and reduced gas/power consumption. [21][22][23][24][25] Several compact and cost-effective instruments based on microplasma excitation sources have been developed, including atmospheric pressure solution cathode glow discharge (ELCAD) 26,27 /solution cathode glow discharge (SCGD), dielectric barrier discharge (DBD), 28,29 atmospheric pressure glow discharge (APGD), 30,31 point discharge (PD) [32][33][34][35] and solution anode glow discharge (SAGD). 36,37 ELCAD/SCGD operate between a metal anode and a owing dynamic cathode glow discharge, allowing the detection of various elements without the need for inert gas like Ar or He.…”

A Portable Microplasma Optical Emission Spectrometric Device with Online Digestion Function for Field and Sensitive Determination of Lead in Biological Samples

“…The optical emission spectrometric (OES) systems based on microplasma excitation sources, including liquid electrode glow discharge (LEGD), atmospheric pressure glow discharge (APGD), , dielectric barrier discharge (DBD), , and point discharge (PD), have the advantages of small size, low power consumption, and low cost, possessing broad application prospects in the field analysis of trace heavy metals. , Among them, PD as an excitation source has the advantages of compact structure and strong excitation ability, which has great potential in the development of portable OES device. However, for field analysis, only sample introduction and detection are often focused on, and sample pretreatment in the field is ignored.…”