A ceramic microchip with LDA-APGD as the excitation source for OES-a sensitive Hg detecting sensor for microsample analysis

A novel portable excitation microsource for optical emission spectrometry (OES) based on atmospheric pressure glow discharge with a liquid drop anode (LDA-APGD), generated in a ceramic microchip (mch), was developed. This excitation microsource uses low temperature cofired ceramic (LTCC) microchips to provide electrical contact and fabricate a hollow to hold a microsample solution. Optimization of this new excitation source was performed for the quantification of Hg in liquid samples and discussed. Optimal parameters for Hg determination were: polarized liquid drop-anode, discharge current-80 mA, solution drop volume-15 μL, He flow rate-300 mL min-1, chip hollow dimensions: diameter 3.0 mm and depth 0.6 mm, HNO3 concentration-0.10 mol L-1. The addition of low molecular weight organic compounds (LMWOCs) to the solution was also tested. The linearity range for mch-LDA-APGD was up to 30 mg L-1, and the limit of detection (LOD) of Hg was 47 μg L-1. Precision of this method was within 0.65-8.7% (as the relative standard deviation of repeated measurements). Recoveries obtained for tap water samples spiked with Hg(ii) ions at 100, 200, and 300 μg L-1 were within the range of 96-122%.