This work presents a simple and innovative protocol employing a microfluidic paper-based analytical device (µPAD) for equipment-free determination of mercury. In this method, mercury (II) forms an ionic-association complex of tetraiodomercurate (II) ion (HgI42−(aq)) using a known excess amount of iodide. The residual iodide flows by capillary action into a second region of the paper where it is converted to iodine by pre-deposited iodate to liberate I2(g) under acidic condition. Iodine vapor diffuses across the spacer region of the µPAD to form a purple colored of tri-iodide starch complex in a detection zone located in a separate layer of the µPAD. The digital image of the complex is analyzed using ImageJ software. The method has a linear calibration range of 50–350 mg L−1 Hg with the detection limit of 20 mg L−1. The method was successfully applied to the determination of mercury in contaminated soil and water samples which the results agreed well with the ICP-MS method. Three soil samples were highly contaminated with mercury above the acceptable WHO limits (0.05 mg kg−1). To the best of our knowledge, this is the first colorimetric µPAD method that is applicable for soil samples including mercury contaminated soils from gold mining areas.
Cardiovascular disease still one of the highest death factor in Indonesia. Ginger as an anti-atherosclerosis could be one of the alternatives that is being developed to decrease the cardiovascular disease. The general aims of this research were determining the mechanism of ginger as anti-atherosclerosis to decrease the risk of cardiovascular disease. Research design used was “The Randomized Posttest only Control Group Design”. In this research, the experimental unit was Rattus norvegicus, male; in the age of 3 months and total number were thirty. Independent variable of this research was steeping of ginger, the dose various of steeping ginger (control, 1g, 3g, 3g + bay leaf, and 5g), and dependent variable was Tumor Necrotic Factor (TNF)α of tissue lipid. TNF α expression was measured by using ELISA method. The data was analyzed by using ANOVA. Based on the analysis, it showed that steeping of ginger was decreased the expression of TNF-α in fat tissue (1g = 551 pg/mL, 3g = 511 pg/mL, 3g + bay leaf = 493 pg /mL) compare to control (986.8 pg/mL) but on the 5 g dose there is contradictory effect that is there is increasing TNF α (1103.5 pg/mL). Conclusion, steeping of ginger potentially decrease the risk of atherosclerosis by attenuate of TNF α expression.
A new spectrophotometric method for mercury determination has been developed based on the complexation of mercury(II) in ascertained excess of thiocyanate. The remaining thiocyanate is reacted with iron(III) to form a red iron(III)-thiocyanate complex which gave maximum absorbance at 460 nm. The concentration of mercury(II) is inversely proportional to the decrease absorbance of the complex. The method was optimized to the concentrations of thiocyanate and iron(III). Selectivity of the method has also studied based on percent recovery of mercury(II) in the presence of common metal ions in the tailing waters of gold mine. Under the optimum conditions, the method showed linear correlation to mercury(II) concentration from 1-30 mg L−1 with detection limit of 0.58 mg L−1. The method was not interfered in the presence of all metal ions studied up to 50 mg L−1, except of silver which was tolerated at 10 mg L−1. The developed method has been satisfactorily applied for mercury(II) determination in synthetic and tailing waters of gold mine samples.
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