• Journal of the Korean Chemical Society
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• v.54 no.5
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• pp.556-566
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• 2010

A new kinetic spectrophotometric method is developed for the measurement of Mn(II) in natural water samples. The method is based on the catalytic effect of Mn(II) with the oxidation of Gallocyanin by $KIO_4$ using nitrilotriacetic acid (NTA) as an activation reagent at 620 nm. The optimum conditions obtained are $4.00{\times}1^{-5}\;M$ Gallocyanin, $KIO_4$, $1.00{\times}10^{-4}\;M$ NTA, 0.1 M HAc/NaAc buffer of pH = 3.50, the reaction time of 5 min and the temperature of $30^{\circ}C$. Under the optimum conditions, the proposed method allows the measurement of Mn(II) in a range of $0.1\;-\;4.0\;ng\;mL^{-1}$ and with a detection limit of down to $0.025\;ng\;mL^{-1}$. The recovery efficiency in measuring the standard Mn(II) solution is in a range of 98.5 - 102%, and the RSD is in a range of 0.76 - 1.25%. The newly developed kinetic method has been successfully applied to the measurement of Mn(II) in both some environmental water samples and certified standard reference river water sample, JAC-0031 with satisfying results. Moreover, few cations and anions interfere with the measurement of Mn(II). Compared with the other catalytic-kinetic methods and instrumental methods, the proposed kinetic method shows fairly good selectivity and sensitivity, low cost, cheapness, low detection limit and rapidity. It can easily and successfully be applied to the real water samples with relatively low salt content and complex matrices such as bottled drinking water, cold and hot spring waters, lake water, river water samples.

• Korean Journal of Food Science and Technology
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• v.43 no.5
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• pp.532-536
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• 2011

The internal standard method using ion chromatography combined with tandem mass spectrometry (IC-MS/MS) for quantifying perchlorate in different types of food was established. Because the presence of ions and other biomolecules in matrices usually interrupts accurate determination of perchlorate, it is necessary to develop efficient, reproducible method to determine perchlorate concentrations in food. In this study, the internal standard method was compared with the external standard method to determine perchlorate concentrations in standard samples. The obtained method detection limit (MDL) for perchlorate was 0.005 ${\mu}g/L$ for bottled water, 0.12 ${\mu}g/L$ for milk, 0.27 ${\mu}g/kg$ for rice, 0.16 ${\mu}g/kg$ for vegetables, and 0.07 ${\mu}g/kg$ for seaweed, respectively. The limit of quantitation (LOQ) was calculated by multiplying the MDL by 7. The recoveries of perchlorate from food samples spiked with perchlorate ranged from 98 to 105% and their percent relative standard deviation (%RSD) levels were <20%. This method was successfully applied for the quantitative determination of perchlorate in various kinds of food.