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Enzymatic Determination of Ammonia in Lake Water Using a Semi-Automatic Analyser |
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| Authors: | S. Hashimoto H. Y. Sun A. Otsuki S. Kawakami F. Murata M. Yokomizo |
| Affiliation: | 1. Department of Marine Science and Technology , Tokyo University of Fisheries , 4-5-7 Konan, Minato-ku, Tokyo, 108, Japan;2. Olympus Optical Co. Ltd. , 2-3 Kuboyama-chou, Hachiooji-shi, Tokyo, 192, Japan |
| Abstract: | Abstract An enzymatic method was developed for the determination of ammonia concentrations in lake water. Lake water samples containing ammonia were mixed with a glutamate dehydrogenase (GIDH), reduced nicotinamide adenine dinucleotide phosphate (NADPH) and 2-oxoglutarate. The decrease in the absorbance intensity caused by the disappearance of NADPH by this reaction was measured at 340 nm. There was a linear relationship (r = 0.9997) between peak height and ammonia concentration over the range 0–29 μM. The detection limit was 0.29 μM for a sample volume of 250 μl. Interference of amino acids and urea at concentrations of 50 mg l?1 was negligible. Good agreement was found between the enzymatic method and indophenol blue colorimetry. |
| Keywords: | Ammonia determination enzymatic method semi-automatic analyser lake water glutamate dehydrogenase |