کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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744600 | 894394 | 2007 | 5 صفحه PDF | دانلود رایگان |
The determination of hardness in water is a useful parameter to control the quality of water for households and industrial uses. The present work proposes a new methodology as an alternative to the conventional EDTA titration. The determination of Ca2+ and Mg2+ is performed using two different coated piezoelectric quartz crystals. Poly(vinyl chloride) membranes, incorporating a plasticizer and a Mg or Ca ionophore were used to coat the piezoelectric quartz crystals.Results obtained by this new methodology shows that the tap water found in Portugal can be considered soft in Gouveia (9.4 ± 0.8 mg L−1 CaCO3) and in Vila Praia Âncora (15 ± 1 mg L−1 CaCO3), slightly hard in Leiria (59 ± 1 mg L−1 CaCO3), moderately hard in Aveiro (74 ± 1 mg L−1 CaCO3) and in Esposende (104 ± 1 mg L−1 CaCO3) and very hard in Tomar (225 ± 1 mg L−1 CaCO3). The results obtained by the proposed method are not significantly different (α = 0.05), both in terms of accuracy and precision, from the ones obtained by the conventional EDTA titration method. Besides providing individual concentration of Ca2+ and Mg2+, this new methodology also has the advantage of being less reagent, sample and time consuming.
Journal: Sensors and Actuators B: Chemical - Volume 127, Issue 1, 20 October 2007, Pages 102–106