|
authors |
Verissimo, MIS; Oliveira, JABP; Gomes, MTSR |
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journal |
SENSORS AND ACTUATORS B-CHEMICAL |
|
author keywords |
acoustic wave sensor; magnesium; calcium; hardness |
|
keywords |
QUARTZ-CRYSTAL MICROBALANCE; QUANTIFICATION; CALCIUM |
|
abstract |
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 Ancora (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 (alpha = 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. (c) 2007 Elsevier B.V. All rights reserved. |
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publisher |
ELSEVIER SCIENCE SA |
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issn |
0925-4005 |
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year published |
2007 |
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volume |
127 |
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issue |
1 |
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beginning page |
102 |
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ending page |
106 |
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digital object identifier (doi) |
10.1016/j.snb.2007.07.006 |
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web of science category |
Chemistry, Analytical; Electrochemistry; Instruments & Instrumentation |
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subject category |
Chemistry; Electrochemistry; Instruments & Instrumentation |
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unique article identifier |
WOS:000250691100016
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|
link |
http://dx.doi.org/10.1016/j.snb.2007.07.006
|
