Determination of Sulphate in Water by Die Technique and the Detection of Ca+2 and Mg+2 in their Mixture

Volume 10 , Issue 1 , November 2007 , Pages 103-111

Authors

¹ College of Science, University of Sulaimani

The new thermometric sensor developed in this laboratory (Talanta-2007,71(l),141-148) has Been

applied here for the determination of sulphate ion in water samples.A (20 ml) aliquot of standard or

natural watersampleacidified with (1 ml)of (lMHCl)isplaced inthe thermometric cell. The cell

is covered with the press-on lid, so that the sensor is completely covered by the liquid. The

vertical stirrer is placed down the cell and stirred, When the thermal equilibrium is recorded, (0.5 ml)

of (1.5M) barium acetate solution is injected rapidly by a syringe. The output signal is recorded

and measured as a peak height during (30 sec.) Following the injection, and also read from the digital

avometer, The calibration curve is drawn between (AmV) or (AT) vs. (ppm) sulphate. It was linear in

tle range (10 - 110) ppm sulphate with 12 = 0.9991. The method was used for the determination of

sulphate in different samples of water containing between 21 - 430 ppm with precision better than 5o4

and gave no significant difference when compared with a reference method at 95oh confidence limit

(DOF = 6) using t-test of paired comparison. In this paper another successful test of the sensor was

performed to evaluate its response fbr a mixture of Caz- and Mg2* ions.

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