Accurate approach for determining fresh-water carbonate (H ₂CO₃^*) alkalinity, using a single H ₃PO₄ titration point

TY - JOUR

T1 - Accurate approach for determining fresh-water carbonate (H 2CO3*) alkalinity, using a single H 3PO4 titration point

AU - Birnhack, Liat

AU - Sabach, Sara

AU - Lahav, Ori

N1 - Funding Information: The work was supported by a grant from ISF – Israel Science foundation

PY - 2012/10/15

Y1 - 2012/10/15

N2 - A new, simple and accurate method is introduced for determining H 2CO3* alkalinity in fresh waters dominated by the carbonate weak-acid system. The method relies on a single H3PO4 dosage and two pH readings (acidic pH value target: pH∼4.0). The computation algorithm is based on the concept that the overall alkalinity mass of a solution does not change upon the addition of a non-proton-accepting species. The accuracy of the new method was assessed batch-wise with both synthetic and actual tap waters and the results were compared to those obtained from two widely used alkalinity analysis methods (titration to pH∼4.5 and the Gran titration method). The experimental results, which were deliberately obtained with simple laboratory equipment (glass buret, general-purpose pH electrode, magnetic stirrer) proved the method to be as accurate as the conventional methods at a wide range of alkalinity values (20-400 mg L-1 as CaCO3). Analysis of the relative error attained in the proposed method as a function of the target (acidic) pH showed that at the range 4.0

AB - A new, simple and accurate method is introduced for determining H 2CO3* alkalinity in fresh waters dominated by the carbonate weak-acid system. The method relies on a single H3PO4 dosage and two pH readings (acidic pH value target: pH∼4.0). The computation algorithm is based on the concept that the overall alkalinity mass of a solution does not change upon the addition of a non-proton-accepting species. The accuracy of the new method was assessed batch-wise with both synthetic and actual tap waters and the results were compared to those obtained from two widely used alkalinity analysis methods (titration to pH∼4.5 and the Gran titration method). The experimental results, which were deliberately obtained with simple laboratory equipment (glass buret, general-purpose pH electrode, magnetic stirrer) proved the method to be as accurate as the conventional methods at a wide range of alkalinity values (20-400 mg L-1 as CaCO3). Analysis of the relative error attained in the proposed method as a function of the target (acidic) pH showed that at the range 4.0

KW - Alkalinity analysis

KW - Carbonate alkalinity

KW - Fresh water

KW - Single titration

UR - http://www.scopus.com/inward/record.url?scp=84869113554&partnerID=8YFLogxK

U2 - 10.1016/j.talanta.2012.08.024

DO - 10.1016/j.talanta.2012.08.024

M3 - 文章

C2 - 23141305

AN - SCOPUS:84869113554

VL - 100

SP - 12

EP - 20

JO - Talanta

JF - Talanta

SN - 0039-9140

ER -