期刊
ENVIRONMENTAL SCIENCE & TECHNOLOGY
卷 45, 期 11, 页码 4862-4868出版社
AMER CHEMICAL SOC
DOI: 10.1021/es200665d
关键词
-
资金
- NSF [OCE-0727082]
Spectrophotometric procedures allow rapid and precise measurements of the pH of natural waters. However, impurities in the acid base indicators used in these analyses can significantly affect measurement accuracy. This work describes HPLC procedures for purifying one such indicator, meta-cresol purple (mCP), and reports mCP physical-chemical characteristics (thermodynamic equilibrium constants and visible-light absorbances) over a range of temperature (T) and salinity (S). Using pure mCP, seawater pH on the total hydrogen ion concentration sale (pH(T)) can be expressed in terms of measured mCP absorbance ratios (R = lambda(2)A/lambda(1)A) as follows: pH(T) = log (K(2)(T)e(2)) + log (R - e(1)/1 - R e(3)/e(2)) where -log(Kr(2)(T)e(2)) = a + (b/T) cln T - dT; a = 246.64209 + 0.315971S + 2.8855 x 10(-4)S(2); b = 7229.23864 - 7.098137S - 0.057034S(2); c = 44.493382 - 0.052711S; d = 0.0781344; and mCP molar absorbance ratios (e(i)) are expressed as e(I) = 0.007762 + 4.5174 x 10(-5)T and e(3)/e(2)= 0.020813 + 2.60262 x 10(-4)T + 1.0436 x 10(-4) (S - 35). The mCP absorbances, lambda(1) A and lambda(2) A, used to calculate R are measured at wavelengths (lambda) of 434 and 578 nm. This characterization is appropriate for 278.15 <= T <= 308.15 and 20 <= S <= 40.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据