The Choice of Internal Standards for Measuring Volatile Pollutants in Water.

Autor: Jávorszky, E., Erdoedy, G., Torkos, K.
Zdroj: Chromatographia; Jun2006 Supplement, Vol. 63, pS55-S60, 1p
Abstrakt: 54 volatile pollutants have been examined by static headspace-gas chromatography-mass selective detection in order to find the proper internal standard for each of the pollutants examined. The applicability of the internal standards has been assessed mathematically. For modelling, we prepared 2 × 4 × 4 solutions using blank water with added sodium sulphate and humic acid at four different concentrations for each. These solutions were spiked with two different concentrations of dilute standard solutions. We also examined 44 real water samples for traces of the 54 volatile pollutants, spiking them with dilute standard solutions. The results of a single measurement were 54 quotients for relative extraction efficiency: the area of the pollutant divided by the corresponding area of the spiked blank water measurement. For each pair of pollutants, the Pearson correlation coefficients were calculated for both the model and real water samples. We regarded two pollutants as being the same, if their Pearson correlation coefficient was greater than 0.95. Among similar pollutants we selected candidates for being suitable internal standards based on the highest correlation coefficients. We found, that five compounds are sufficient to cover 49 pollutants. Two pollutants did not exhibit a matrix effect and for these only the external calibration method can be used. For three pollutants, special considerations apply.The measurement data generally verified that structurally similar compounds have high correlation coefficients, but there were exceptions among similar compounds and unexpected similarities were also found. Nothing was found in the literature on determining the proper internal standard using Pearson correlation coefficients. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index