Processing gas chromatographic data and confidence interval calculation for partition coefficients determined by the phase ratio variation method.
The phase ratio variation (PRV) method is widely used for the determination of partition coefficient values (dimensionless Henry's law constants) by headspace gas chromatography. Traditional data processing by linear regression has several drawbacks: potential bias introduced by linearization, absence of quality indicator of the resulting value and, in case of replicate determinations, poor utilisation of the existing measurements leading to unnecessarily large confidence intervals. The paper compares existing PRV data processing methods (linear and nonlinear regression, parametric) and derives confidence intervals for the resulting partition coefficient values. The possibility of using several series of measurements to derive a single partition coefficient value with tighter and more reliable confidence intervals is presented for all three processing methods. The methods are tested on published literature data and new experimental data for 12 volatile organic compounds in water at 25 degrees C. The nonlinear regression based on several series of measurements appears to be the method of choice.
Atlan
Samuel
S
UMR Génie et Microbiologie des Procédés Alimentaires, INRA INA P-G, BP 01, 1 Avenue Lucien Bretignères, F-78850 Thiverval-Grignon, France.
Trelea
Ioan Cristian
IC
Saint-Eve
Anne
A
Souchon
Isabelle
I
Latrille
Eric
E
D002849:Chromatography, Gas / Q000379:methods*; D016001:Confidence Intervals; D008433:Mathematics; D009930:Organic Chemicals / Q000737:chemistry*; D004364:Pharmaceutical Preparations / Q000032:analysis*; D012044:Regression Analysis; D012995:Solubility; D013696:Temperature; D014835:Volatilization
D009930:Organic Chemicals; D004364:Pharmaceutical Preparations