Moment analysis for isolation of intrinsic column efficiencies in gas chromatography

Abstract

tions, one must independently account for these nonhydrocarbons. In spite of the (varying) contribution of noncondensed systems, the T N F technique provides chemical amplification for the predictive isolation of aromatic ring systems by adsorption chromatography. The true quantity of large ring aromatics is important in coal, petroleum, and environmental chemistry. Table I lists three different applications of this technique. These figures represent maximum levels of each system since ethers and thioether contaminants are present. Further study of the structure of these aromatic systems is now in progress.

Characterization of peak shape parameters with normal and derivative chromatograms

“…[ rh'(t2) + h(t2) J [ Th'(t2) + h(t2) J Th'(t2) + h(t2) "I rh'(t4) + h(t4) 1 [rh'(t3) + h(t3) \ [rh'(t3) + h(t3) \ (10) Rearranging eq 10 leads to a quartic equation of r in the simplified form 4 4 + 3 3 + 2 2 + 4 + a0 = 0 (11) Equation 11 also contains only peak heights at time points , t2, t3, and i4 in its coefficients. The value obtained from eq 11 permits the evaluation of a, íR, and A values using eq 9, 8, and 2 in sequence.…”

“…The chromatographic peak shape is governed by several factors such as the characters of the column material and the external operation conditions of the column. The simplest input profile of distribution is broadened asymmetrically and appears to be a skewed Gaussian form owing to the nonequilibrium mass transfer in column (1), dead volume (2), nonhomogeneity of tube connection (3), and time lag of the detector-amplifier system (4, 5).…”

“…EMGP can be expressed as the convolution of a Gaussian with an exponential decay function h(t) = _______A (2 ) /2 normal dt' (1) where A is the peak area, is the standard deviation of the Gaussian component, tR is the retention time of the Gaussian component, and is the time constant of the exponential modifier. In eq 1 the EMGP model is valid over the whole range of time t and characterized fully by four peak parameters, i.e., A, , o, and tR.…”