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A N Papas

Publications and source records attributed to A N Papas.

7 recordsLinked to original sources

Accuracy of peak deconvolution algorithms within chromatographic integrators.

The soundness of present-day algorithms to deconvolve overlapping skewed peaks was investigated. From simulated studies based on the exponentially modified Gaussian model (EMG), chromatographic peak area inaccuracies for unresolved peaks are presented for the two deconvolution methods, the tangent skim and the perpendicular drop method. These inherent inaccuracies, in many cases exceeding 50%, are much greater than those calculated from ideal Gaussian profiles. Multiple linear regression (MLR) was used to build models that predict the relative error for either peak deconvolution method. MLR also provided a means for determining influential independent variables, defining the required chromatographic relationships needed for prediction. Once forecasted errors for both methods are calculated, selection of either peak deconvolution method can be made by minimum errors. These selection boundaries are contrasted to method selection criteria of present data systems' algorithms.

Algorithms↗

Chemometric classification of reversed-phase high-performance liquid chromatography columns.

Cluster analysis and principal components analysis have been used to classify nine octadecyl (C18) high-performance liquid chromatography (HPLC) columns into three general groups displaying similar chromatographic behaviour. Principal components analysis was also able to identify the key test compounds on which the classification was most highly dependent. These identifications agreed with the classification and test compound selection by an HPLC specialist. In addition, the chemometric techniques can easily be extended to many more columns and test measurements than could be conveniently examined by a human expert.

Chemical Phenomena↗

Validation of high-performance liquid chromatographic methods for analysis of sustained-release preparations containing nitroglycerin, isosorbide dinitrate, or pentaerythritol tetranitrate.

The assay of sustained-release tablets or capsules containing nitroglycerin, isosorbide dinitrate, or pentaerythritol tetranitrate by high-performance liquid chromatography is described. Acetonitrile was found to be the sample preparation solvent with the most general applicability to these products. Anisole was used as an internal standard for nitroglycerin and pentaerythritol tetranitrate, while 4-chloroacetanilide was used for isosorbide dinitrate. The method, which uses a C18 bonded-phase column, a methanol-water mobile phase, and 214-nm detection, was shown to be accurate, linear, and reproducible.

Acetonitriles↗