Apparatus design for rapid microchromatographic method of analysis of high molecular weight alkylphenols

Abstract

1. Tests of various columns for a rapid microchromatographic method of analysis of commercial alkylphenol fractions, and of a collector design for receiving the eluate fractions and distilling off the eluents, have shown the following: a) A downflow column with treated [scratched] inner surface, in comparison with an identical column without treatment, gives a higher efficiency of separation and better repeatability of parallel test results; this shows up in a lower relative mean square error in determining the component-groups and in a smaller loss in separation, especially when using silica gel with a broad range of particle size. b) The use of an upflow column with treated inner surface did not show any appreciable advantages over a similarly treated downflow column. c) The proposed collector design for receiving the eluate fractions and distilling off the eluents, in comparison with collection of the fractions on glass plates, reduces the total separation losses to 1–2.5% without any appreciable increase in the time required for the entire determination. 2. A study of the separation effect obtained with a mixture of two alkylphenols in vertical downflow columns with treated and untreated surfaces has shown the following: a) The treated column gives the better separation of a mixture of 2-octadecylphenol and 2-nonylphenol. b) The number of theoretical plates N, determined with octyl phenyl ether and with 2-nonylphenol, is 22.5% higher for the treated column. 3. From the data obtained in tests of various column designs for the rapid microchromatographic analysis of commercial alkylphenol fractions, a vertical downflow column, 85 cm in length and 3.2 mm in inside diameter, with treated inner surface, can be recommended as one of the most efficient and yet one of the simplest designs with respect to fabrication and operation.