Browse Prior Art Database

POWDER CHROMATOGRAPHY

IP.com Disclosure Number: IPCOM000027116D
Original Publication Date: 1995-Apr-30
Included in the Prior Art Database: 2004-Apr-07
Document File: 2 page(s) / 105K

Publishing Venue

Xerox Disclosure Journal

Abstract

A process for determining the purity of solvent insoluble dyes or pigments is disclosed. The process comprises inserting a sample of a dry dye or pigment particles within a dammed region at the center of a silica gel coated chromatographic plate, adding sufficient solvent to the dammed region in which said dye or pigment is insoluble, but in which impurities in the dye or pigment are soluble, wherein said solvent separates soluble impurities chromatographically from the dye or pigment, removing the solvent by drying, and subjecting the developed impurities to fluorescence or quenching analysis.

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XEROX DISCLOSURE JOURNAL

POWDER CHROMATOGRAPHY Proposed Classification Emery G. Tokoli US. C1.430/059 Edward F. Grabowski
C1. Int. Kathleen M. Carmichael G03g 05/06

A process for determining the purity of solvent insoluble dyes or pigments is disclosed. The process comprises inserting a sample of a dry dye or pigment particles within a dammed region at the center of a silica gel coated chromatographic plate, adding sufficient solvent to the dammed region in which said dye or pigment is insoluble, but in which impurities in the dye or pigment are soluble, wherein said solvent separates soluble impurities chromatographically from the dye or pigment, removing the solvent by drying, and subjecting the developed impurities to fluorescence or quenching analysis.

DETAILED METHOD

1) A 10 X 10 cm Thin Layer Chromatographic glass plate coated with Silica Gel 60 (and F254 fluorescent indicator) for Nano-HPTLC is placed flat, with gel side up. In the center of the plate, a glass Raschig ring (10 mm diameter) is placed. this ring is open on top and bottom as an upright cylinder and serves as a retaining container for the pigment or dye sample.

2) A small amount (several milligrams) of the dry powder dye or pigment sample is placed within the Raschig ring reaching about two-thirds of the height of the flat ring.

3) After selecting a suitable solvent for removing or dissolving surface impurities and the like from the dye or pigment, solvent extraction and development is carried out by adding this solvent carefully dropwise onto the sample, wetting it and keeping it moist while not overflowing the Raschig ring. The solvent acts as the chromatographic developi...