Collaborative Study of a Gas Chromatographic Method for Phenothiazine in Drugs
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Abstract A rapid and specific gas chromatographic method for phenothiazine in microgram amounts has been developed and studied collaboralively. The phenothiazine is extracted from a ground sample with chloroform. An internal standard, promethazine hydrochloridc, is added to the extract and to a chloroform solution of phenothiazine standard. Both solutions are diluted and aliquots are chromatographed on a 4' column of Gas Chrom Q with a 5% coating of Apiezon L. Collaborative results, based on 18 separate analyses of each sample, were 38.2 ± 1.2% (38.2% added), and 42.2 ± 1.2% (43.1% added)