A simple and effective method for elimination the interference from nitrate ions on oxalic acid in RP-HPLC by solid-phase extraction with rock phosphate was developed. Rock phosphate is a cost-effective and environmentally friendly mineral material; it exhibited good adsorption ability for oxalic acid, other than nitrate ions, malic, or citric acid; therefore, rock phosphate could be used as an excellent solid-phase extractor for solving interference from nitrate ions on oxalic acid in RP-HPLC. The optimum experimental conditions for the separation and determination of organic acids were studied. After the interference was eliminated, oxalic acid was determined by RP-HPLC at the optimum chromatographic conditions with an average recovery ranging between 96.2% and 100.2%; the relative standard deviations (RSD) were less than 3.0%. This method was successfully applied to determine the oxalic acid in xylem sap of pokeweed.

Item Type:	Refereed Article
Keywords:	nitrate, oxalic acid, rock phosphate, RP-HPLC, separation, solid-phase extraction
Research Division:	Chemical Sciences
Research Group:	Analytical Chemistry
Research Field:	Separation Science
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in the Chemical Sciences
Author:	Wei, Z (Professor Zhenggui Wei)
ID Code:	91130
Year Published:	2013
Web of Science® Times Cited:	1
Deposited By:	Austn Centre for Research in Separation Science
Deposited On:	2014-05-08
Last Modified:	2014-08-05
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