HPLC determination of oxalic acid using tris(1,10-phenanthroline)ruthenium(II) chemiluminescence—application to the analysis of spinach

• Published in: Food chemistry 1999-06, Vol.65 (4), p.543-546
• Main Authors: Wu, Fengwu, He, Zhike, Luo, Qingyao, Zeng, Yun’e
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Chemiluminescence; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; HPLC; Oxalic acid; Ru(phen) 32; Spinach
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/S0308-8146(98)00223-4

The chemiluminescence (CL) of Ru(phen) 3 2+ was applied to HPLC determination of oxalic acid. Oxalic acid was separated by a C 18 reverse-phase column with a mobile phase of 0.02 mol/l NH 4Ac. The eluted oxalic acid was mixed with 0.25 mol/l Ru(phen) 3 2+ and 2.0 mmol/l Ce(SO 4) 2 in 0.08 mol/l H 2SO 4, and then pass through a modified luminometer used as a detector. The reaction of Ce(IV) oxidized Ru(phen) 3 2+ and oxalic acid emitted light. The detection limit was 6.2×10 −6 mol/l for oxalic acid at a S/N ratio of 3, the relative standard deviation for 5 replicate injections of 1×10 −3 mol/l oxalic acid standard was calculated as 5.6%, and the linear calibration range was 1×10 −5 to 4×10 −3 mol/l. The method was successfully applied to determination of oxalic acid in spinach. ©