A Novel Chemiluminescence Assay of Ethylene Glycol in Antifreeze Samples using FIA with Merging Zone Principle

Aims: Chemiluminescence determination of ethylene glycol.
Place and Duration of Study: Samples: Antifreeze samples purchased from markets (Erbil, Kurdistan region, Iraq), between April 2011 and August 2011.
Methodology: A novel chemiluminescence (CL) reaction was based on the oxidizing reaction of luminol by in situ generated bromine in alkaline medium. The CL intensity could be inhibited in the presence of ethylene glycol (EG). A new CL method was developed for the determination of EG by coupling with flow injection analysis (FIA) with merging zone principle. Because of the toxic and corrosive nature, difficult handling and high reactivity, which results in highly exothermic and non-selective reactions of bromine, the bromine (Br2) will be generated in situ via the oxidation of hydrobromic acid (HBr) with hydrogen peroxide (H2O2).
Results: The relative CL intensity was proportional to the concentration of EG in the range of 35–440 µg/ml with the detection limit of 32 µg/ml and correlation coefficient of 0.9979. The relative standard deviation was 0.82% for 200 µg/ml EG.
Conclusion: The proposed method was successfully applied to the indirect determination of EG at the level of µg/ml in antifreeze samples. The error varied from –4.88% to 2.76%. A possible mechanism of the CL reaction was discussed by relating to the CL kinetic characteristics.