Replacing liquid chromatography with tailored ion chromatography: A green method for detecting furfuryl alcohol and understanding its properties

Abstract

Furfuryl alcohol (FFA) is a furan derivative potentially hazardous to human health, and it is now ubiquitously found in foods and used for identifying singlet oxygen (1O2) in environmental studies. However, current analytical methods for FFA in water are mostly based on gas chromatography and liquid chromatography (LC), which inevitably employ organic solvents as extractants or eluents that can result in harmful wastes production and extra treatment costs. To solve this issue, we herein developed a green analytical method to measure FFA without using organic solvents by a tailored ion chromatography (IC) equipped with ultraviolet (UV) detector. The method demonstrated a calibration curve fitting well (R2 > 0.99) for a wide FFA concentration range (i.e., 0.1 ∼ 10.0 mg/L) and a method detection limit (0.031 mg/L) comparable to LC method. The recoveries of FFA dosed into real samples exceeded 86.4% with the relative standard deviations below 2.5%. Next, we examined the property and reactivity of FFA through the method. It was found that FFA's acid-dissociation coefficient (i.e., pKa) was not 9.55, which disagrees with an earlier report. FFA was resistant to 254 nm UV or hydrogen peroxide (H2O2) but vulnerable to H2O2-assisted 254 nm UV or 185 nm vacuum UV, confirming that FFA was sensitive to hydroxyl radicals. Interestingly, FFA was degraded to less extent in water dosed with both sodium hypochlorite (NaOCl) and H2O2 than that dosed with NaOCl only, suggesting that the reaction between NaOCl and H2O2 does not produce 1O2. Given that this IC method can analyze FFA, NaOCl, and H2O2 simultaneously in one run, the evidences presented here may have helped clear a controversy about the 1O2 formation possibility by NaOCl and H2O2.