Full length articleAnalysis of phenolic acids by ionic liquid-in-water microemulsion liquid chromatography coupled with ultraviolet and electrochemical detector

- A green ionic liquid-in-water microemulsion was applied as mobile phase in microemulsion liquid chromatography.
- The proposed method involves the use of ultraviolet and electrochemical detector.
- Highly sensitive and selective separation performance of phenolic acids in Danshen and its preparation was achieved.
- The proposed method is a simple, sensitive, effective and environmental friendly.

An environmentally friendly ionic liquid-in-water (IL/W) microemulsion was established and applied as mobile phase in microemulsion liquid chromatography (MELC) with ultraviolet (UV) detection or electrochemical detector (ECD) for analysis of phenolic compounds in real samples. The optimal condition of the method was using the best composition of microemulsion (0.2% w/v [HMIM]PF6, 1.0% w/v SDS, 3.0% w/v n-butanol, 95.8% v/v water, pH 2.5) with UV detection. The validation results indicated that the method provided high degree of sensitivity, precision and accuracy with the low limit of detections ranged from 17.9-238 ng/mL, satisfactory mean recovery values in the range of 80.1-105% and good linearity (r2 > 0.9994). Additionally, this method exhibited high selectivity and resolution for the analytes and was more eco-friendly compared with traditional MELC method. Consequently, the established IL/W MELC method was successfully applied to simultaneously separate and determine target compounds in Danshen sample and its preparation.