Determination of naphthenic acids in produced water by using microchip electrophoresis with integrated contactless conductivity detection

摘要: This study reports for the first time the use of a microchip electrophoresis (ME) device with integrated capacitively coupled contactless conductivity detection (C4D) to analyze naphthenic acids in produced water. A mixture containing 9-anthracenecarboxylic, 1-naphthoic, and benzoic acids was separated and detected using a running buffer composed of 10 mmol L−1 carbonate buffer (pH = 10.2). The separation was achieved within ca. 140 s with baseline resolution greater than 2 and efficiency values ranging from 1.9 × 105 to 2.4 × 105 plates m−1. The developed methodology provided linear correlation with determination coefficients greater than 0.992 for the concentration ranges between 50 and 250 µmol L−1 for benzoic and 9-anthracenecarboxylic acids, and between 50 and 200 µmol L−1 for 1-naphthoic acid. The achieved limit of detection values varied between 4.7 and 7.7 µmol L−1. The proposed …