Development of an SPME/ATR-IR chemical sensor for detection of phenol typecompounds in aqueous solutions

A new method, based on a combination of solid phase micro-extraction (SPME) and attenuated total reflection infrared (ATR-IR) spectroscopy, was develo ped for the detection of phenols in aqueous solutions. Several types of phe nols were studied including phenols attached to methyl, hydroxyl, chlorine and nitro groups, which are environmentally toxic. Because of the polarity of the phenol-type compounds, the performance of six polymers in attracting phenols was investigated. Results indicated that poly(acrylonitrile-co-but adiene) was the most suitable SPME phase among the investigated polymers. T o further increase the sensitivity in phenol detection, factors, such as th e pH effect, salt effect and thickness of the SPME phase, were investigated . Results indicated that pH values affected the neutral form percentage of the analytes strongly and, hence, affected the detected signals. Due to the acid nature of phenols, phenol detection occurs best in solutions with a l ow pH value. A two- to three-fold increase in signals was observed after th e addition of salt into the solution. The results on the examination of sta ndard curve linearity indicated that the regression coefficients (R-2) were higher than 0.996 for four types of phenols. The obtained detection limits for phenols were lower than 200 mug L-1 for most of the compounds.