Development of a closed loop stripping analysis using solid-phase microextraction to analyze geosmin and MIB in drinking water

A novel analytical method, solid phase microextraction (SPME) coupled with closed loop stripping analysis (CLSA), was introduced for the analysis of MIB and geosmin at nanogram per liter concentration levels. The optimum CLSA/SPME analysis conditions of 65 °C, 60-minute extraction time, and 0.5 M sodium sulfate were determined from a statistical design. The individual K_fw of MIB and geosmin from CLSA/SPME method was 4.21 and 4.85, and resulted an order of magnitude greater than the K_fw obtained from direct SPME method. A detection limit of 10 ng/L of MIB and geosmin was achieved by GC-MS with CLSA/SPME with a polyacrylate phase. Overall, CLSA/SPME provides a fast, solvent-free, and less labor intensive method compared to the standard CLSA. The CLSA/SPME method is a valuable alternative method for the analysis of taste-and-odor causing compounds in drinking water.