Author(s): Thavrin Manickum, Wilson John, Mncedisi Philip Malungana
A novel, fully validated, purge-and-trap sampling method, with gas chromatography-mass spectrometric detection for simultaneous quantitation of geosmin (GSM) and 2-methylisoborneol (2-MIB) was developed. The procedure involved purging a 25 mL sample volume, containing 1% (v/v) methanol, at 60Â°C for 20 min. Quantitation was done by separation on an HP 5-MS capillary column (30 m x 0.25 mm x 0.25 Âµm), followed by mass spectrometric detection in the selected ion monitoring (SIM) mode and a multiplier voltage of 400 mV above the auto tune setting. The method was reproducible (RSD <15%) and linear (r2 = 0.995) over the calibration range (5-100 ng/L). The relative recoveries of analytes from potable and raw water were between 80 and 120%; limits of quantitation (LOQ) achieved were 4 ng/L and 7 ng/L, for GSM and 2-MIB, respectively.