A Novel Extraction Procedure for Stir Bar Sorptive Extraction (SBSE): Sequential SBSE for Uniform Enrichment of Organic Pollutants in Water Samples
A novel stir bar sorptive extraction (SBSE) procedure – “Sequential SBSE” was developed. Compared to conventional SBSE, sequential SBSE provides more uniform enrichment over the entire polarity/volatility range for organic pollutants at ultra-trace levels in water. Sequential SBSE consists of a SBSE performed sequentially on a 5-mL sample first without modifier using one stir bar, then on the same sample after addition of 30 % NaCl using a second stir bar. The method showed good linearity (r2 > 0.9900) and high sensitivity (limit of detection: < 10 ng/L) for most of the model compounds even with the scan mode in the MS. The method was successfully applied to screening of pesticides at ng/L level in river water samples.