These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Sequential stir bar sorptive extraction for uniform enrichment of trace amounts of organic pollutants in water samples.
    Author: Ochiai N, Sasamoto K, Kanda H, Pfannkoch E.
    Journal: J Chromatogr A; 2008 Jul 18; 1200(1):72-9. PubMed ID: 18541254.
    Abstract:
    A novel extraction procedure for stir bar sorptive extraction (SBSE) termed 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 first extraction with unmodified sample is mainly targeting solutes with high Kow (logKow>4.0), the second extraction with modified sample solution (containing 30% NaCl) is targeting solutes with low and medium Kow (logKow<4.0). After extraction the two stir bars are placed in a single glass desorption liner and are simultaneously desorbed. The desorbed compounds were analyzed by thermal desorption and gas chromatography-mass spectrometry (TD-GC-MS). Recovery of model compounds consisting of 80 pesticides (organochlorine, carbamate, organophosphorus, pyrethroid, and others) for sequential SBSE was evaluated as a function of logKow (1.70-8.35). The recovery using sequential SBSE was compared with those of conventional SBSE with or without salt addition (30% NaCl). The sequential approach provided very good recovery in the range of 82-113% for most of the solutes, and recovery less than 80% for only five solutes with low Kow (logKow<2.5), while conventional approaches (with or without salt addition) showed less than 80% recovery for 23 and 41 solutes, respectively. The method showed good linearity (r2>0.9900) and high sensitivity (limit of detection: <10ngL(-1)) for most of the model compounds even with the scan mode in the MS. The method was successfully applied to screening of pesticides at ngL(-1) level in river water samples.
    [Abstract] [Full Text] [Related] [New Search]