| 摘要 |
The invention describes the process by which a standard mixture of organic compounds are spiked and retained onto a composite sorbent matrix for the controlled generation of a standard in fluid above the spiked matrix either in gas (headspace) or aqueous phase which is contained in portable vials. The novelty of the aforementioned composite matrix stems from the combination of an immobilizing liquid phase such as silicone oil or a polyacrylonitrile solution, and solid, porous particles such as polystyrene-co-divinylbenzene (PS-DVB) or Hydrophilic/Lipophilic Balance (HLB) particles to strongly retain the spiked standards facilitating high capacity which translates into prolonged use as a source of calibrant. These novel composite mixtures exhibit sorptive capabilities greater than the sum of their individual components producing a standard analyte generator far superior to those described in the prior art. In addition swelling of the particles with the liquid phase facilitates immobilization of the composite sorbent matrix in the vial. Immobilization of said particles has also been achieved by cross-linking of a liquid polymeric solution such as polydimethylsiloxane (PDMS), allowing the composite sorbent matrix to be uniformly distributed on the vessel wall. With thermodynamic equilibrium strongly favoring the sorbent phase for a wide range of chemical compounds, this invention allows for the reproducible generation of an ultra-low concentration standard analyte mixture in fluid. If the fluid is gaseous, extractions from this headspace can be performed via solid phase microextraction (SPME), needle trap devices (NTD), or direct headspace extraction for injection onto various hyphenated gas chromatography (GC) systems. If the fluid is aqueous, extractions may be performed directly from the standard water for injection onto hyphenated GC or liquid chromatography (LC) systems. The invention can be used for a variety of applications ranging from integrated GC-MS or LC-MS tuning, automated instrument quality control (QC), preparation of reusable external calibration mixtures and, addition of internal standards wherein the method provides long-term stability, inter-batch reproducibility, repeatable analyte loading of the fluid, and quantifiable low concentrations at given temperatures. |
