Sample pretreatment and extraction

Abstract

A method for pretreating and extracting a liquid sample by sorbing an aqueous liquid sample, including an organic analyte and an acid or a base, in a solid sorbent material, and at least partially neutralizing the acid or base by reaction with neutralizing ions retained on a support surface, and contacting the liquid sample-sorbed sorbent material at elevated temperature and pressure with an organic solvent to extract the analyte into said solvent, preferably in a vessel having an extraction chamber with a zirconium metal interior surface.

1 . A method of pretreating and extracting a liquid sample including an organic analyte, said method comprising:
 (a) sorbing an aqueous liquid sample including an organic analyte and an acid or a base in a solid sorbent material, and at least partially neutralizing or precipitating said acid or base by reaction with neutralizing ions retained on a support surface, and   (b) contacting the liquid sample-sorbed sorbent material with an organic solvent to extract said analyte into said solvent.   
   
   
       2 . The method of  claim 1  in which said acid or base is partially neutralized in step (a). 
   
   
       3 . The method of  claim 1  in which said acid or base is precipitated in step (a). 
   
   
       4 . The method of  claim 1  in which said support surface is on said sorbent material. 
   
   
       5 . The method of  claim 4  in which said neutralizing ions are retained on said sorbent material surface by contacting said sorbent material with an acid, base, or precipitating reagent prior to said sorbing step and then at least partially drying said sorbent material. 
   
   
       6 . The method of  claim 4  in which said sorbent material further comprises a polymer including charged moieties on the polymer chain, wherein said neutralizing ions are counterions to said charged moieties electrostatically bound thereto. 
   
   
       7 . The method of  claim 1  in which said neutralizing ions comprise counterions to charged moieties covalently bound to said solid support surface. 
   
   
       8 . The method of  claim 1  in which said neutralizing ions comprise exchangeable ions and said support surface is on ion exchange medium. 
   
   
       9 . The method of  claim 1  in which said extraction is performed in a vessel having a zirconium metal interior surface. 
   
   
       10 . The method of  claim 1  in which said extracting is performed by accelerated solvent extraction. 
   
   
       11 . The method of  claim 1  in which said sorbent material is capable of absorbing substantially all the water in the said liquid sample. 
   
   
       12 . The method of  claim 1  in which said sorbent material is selected from the group consisting of diatomaceous earth, aluminum silicate, and sodium polyacrylate. 
   
   
       13 . The method of  claim 1  in which said organic analyte comprises an acid hydrolyzed lipid in a first layer and said liquid sample also includes acid in a second layer below and in contact with said first layer, said method comprising separating a substantial portion of said second layer from said first layer, and wherein said liquid sample sorbed in step (a) comprises said separated first layer. 
   
   
       14 . The method of  claim 1  further comprising detecting the extracted analyte of step (b). 
   
   
       15 . A method of extracting organic analytes from a liquid sample in a solid matrix, said method comprising extracting said organic analyte in an organic solvent at an elevated temperature and pressure in a vessel having a zirconium metal interior surface. 
   
   
       16 . A device for pretreating and extracting a liquid sample including an organic analyte, said device comprising a housing defining an extraction chamber, and a solid sorbent material and neutralizing ions retained on a support surface, said sorbent material and neutralizing ions being disposed in said extraction chamber. 
   
   
       17 . The device of  claim 16  in which said support surface is on said sorbent material. 
   
   
       18 . The device of  claim 17  in which said neutralizing ions are retained on said sorbent material by contacting said support surface with an acid or base and then at least partially drying said sorbent material. 
   
   
       19 . The device of  claim 17  in which said sorbent material comprises a polymer including charged moieties on the polymer chain, wherein said neutralizing ions are counterions to said charged moieties electrostatically bound thereto. 
   
   
       20 . The device of  claim 16  in which said neutralizing ions comprise counterions to charged moieties covalently bound to said support surface. 
   
   
       21 . The device of  claim 16  in which said neutralizing ions comprise exchangeable ions on ion exchange support medium. 
   
   
       22 . The device of  claim 16  in which said sorbent material is selected from the group consisting of diatomaceous earth, alumina silicate, and sodium polyacrylate. 
   
   
       23 . The device of  claim 16  in which the interior surface of said chamber comprises zirconium metal. 
   
   
       24 . An extraction device for use in accelerated solvent extraction comprising a vessel with an interior wall defining an extraction chamber, said interior wall being formed of zirconium metal. 
   
   
       25 . The device of  claim 24  further comprising an extraction mixture comprising an organic solvent and organic analyte retained in a solid material.