Hexane organic trace analysis

In most of the applications of LLE to phthalate analysis, extraction was performed in discontinue mode using separatory funnels. Table 28.5 summarizes some applications of this technique to phthalate analysis.In most cases, the volume of sample extracted is large (from O.I to 5 I). Frequently, samples are acidified and NaCI is added to favor the transfer of the analytes into the organic solvent. The solvents most frequently used are dichloromethane and hexane. In most cases, the extracts are dried with anhydrous sodium sulphate and concentrated to achieve high sensitivity. Nevertheless, the concentration factor is limited due to the presence of trace levels of phthalates in commercially available solvents, even in solvents for trace analysis. In consequence, accurate determinations below O.I /rg/I are questionable with this extraction technique. The extracts obtained are usually analyzed without a cleanup step. 

Liver portions (tip and mid-ventral blubber samples) of seals from the pack-ice of Queen Maud Land were analyzed for their contents in trace elements (Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Zn) and chlorinated hydrocarbon residues (DDE, DDT, dieldrin, PCBs, TDE) (72). Samples were stored at -20°C pending analysis. The metals were quantified by AAS after digestion, as appropriate. The organic compounds were first extracted with hexane, cleaned-up and then assayed by gas-liquid chromatography with EC detection. Concentrations in the high pg g level... 

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