USE OF PROTEIN COATINGS ON PIEZOELECTRIC CRYSTALS FOR ASSAY OF GASEOUS POLLUTANTS

Preliminary studies utilizing biological substrates, such as enzymes and antibodies, as coatings for a piezoelectric crystal detector have proven successful. Immobilization of cholinesterase and parathion antibodies allows for the detection of organophosphorous pesticides at the ppb level with the cholinesterase coatings exhibiting a more specific response to parathion. Excellent reproducibilities, coating lifetimes, response times and selectivities are observed. This research is the first use of proteins as coatings for the direct assay of gaseous compounds, thus making this method an attractive alternative to some conventional techniques currently in use

Supercritical Fluid Extraction and Chromatography of Lipids in Bilberry.

A supercritical fluid extraction (SFE) method has been developed for the extraction of lipids in bilberry. Experimental design was used to optimize pressure, temperature and extraction time using CO2 as solvent. Best SFE condition for total lipids was 450 bar, 60 °C and 45 min. The SFE method was compared to conventional Bligh & Dyer (B&D) extraction. The amount of fatty acid methyl esters (FAME) was found to be 4.84 ± 0.06 mg and 4.564 ± 0.003 mg per g of the freeze-dried bilberry sample for the developed SFE and B&D methods, respectively, while the amount of total lipids was found to be 54.40 ± 6.06 mg and 65.70 ± 0.67 mg per g of sample for SFE and B&D, respectively. This discrepancy between FAME and total lipids could be explained by the presence of wax esters, sterol esters, carotenoids and phospholipids, as determined by supercritical fluid chromatography