1.Sub- and supercritical fluid extraction of trichloropyridinol from soil prior to immunoassay.
Jiménez-Carmona MM1, Manclús JJ, Montoya A, Luque de Castro MD. J Chromatogr A. 1997 Oct 17;785(1-2):329-36.
A comparative study on the extraction of TCP (3,5,6-trichloro-2-pyridinol, a metabolite of chlorpyrifos) from soil with CO2 and H2O is reported. The polarity of the analyte requires the presence of both a cosolvent (methanol) and an ion-pair reagent [(1R)-(-)-10-camphorsulfonic acid ammonium salt] for 95% extraction in 30 min when supercritical CO2 at 40 degrees C and 383 bar is used as extractant. Subcritical water (250 degrees C and 200 bar) enables complete extraction within 15 min without additives. Quantitation of the target analyte is performed by specific immunoassay using a non-commercial monoclonal antibody which provides a linear determination range between 0.005 and 5 micrograms/g, with coefficients of variation of 5.3 and 4.9% for the SC-CO2 and sub-H2O extractions, respectively.
2.Novel electrochemical method for the characterization of the degree of chirality in chiral polyaniline.
Feng Z1, Li M, Yan Y, Jihai T, Xiao L, Wanglin L. Chirality. 2013 Jan;25(1):39-42. doi: 10.1002/chir.22113. Epub 2012 Nov 23.
A novel method to indicate the degree of chirality in polyaniline (PANI) was developed. The (D-camphorsulfonic acid)- and (HCl)-PANI-based electrodes exhibited significantly different electrochemical performances in D- and L-Alanine (Ala) aqueous solution, respectively, which can be used for the characterization the optical activity of chiral PANI. Cyclic voltammogram, tafel, and open circuit potential of PANI-based electrodes were measured within D- and L-Ala electrolyte solution, respectively. The open circuit potentials under different reacting conditions were analyzed by Doblhofer model formula, in which [C(+)](poly1)/[C(+)](poly2) was used as a parameter to characterize the degree of chirality in chiral PANI. The results showed that [C(+)](poly1)/[C(+)](poly2) can be increased with increasing concentrations of (1S)-(+)- and (1R)-(-)-10-camphorsulfonic acid. In addition, we detected that appropriate response time and lower temperature are necessary to improve the degree of chirality.
