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61.
A new procedure is described for the derivatization by silylation of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THCCOOH) present in urine, followed by analysis using gas chromatography–tandem mass
spectrometry. A conventional procedure for derivatization of the analyte was evaluated using two types of experimental design.
A 23 factorial design considered the parameters temperature, reaction time, and the solvent/derivatization agent ratio. A central
composite design (CCD) was applied to optimize the values of the significant variables. The optimum conditions were a reaction
temperature of 50 °C, a reaction time of 30 min, and a BSTFA/acetone ratio of 40:20. The use of imidazole as a catalyst, together
with ultrasonication, reduced the reaction time to 5 min and increased the efficiency of derivatization of THCCOOH, compared
with the conventional method. The operating conditions of the tandem mass spectrometer were also optimized. The method was
linear in the concentration range 1–50 ng mL−1 (R
2 = 0.9951). Intra- and inter-day precisions were 7.7–12.3% and 11.1–13.9%, respectively, recoveries ranged between 91 ± 8%
and 101 ± 12%, accuracy (as % bias) was between –11.7% and +0.7%, and limits of detection and quantification were 0.5 and
1.0 ng mL−1, respectively. 相似文献
62.
Kenan DJ Walsh EB Meyers SR O'Toole GA Carruthers EG Lee WK Zauscher S Prata CA Grinstaff MW 《Chemistry & biology》2006,13(7):695-700
Amphiphilic macromolecules containing a polystyrene-adherent peptide domain and a cell-repellent poly(ethylene glycol) domain were designed, synthesized, and evaluated as a cytophobic surface coating. Such cytophobic, or cell-repellent, coatings are of interest for varied medical and biotechnological applications. The composition of the polystyrene binding peptide domain was identified using an M13 phage display library. ELISA and atomic force spectroscopy were used to evaluate the binding affinity of the amphiphile peptide domain to polystyrene. When coated onto polystyrene, the amphiphile reduced cell adhesion of two distinct mammalian cell lines and pathogenic Staphylococcus aureus strains. 相似文献