The direct detection of clenbuterol(CL) in pig liver without any extraction separation at a pyrrole-DNA modified boron-doped diamond(BDD) electrode is reported. The pyrrole-DNA modified BDD electrode has a strong electrocatalytic effect on the redox reaction of CL. One oxidization and two reduction peaks of CL appear at 340.2, 299.8 and 166.6 mV(versus SCE), respectively. The pyrrole polymer alone cannot electrocatalyze the above reaction at a BDD electrode; the electrocatalytic effect of a BDD electrode modified with DNA membrane is unsufficient for the analytical detection of CL; the replacement of boron-doped diamond by glass carbon makes the electrocatalytic reaction impossible; the redox process is pH dependent. The influences of various experimental parameters on the pyrrole-DNA modified BDD electrode were investigated. A sensitive cyclic voltammetric response for CL was obtained in a linear range from 3.4×10^-6 to 5×10^-4 mol/L with a detection limit of 8.5×10^-7 mol/L. A mean recovery of 102.7% of CL in the pig liver sample solution and a reproducibility of 3.2% were obtained.
High performance liquid chromatography(HPLC) is one of the analytical techniques used most frequently. Its chief limitation lies in the need to avoid the overlap of chromatographic peaks as much as possible. In this paper, the overlapped chromatograms and spectra system of 1-chloro-2,4-dinitrobenzene and 3,5-dinitrobenzoic acid in the presence of 2,4-dinitrobenzoic acid were resolved by using the alternating trilinear decomposition(ATLD) combined with HPLC-DAD. Moreover, both were determined simultaneously, whose recoveries were(102.1±2.2)% and(97.6±3.6)%, respectively. The satisfactory results show that this experiment can be easily performed without paying out time-consuming and complicated procedures and quantifying accurately. It revealed the ATLD algorithm was one of the approaches to solve second-order calibration problem in HPLC-DAD.
