A PCV-modified electrode was simply prepared by dip-coating a pyrolytic graphite electrode in a NaAc-HAc buffer solution of PCV. The peak currents of differential pulse voltammograms (DPV) decrease with the addition o...A PCV-modified electrode was simply prepared by dip-coating a pyrolytic graphite electrode in a NaAc-HAc buffer solution of PCV. The peak currents of differential pulse voltammograms (DPV) decrease with the addition of Al and the peak potentials remain the same. The decreasing of Delta i(p) is linear with Al concentration in the range of 1 x 10(-8) similar to 1 x 10(-7) mol/L. The detection limit is 5 x 10(-9) mol/L and the relative standard deviation for 4 x 10(-8) mol/L Al is 2.9% (n=8). No serious interference was found. The determination of Al in water samples is reported.展开更多
Four simple, sensitive and accurate spectrophotometric methods have been developed for the determination of some calcium channel blockers: Amlodipine besylate (ADB), Diltiazem hydrochloride (DTZ) and Verapamil hydroch...Four simple, sensitive and accurate spectrophotometric methods have been developed for the determination of some calcium channel blockers: Amlodipine besylate (ADB), Diltiazem hydrochloride (DTZ) and Verapamil hydrochloride (VPM) in pharmaceutical formulations. These methods based on formation ion pair complexes with Sulfochlorophenol-S (SCPS), Bromopyrogallol red (BPR), Eriochromecyanine- R (ECC) and Pyrocatechol violet (PCV) in acidic medium. The colored products are extracted with chloroform and measured spectrophoto- metrically at 462, 600, 440 and 442 for ECC, SCPS, BPR and PCV, respectively. Beer’s low was obeyed in the concentration range, for ECC: 25 - 175 μg·ml-1, 50 - 150 μg·ml-1 or 100 - 250 μg·ml-1, for SCPS: 300 - 800 μg·ml-1, 200 - 700 μg·ml-1 or 100 - 550 μg·ml-1, for BPR: 50 - 400 μg·ml-1, 200 - 700 μg·ml-1 or 200 - 700 μg·ml-1 for VPM, DTZ or ADB, respectively and for PCV: 50 - 250 μg·ml-1 for VPM or 200 - 500 μg·ml-1 for DTZ with molar absorptivity, for ECC: 2.2 × 104, 2.1 × 104, 1.6 × 104 L·mol-1·cm-1, for SCPS: 3.8 × 103, 5.6 × 103, 8.1 × 103 L·mol-1·cm-1, for BPR: 11 × 103, 4.8 × 103, 6.9 × 103 L·mol-1·cm-1 for VPM, DTZ or ADB, respectively and for PCV: 19.5 × 103 L·mol-1·cm-1 for VPM and 6.6 × 103 L·mol-1·cm-1 for DTZ and relative standard deviation, for ECC: 0.76%, 0.86%, 0.46%, for SCPS: 0.94%, 0.96%, 0.86%, for BPR: 0.96%, 0.95%, 0.55% for VPM, DTZ or ADB, respectively and for PCV: 0.81% for VPM and 0.65% for DTZ. These methods have been successfully applied for the assay of drug in pharmaceutical formulations. No interference was observed from common pharmaceutical adjuvants. Statistical comparison of the results with the reference method shows excellent agreement and indicates no significant difference in accuracy and precision.展开更多
文摘A PCV-modified electrode was simply prepared by dip-coating a pyrolytic graphite electrode in a NaAc-HAc buffer solution of PCV. The peak currents of differential pulse voltammograms (DPV) decrease with the addition of Al and the peak potentials remain the same. The decreasing of Delta i(p) is linear with Al concentration in the range of 1 x 10(-8) similar to 1 x 10(-7) mol/L. The detection limit is 5 x 10(-9) mol/L and the relative standard deviation for 4 x 10(-8) mol/L Al is 2.9% (n=8). No serious interference was found. The determination of Al in water samples is reported.
文摘Four simple, sensitive and accurate spectrophotometric methods have been developed for the determination of some calcium channel blockers: Amlodipine besylate (ADB), Diltiazem hydrochloride (DTZ) and Verapamil hydrochloride (VPM) in pharmaceutical formulations. These methods based on formation ion pair complexes with Sulfochlorophenol-S (SCPS), Bromopyrogallol red (BPR), Eriochromecyanine- R (ECC) and Pyrocatechol violet (PCV) in acidic medium. The colored products are extracted with chloroform and measured spectrophoto- metrically at 462, 600, 440 and 442 for ECC, SCPS, BPR and PCV, respectively. Beer’s low was obeyed in the concentration range, for ECC: 25 - 175 μg·ml-1, 50 - 150 μg·ml-1 or 100 - 250 μg·ml-1, for SCPS: 300 - 800 μg·ml-1, 200 - 700 μg·ml-1 or 100 - 550 μg·ml-1, for BPR: 50 - 400 μg·ml-1, 200 - 700 μg·ml-1 or 200 - 700 μg·ml-1 for VPM, DTZ or ADB, respectively and for PCV: 50 - 250 μg·ml-1 for VPM or 200 - 500 μg·ml-1 for DTZ with molar absorptivity, for ECC: 2.2 × 104, 2.1 × 104, 1.6 × 104 L·mol-1·cm-1, for SCPS: 3.8 × 103, 5.6 × 103, 8.1 × 103 L·mol-1·cm-1, for BPR: 11 × 103, 4.8 × 103, 6.9 × 103 L·mol-1·cm-1 for VPM, DTZ or ADB, respectively and for PCV: 19.5 × 103 L·mol-1·cm-1 for VPM and 6.6 × 103 L·mol-1·cm-1 for DTZ and relative standard deviation, for ECC: 0.76%, 0.86%, 0.46%, for SCPS: 0.94%, 0.96%, 0.86%, for BPR: 0.96%, 0.95%, 0.55% for VPM, DTZ or ADB, respectively and for PCV: 0.81% for VPM and 0.65% for DTZ. These methods have been successfully applied for the assay of drug in pharmaceutical formulations. No interference was observed from common pharmaceutical adjuvants. Statistical comparison of the results with the reference method shows excellent agreement and indicates no significant difference in accuracy and precision.
