Surfactant enhanced flow injection chemiluminescence method for vitamin D3 determination in pharmaceutical formulations

A flow injection based chemiluminescence process has been reported for vitamin D₃ determination without using especial chemiluminescence reagent. Vitamin D₃ shows enhancement on the CL intensity of diperiodatocuprate(III) with surfactant (Triton X-100) solution. The calibration curve was found to be linear over the concentration range 0.01-40 mg/L (R² = 0.9997, n = 8) tested. A limit of detection (S/N = 3), limit of quantification (S/N = 10) and sample injection throughput of 2.5 × 10^-3, 8.3 × 10^-3 mg/L and 150 h^-1 respectively were obtained. Various experimental variables were tested to get most suitable response, e.g., the concentrations of reagents, and their flow rates, sample injection volume and photomultiplier tube voltage. The effect of potential interferences was also examined. Vitamin D₃ determination was successfully carried out in pharmaceutical formulations. The recoveries from the formulations were obtained in the range of 96 ± 4-108 ± 2%. The reaction mechanism discussion for diperiodatocuprate(III) complex-Triton X-100-vitamin D₃ was also included.

Development of a novel chemiluminescence method for the determination of cefazolin sodium in injectable powder and human urine based on a luminol-Cu(III) complex reaction in alkaline medium

A novel chemiluminescence (CL) method was developed for the determination of cefazolin sodium based on the CL reaction between the [Cu(HIO6)2](5-) Cu(III) complex and luminol in alkaline solution. Results showed that CL emission of Cu(III) complex-luminol in alkaline medium was significantly different from that in acidic medium. A possible mechanism of the enhanced effect of cefazolin on CL emission of the [Cu(HIO6)2](5-)-luminol system was proposed. The effect of the reaction conditions on CL emissions was examined. Under optimized conditions, a good linear relationship was obtained between CL intensity and concentrations of cefazolin sodium in the range of 2.0 x 10(-8) to 2.0 x 10(-6) g/mL with a correlation coefficient of R(2) = 0.9978. The limit of detection was 4.58 x 10(-9) g/mL. The proposed method was applied for the determination of cefazolin sodium in real samples with recoveries of 82.0-109% with an RSD of 0.7-2.1%. The proposed method was successfully used for the determination of cefazolin sodium in injectable powder preparations and human urine with satisfactory results.