Development of chemiluminescence method for determination of 10-hydroxycamptothecin based on luminol-[Ag(HIO6)2]5− reaction in alkaline solution

A chemiluminescence reagent free method for the determination of captopril in medicine and urine samples by using trivalent silver

A novel flow-injection chemiluminescence (FI-CL) method free of CL reagent was developed for the determination of captopril based on its enhancing effect on the CL derived from diperiodatoargentate(III)-sulfuric acid system. Compared with the conventional CL system, the CL system based on trivalent silver was characterized of good selectivity for the absence of CL reagent. The CL mechanism was discussed through CL spectra and UV-vis absorption spectra. The conditions of the FI-CL system were investigated and optimized. Under the optimal conditions, the relative CL intensity was linear with the captopril concentration in the range of 0.3-15.0 μg/mL. The detection limit for captopril was 0.05 μg/mL, and the relative standard deviation (n=11) was 2.0% for 5.0 μg/mL captopril. The proposed method was applied to the analysis of captopril in tablet and human urine with the recoveries of 83.1%-112.5%, and the relative standard deviations of 0.5%-4.4%. The results obtained by the proposed method agreed well with those obtained from HPLC method. The proposed method is fast, convenient, and cost-effective for the determination of captopril in medicine and biological samples.

Sensitive determination of norepinephrine, epinephrine, dopamine and 5-hydroxytryptamine by coupling HPLC with [Ag(HIO6 )2 ](5-) -luminol chemiluminescence detection

Based on the enhancing effects of norepinephrine (NE), epinephrine (EP), dopamine (DA) and 5-hydroxytryptamine (5-HT) on the chemiluminescence (CL) reaction between [Ag(HIO6 )2 ](5-) and luminol in alkaline solution, a high-performance liquid chromatography (HPLC) method with CL detection was explored for the sensitive determination of monoamine neurotransmitters for the first time. The UV-visible absorption spectra were recorded to study the enhancement mechanism of monoamine neurotransmitters on the CL of [Ag(HIO6 )2 ](5-) and luminol reaction. The HPLC separation of NE, EP, DA and 5-HT was achieved with isocratic elution using a mixture of aqueous 0.2% phosphoric acid and methanol (5:95, v/v) within 11.0 min. Under the optimized conditions, the detection limits of NE, EP, DA, and 5-HT were 4.8, 0.9, 1.9 and 2.3 ng/mL, respectively, corresponding to 17.6-96.0 pg for 20 μL sample injection. The recoveries of monoamine neurotransmitters in rat brain were >95.6% with the precisions expressed by RSD <5.0%. The validated HPLC-CL method was successfully applied for the quantification of NE, EP, DA and 5-HT in rat brain. This method has promising potential for some biological and clinical investigations focusing on the levels of monoamine neurotransmitters. Copyright © 2016 John Wiley & Sons, Ltd.

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.