Chemiluminescence determination of captopril based on a Rhodamine B sensitized cerium(IV) method

Recent Advances of Optical Sensors for Copper Ion Detection

A trace element copper (Cu²⁺) ion is the third most plentiful metal ion that necessary for all living organisms and playing a critical role in several processes. Nonetheless, according to cellular needs, deficient or excess Cu²⁺ ion cause various diseases. For all these reasons, optical sensors have been focused rapid Cu²⁺ ion detection in real-time with high selectivity and sensitivity. Optical sensors can measure fluorescence in the refractive index-adsorption from the relationships between light and matter. They have gained great attention in recent years due to the excellent advantages of simple and naked eye recognition, real-time detection, low cost, high specificity against analytes, a quick response, and the need for less complex equipment in analysis. This review aims to show the significance of Cu²⁺ ion detection and electively current trends in optical sensors. The integration of optical sensors with different systems, such as microfluidic systems, is mentioned, and their latest studies in medical and environmental applications also are depicted. Conclusions and future perspectives on these advances is added at the end of the review.

Green innovative fluorescence approach for the feasible and reliable assay of thiol-containing drugs; captopril as a model

In the present study, a novel spectrofluorimetric approach was designed for the analysis of captopril as a thiol-containing compound. The approach is based on the formation of a ternary fluorescent compound between the target thiol compound, ortho-phthaldehyde, and a suitable primary amine-containing compound. The produced 1-thio-alkyl-isoindole derivative exhibited very high emission activity in a faintly alkaline aqueous solution that could be monitored at 448 nm (excitation at 334 nm). 2-Amino-6-methyl-6-hydroxy-heptane was selected as the primary amine candidate that gave the high fluorescence intensity with the stability of the formed product. At the optimal experimental condition, the intensity of fluorescence of the formed product was linearly related to the concentration of captopril in 20-450 ng mL^-1 range. Commercial pharmaceutical tablets were analyzed, and the obtained results agreed with those of the published method regarding precision and accuracy. The mechanism of the reaction was discussed. In addition, the greenness of the approach was rated following eco-scale criteria.

A reaction-triggered luminescent Ce4+/Tb3+ MOF probe for the detection of SO2 and its derivatives

A novel reaction-responsive Ce⁴⁺/Tb³⁺ luminescent probe was designed and synthesized for sensing gaseous sulfur dioxide and its derivatives in human serum.

Energy transfer processes of chemiluminescence reaction systems with cerium(IV) ions and their analytical application: a review

This review is devoted to a thorough discussion of chemiluminescence of the systems containing Ce(IV) ions as oxidising agents, with particular emphasis on the energy transfer processes in such systems. The influence of sensitisers such as: rhodamines, quinine, lanthanide ions and their complexes and quantum-dots has been analysed and the practical use of reaction systems for development of new chemiluminescence methods for determination of therapeutic drugs and substances of biological importance in different matrices such as human urine or serum is indicated. The types of emitters and excited reaction products taking part in energy transfer to sensitisers and processes taking place in the chemiluminescence reaction systems containing Ce(IV) ions are presented on the basis of recent literature.

Determination of captopril by high-performance liquid chromatography with direct electrogenerated chemiluminescence

Captopril exhibit electrogenerated chemiluminescence (ECL) in NaNO(3) solution when constant current is exerted. Based on this observation, a direct ECL method coupled with high-performance liquid chromatography (HPLC) separation is developed for determination of captopril in human serum. Factors affected the ECL emission are investigated. Under the optimal conditions, the ECL intensity has a linear relationship with the concentration of captopril in the range of 4.0×10(-6)-2.0×10(-3) g mL(-1) and the detection limit is 2×10(-6) g mL(-1) (S/N=3). Compared with the common electrogenerated chemiluminescence experiments, the developed method need no any other fluorescence additives.

Chemiluminescence determination of cefotaxime sodium with flow-injection analysis of cerium (IV)-rhodamine 6G system and its application to the binding study of cefotaxime sodium to protein with on-line microdialysis sampling

A simple, sensitive and rapid flow-injection chemiluminescence (CL) method has been developed for the determination of cefotaxime sodium based on the chemiluminescence reaction of cefotaxime sodium with ceric sulfate and rhodamine 6G in nitric acid solution. The concentration of cefotaxime sodium was proportional with the CL intensity in the range of 4×10(-8)-8×10(-6) mol L(-1). The detection limit (signal-to-noise ratio=3) was 1×10(-8) mol L(-1). Coupled to the technique of on-line microdialysis sampling, this method was successfully applied to study cefotaxime sodium-protein interaction. The drug and protein were mixed in different molar ratios in Ringer's solution, pH 7.4, and incubated at 37°C in a water bath. The microdialysis probe was utilized to sample the mixed solution at a perfusion rate of 5 μL min(-1) and the recovery of cefotaxime sodium under experimental condition was 16.2%. The data obtained by the present Microdialysis-Flow Injection Analysis-CL method was analyzed with the Scatchard analysis and Klotz plot. The estimated association constant (K) and the number of the binding sites (n) on one of BSA molecule were 5.94×10(4) M(-1) and 1.29 (Klotz equation), respectively.

Voltammetric Determination of Captopril Using Chlorpromazine as a Homogeneous Mediator

Chlorpromazine was used as a homogeneous electrocatalyst in the oxidation of captopril. The anodic peak current of chlorpromazine was increased substantially in the presence of low concentrations of captopril (pH 4). Cyclic voltammetry and chronoamperometry were used to study the kinetics of the catalytic electron transfer reaction. The values of electron transfer coefficient () and catalytic rate constant () were estimated to be 0.34 and , respectively. Linear sweep voltammetry was used for the determination of captopril in the presence of chlorpromazine. A linear calibration curve was obtained in the concentration range of captopril of 10.0–300.0 μM, with a limit of detection of 3.65 μM. The relative standard deviation (RSD%) for 5 replicate measurements of captopril (100 μM) was 1.96%. The method was applied to the determination of captopril in pharmaceutical formulations and blood serum samples with satisfactory results.

Quantitative determination of bilirubin by inhibition of chemiluminescence from lucigenin

Bilirubin is a metabolic breakdown product of blood haem, of great biological and diagnostic importance. A new chemiluminescence (CL) method has been developed for the quantification of bilirubin. The method is combined with the flow injection analysis (FIA) technique and based on the inhibition effect of bilirubin on the CL from the lucigenin-hydrogen peroxide system in an alkaline medium. Under the optimum conditions, the decreased CL intensity was proportional to the concentration of bilirubin, in the range 0.0585-58.47 microg/mL. The detection limit estimated from the calibration graph was about 7.8826 ng/mL. The relative standard deviation (RSD) of 10 parallel measurements (1 x 10(-4) mol/L bilirubin) was 2.5%. Recoveries of bilirubin were found to fall in the range 94-97.5% using control sera. The method is interference-free, fast and easy to carry out.

Electrochemiluminescence determination of pipemidic acid using sulfite as energy transfer mediator

An electrochemiluminescence (ECL) based on energy transfer from electro-generated triplet sulfur dioxide to pipemidic acid (PPA) was studied. A weak ECL from triplet sulfur dioxide (3)SO2 * was observed when sulfite was electrochemically oxidized in sulfuric acid solution on a Pt electrode. When PPA was present, the weak ECL was enhanced. The enhanced ECL was attributed to energy transfer from (3)SO2 * to PPA. Based on the enhanced ECL, a flow-injection (FIA) ECL method for the determination of PPA was proposed. The proposed method allowed the measurement of PPA over the range of 1.0x10(-7) to 2.0x10(-5)moll(-1). The detection limit was 3.9x10(-8)moll(-1), and the relative standard deviation for 1.0x10(-6)moll(-1) PPA (n=9) was 1.3%. This method was evaluated by the analysis of PPA in pharmaceutical preparations and urine samples.

Enhanced plasmon resonance light scattering signals of colloidal gold resulted from its interactions with organic small molecules using captopril as an example

Gold nanoparticles are known for their plasmon resonance absorption (PRA) depending on their size. Our this investigation shows that plasma resonance light scattering (PRLS) signals in the corresponding PRA region could be measured using a common spectrofluorometer, and be enhanced when aggregation of gold nanoparticles occurs due to their interaction with organic small molecules (OSMs). Using captopril (Cap) as an example, we investigated the interactions of gold nanoparticles with OSMs in order to propose a general method of OSMs such as typical clinic organic drugs. In aqueous medium of pH 2.09, there are about 2.2 x 10(3) Cap molecules covalently binding to the surface of a 10-nm diameter gold nanoparticle through the thiol functional group of Cap, and thus forms a core-shell assembly of [(Au)(31000)]@[(Cap)(2200)], displaying strong enhanced PRLS signals in the PRA region of gold colloid. The PRLS intensities characterized at 553.0 nm were found to be proportional to the concentration of Cap over the range of 0.1-1.7 mg L(-1) with the determination limit (3sigma) of 32.0 microg L(-1). With that, Cap in pharmaceutical preparations could be determined with the recovery of 97.0-104.5% and R.S.D. of less than 2.4%.

Quantitative determination of captopril and prednisolone in tablets by FT-Raman spectroscopy

A procedure for the quantitative determination of captopril and prednisolone in commercial tablets based on partial least squares (PLS) and principal component regression (PCR) treatment of FT-Raman spectroscopic data is described. In the studied medicines active pharmaceutical ingredients (APIs) constitute 4.2-16.7% of the tablet mass. Results obtained from calibration models built using unnormalised spectra were compared with the values found when an internal standard was added to each sample and the spectra were normalised by its selected band intensity at maximum or integrated. To appraise the quality of the models the relative standard error of predictions (RSEPs) were calculated for calibration and testing data sets. For captopril determination these were 1.8-2.2% (2.1-2.3%) and 2.7-3.1% (2.7-3.6%), respectively for the different PLS (PCR) models. For prednisolone these errors amounted to 1.8-2.1% (2.6-3.5%) and 3.2-3.7% (3.7-5.9%), respectively. Three commercial preparations of captopril containing 12.5mg and one 25mg of API per tablet were quantified using developed models. Found captopril contents, calculated versus results of iodometric titration, was equal 99.2-101.2% (99.2-102.0%), for the different PLS (PCR) calibration models and the different preparations. Quantification of prednisolone tablets, declared content 5mg per tablet, on the basis of PLS (PCR) models gave API amount, calculated versus results of UV-vis method, in the 99.0-101.0% (98.0-102.0%) range.

Flow injection-chemiluminescence determination of puerarin in pharmaceutical preparations

Strong chemiluminescence was observed when cerium(IV) reacted with rhodamine 6G in sulfuric acid medium in the presence of puerarin. This phenomenon has been utilized to design a sensitive and selective flow injection-chemiluminescence method for the determination of puerarin. Under the optimum conditions, the proposed procedure has a linear range between 1.3 x 10(-9) and 8.0 x 10(-7)g/mL, with a detection limit of 8.4 x 10(-10)g/mL puerarin and a relative standard deviation of 1.86% (n = 11) at 5.0 x 10(-8)g/mL puerarin. The method was successfully applied to the determination of puerarin in pharmaceutical preparations. The mechanism of this chemiluminescence reaction has been proposed.

Flow-injection inhibition chemiluminescence determination of indapamide based on luminol–ferricyanide reaction

A novel and sensitive chemiluminescence (CL) method for the determination of indapamide coupled with flow-injection analysis (FIA) technique is developed in this paper. It is based on the inhibition effect of the studied drug on the chemiluminescence emission of luminol-potassium ferricyanide system. Under the optimum conditions, the decreased CL intensity is proportional with the concentration of indapamide in the range of 1 x 10(-8) to 1.0 x 10(-6) g ml(-1). The detection limit is 3.4 x 10(-9) g ml(-1) (3sigma). A complete analysis could be performed in 45 s including washing and sampling, giving a throughout of about 90 h(-1). The relative standard deviation (R.S.D.) for 11 parallel measurements of 1.0 x 10(-7) g ml(-1) indapamide is 3.0%. The proposed method has been applied for the determination of indapamide in its pharmaceutical formulations. The results obtained compared well with those by an official method. The possible inhibition mechanism of indapamide on luminol-potassium ferricyanide CL system was discussed briefly.

Flow-injection chemiluminescence detection for studying protein binding of terbutaline sulfate with on-line microdialysis sampling

The binding of terbutaline sulfate to bovine serum albumin was studied in vitro using the technique of microdialysis sampling combined with flow-injection chemiluminescence analysis (FIA-CL). In the presence of formaldehyde, terbutaline sulfate can be oxidized by KMnO(4) to produce high chemiluminescence emission in sulfate acid media. The concentration of terbutaline sulfate is proportional with the CL intensity in the range of 1 x 10(-7)-2 x 10(-5) mol l(-1) with a detection limit of 3 x 10(-8) mol l(-1). The drug and protein were mixed in different molar ratios in 0.067 mol l(-1) phosphate buffer, pH 7.4, and incubated at 37 degrees C in a water bath. The microdialysis probe was utilized to sample the mixed solution at a perfusion rate of 5 microl min(-1) and the dialytic efficiency of terbutaline sulfate under the experimental conditions was 26.3%. The data obtained by proposed microdialysis flow-injection chemiluminescence method was analyzed with Scrathard analysis and Klotz plot. The estimated association constant (K) and the number of the binding site (n) on one molecule of BSA by Scrathard analysis were 4.11 x 10(4) l mol(-1) and 1.06, respectively. The proposed system proved that FIA-CL coupled with on-line microdialysis sampling is a simple and reliable technique for the study of drug-protein interaction.

Flow-Injection Chemiluminescence Determination of Formaldehyde with a Bromate-Rhodamine 6G System

In this paper, a novel flow-injection chemiluminescence (CL) system for the determination of formaldehyde is described. It is based on a strong enhance effect of formaldehyde on the weak CL emission of the reaction between potassium bromate and rhodamine 6G in a sulfuric acid medium. A possible mechanism for this CL reaction is proposed. A CL calibration graph was linear in the range of 0.8 - 200 microg l(-1) and the detection limit was 0.3 microg l(-1) (3sigma). The relative standard deviation was less than 3% for 10 microg l(-1) formaldehyde (n = 11). The method has been applied to determine formaldehyde in the air samples.

Flow injection biamperometric determination of captopril

An automated method to determine captopril (1-[(2S)-3-mercapto-2-methylpropionyl]-L-proline) is proposed. A flow injection manifold based on the indirect biamperometric detection of the captopril by using Fe(III)/Fe(II) as an indicating redox system and a Z-shaped flow-cell configuration, was developed. The calibration curve is linear over the range 0.03-3.6 microg ml(-1) of captopril. The relative standard deviation for the determination of 0.76 microg ml(-1) of captopril is 0.97% (n = 12) and the sample throughput is 69 h(-1). This method was applied to the determination of captopril to commercially available pharmaceutical preparations.

Flow injection chemiluminescence determination of captopril based on its enhancing effect on the luminol-ferricyanide/ferrocyanide reaction

A new flow injection chemiluminescence method is described for the determination of captopril. It is based on the enhancing effect of captopril on the chemiluminescence reaction of luminol with potassium ferricyanide in alkaline solution in the presence of potassium ferrocyanide. The method allows the determination of captopril over 0.1-40 microg/mL range, with a relative standard deviation (SD) of 1.0% for the determination of 0.5 microg/mL captopril solution in 11 repeated measurements. The method was satisfactorily applied to the determination of captopril in commercial captopril tablets. The possible reaction mechanism is also discussed briefly.

Flow-chemiluminescence: a growing modality of pharmaceutical analysis

The present article deals with a review of the applications of the chemiluminescence to pharmaceutical analyses by using continuous-flow assemblies. A comprehensive study on the fundamentals of the chemiluminescence is also included.