Recent applications of flow-injection and sequential-injection analysis techniques to chemiluminescence determination of pharmaceuticals

Transparent Cross-Flow Platform as Chemiluminescence Detection Cell in Cross Injection Analysis

This work presents the use of a transparent 'Cross Injection Analysis' (CIA) platform as a flow system for chemiluminescence (CL) measurements. The CL-CIA flow device incorporates introduction channels for samples and reagents, and the reaction and detection channels are in one acrylic unit. A photomultiplier tube placed above the reaction channel detects the emitted luminescence. The system was applied to the analysis of (i) Co(II) via the Co(II)-catalyzed H₂O₂-luminol reaction and (ii) paracetamol via its inhibitory effect on the catalytic activity of Fe(CN)₆^3- on the H₂O₂-luminol reaction. A linear calibration was obtained for Co(II) in the range of 0.002 to 0.025 mg L^-1 Co(II) (r² = 0.9977) for the determination of Co(II) in water samples. The linear calibration obtained for the paracetamol was 10 to 200 mg L^-1 (r² = 0.9906) for the determination of pharmaceutical products. The sample throughput was 60 samples h^-1. The precision was ≤4.2% RSD. The consumption of the samples and reagents was ca. 170 µL per analysis cycle.

Real-time monitoring of Metridia luciferase release from cells upon interaction with model toxic substances by a fully automatic flow setup - A proof of concept

This manuscript reports on a fully automatic sequential injection system incorporating a 3D printed module for real-time monitoring of the release of Metridia luciferase from a modified liver epithelial cell line. To this end, a simple and effective approach for the automation of flash-type chemiluminescence assays was developed. The 3D printed module comprised an apical and a basal compartment that enabled monitoring membrane processes on both sides of the cell monolayer aimed at elucidating the direction of luciferase release. A natural release was observed after transfection with the luciferase plasmid by online measurement of the elicited light from the reaction of the synthesized luciferase with the coelenterazine substrate. Model substances for acute toxicity from the group of cholic acids - chenodeoxycholic and deoxycholic acids - were applied at the 1.0 and 0.5 mmol L^-1 levels. The tested cholic acids caused changes in cell membrane permeability that was accompanied by an increased luciferase release. The obtained kinetic profiles were evaluated based on the delay between the addition of the toxic substance and the increase of the chemiluminescence signal. All experiments were carried out in a fully automatic system in ca. 5 min per sample in 30 min intervals and no manual interventions were needed for a sampling period of at least 6 h.

Chemical Derivatization in Flow Analysis

Chemical derivatization for improving selectivity and/or sensitivity is a common practice in analytical chemistry. It is particularly attractive in flow analysis in view of its highly reproducible reagent addition(s) and controlled timing. Then, measurements without attaining the steady state, kinetic discrimination, exploitation of unstable reagents and/or products, as well as strategies compliant with Green Analytical Chemistry, have been efficiently exploited. Flow-based chemical derivatization has been accomplished by different approaches, most involving flow and manifold programming. Solid-phase reagents, novel strategies for sample insertion and reagent addition, as well as to increase sample residence time have been also exploited. However, the required alterations in flow rates and/or manifold geometry may lead to spurious signals (e.g., Schlieren effect) resulting in distorted peaks and a noisy/drifty baseline. These anomalies can be circumvented by a proper flow system design. In this review, these aspects are critically discussed mostly in relation to spectrophotometric and luminometric detection.

Flow Injection Techniques for Tetracycline Quantification: A Review

The multiple therapeutic potentials of tetracycline and its worldwide usage have encouraged researchers to develop various methods for its assay in various matrices and for different purposes. In this regard, different analytical techniques have been exploited. Among those techniques is flow injection (FI), which is an extended family of three generations and five versions. The current manuscript reviews the utilization of FI techniques for developing assay methods for tetracycline. The review covers more than forty methods, since the inception of FI techniques and up to date. The review highlights the advantages of the application of FI techniques for quantification of tetracycline in terms of reagent consumption, sample frequency, accuracy, and practitioner safety, besides instrumentation simplicity and cost-effectiveness. The review also addresses applications to several matrices ranging from simple matrices such as standard solutions and pharmaceutical formulations to complex matrices such as biological fluids and food. Prior to the review, a brief background on the principles and developments of FI techniques is illustrated.

Development of a Handheld Submersible Chemiluminescent Sensor: Quantification of Superoxide at Coral Surfaces

Reactive oxygen species (ROS) are produced via various photochemical, abiotic, and biological pathways. The low concentration and short lifetime of the ROS superoxide (O₂^•-) make it challenging to measure in natural systems. Here, we designed, developed, and validated a DIver-operated Submersible Chemiluminescent sensOr (DISCO), the first handheld submersible chemiluminescent sensor. The fluidic system inside DISCO is controlled by two high-precision pumps that introduce sample water and analytical reagents into a mixing cell. The resultant chemiluminescent signal is quantified by a photomultiplier tube, recorded by a miniature onboard computer and monitored in real time via a handheld underwater LED interface. Components are contained within a pressure-bearing housing (max depth 30 m), and an external battery pack supplies power. Laboratory calibrations with filtered seawater verified instrument stability and precision. Field deployment in Cuban coral reefs quantified background seawater-normalized extracellular superoxide concentrations near coral surfaces (0-173 nM) that varied distinctly with coral species. Observations were consistent with previous similar measurements from aquaria and shallow reefs using a standard benchtop system. In situ quantification of superoxide associated with corals was enabled by DISCO, demonstrating the potential application to other shallow water ecosystems and chemical species.

A molecularly imprinted polymer based chemiluminescence array sensor for one-step determination of phenothiazines and benzodiazepines in pig urine

The residues of phenothiazines and benzodiazepines in foods of animal origin are dangerous to consumers. For inspection of their abuses, this study for the first time reported on the use of a chemiluminescence array sensor for the simultaneous determination of four phenothiazines and five benzodiazepines in pig urine. Two molecularly imprinted polymers were coated in different wells of a conventional 96-well microtiter plate as the recognition reagents. After sample loading, the absorbed analytes were initiated directly by using an imidazole enhanced bis(2,4,6-trichlorophenyl)oxalate-hydrogen peroxide system to emit light. The assay process consisted of only one sample-loading step prior to data acquisition, so one test was finished within 10 min. The limits of detection for the nine drugs in the pig urine were in a range of 0.1 to 0.6 pg/mL, and the recoveries from the fortified blank urine samples were in a range of 80.3 to 95%. Furthermore, the sensor could be reused six times. Therefore, this sensor could be used as a simple, rapid, sensitive and reusable tool for routine screening for residues of phenothiazines and benzodiazepines in pig urine.

Flow analysis with chemiluminescence detection: Recent advances and applications

This article highlights the most important developments in flow analysis with chemiluminescence (CL) detection, describing different flow systems that are compatible with CL detection, detector designs, commonly applied CL reactions and approaches to sample treatment. Recent applications of flow analysis with CL detection (focusing on outputs published since 2010) are also presented. Applications are classified by sample matrix, covering foods and beverages, environmental matrices, pharmaceuticals and biological fluids. Comprehensive tables are provided for each area, listing the specific sample matrix, CL reaction used, linear range, limit of detection and sample treatment for each analyte. Finally, recent and emerging trends in the field are also discussed.

A Flow Method for Chemiluminescence Determination of Antimony(III) and Antimony(V) Using a Rhodamine B-Cetyltrimethylammonium Chloride Reversed Micelle System Following On-Line Extraction

A rapid and sensitive flow method, based on the combination of on-line solvent extraction with reversed micellar mediated chemiluminescence (CL) detection using rhodamine B (RB), was developed for the determination of antimony(III) and antimony(V) in aqueous samples. The on-line extraction procedure involved ion-pair formation of the antimony(V) chloro-complex anion with the protonated RBH(+) ion and its extraction from an aqueous hydrochloric acid solution into toluene, followed by phase separation using a microporous membrane. When in a flow cell of a detector, the ion-pair in the extract driven was mixed with the reversed micellar solution of cetyltrimethylammonium chloride in 1-hexanol-cyclohexane/water (0.60 mol dm(-3) H2SO4) containing cerium(IV), its uptake by the reversed micelles and the subsequent CL oxidation of RB with Ce(IV) occurred easily, then the produced CL signal was measured. Using the proposed flow method under the optimized experimental conditions, a detection limit (DL) of 0.35 μmol dm(-3) and a linear calibration graph with a dynamic range from DL to 16 μmol dm(-3) were obtained for Sb(V) with a precision of 1.4% relative standard deviation (n = 5) at the Sb(V) concentration of 8.2 μmol dm(-3). The present method was successfully applied to the determination of Sb(V) in water samples and to the differential determination of Sb(III) and Sb(V) in copper electrolyte industrial samples, where total antimony Sb(III) + Sb(V) was determined after oxidation of Sb(III) to Sb(V) with Ce(IV) and Sb(III) was calculated by difference, for which the DL was almost the same as that for Sb(V).

Recent advances in flow injection analysis

A dynamic development of methodologies of analytical flow injection measurements during four decades since their invention has reinforced the solid position of flow analysis in the arsenal of techniques and instrumentation of contemporary chemical analysis.

Gold nanoclusters-based chemiluminescence resonance energy transfer method for sensitive and label-free detection of trypsin

A chemiluminescence resonance energy transfer (CRET) platform was developed for sensitive and label-free detection of protease by using trypsin as a model analyte. In this CRET platform, bis(2,4,6-trichlorophenyl)oxalate-hydrogen peroxide chemiluminescence (CL) reaction was utilized as an energy donor and bovine serum albumin (BSA)-stabilized gold nanoclusters (Au NCs) as an energy acceptor. The BSA-stabilized Au NCs triggered the CRET phenomenon by accepting the energy from TCPO-H2O2 CL reaction, thus producing intense CL. In the presence of trypsin, the protein template of BSA-stabilized Au NCs was digested, which frustrated the energy transfer efficiency between the CL donor and the BSA-stabilized Au NCs, leading to a significant decrease in the CL signal. The decreased CL signal was proportional to the logarithm of trypsin concentration in the range of 0.01-50.0µg mL(-1). The detection limit for trypsin was 9ng mL(-)(1) and the relative standard deviations were lesser than 3% (n=11). This Au NCs-based CRET platform was successfully applied to the determination of trypsin in human urine samples, demonstrating its potential application in clinical diagnosis.

Simultaneous determination of iron (II) and ascorbic acid in pharmaceuticas based on flow sandwich technique

The simple and easy performed flow system based on sandwich technique has been developed for the simultaneous separate determination of iron (II) and ascorbic acid in pharmaceuticals. The implementation of sandwich technique assumed the injection of sample solution between two selective reagents and allowed the carrying out in reaction coil two chemical reactions simultaneously: iron (II) with 1,10-phenanthroline and ascorbic acid with sodium 2,6-dichlorophenolindophenol. For achieving of excellent repeatability and considerable reagent saving the various parameters such as flow rate, sample and reagent volumes, reaction coil length were also optimized. The limits of detection (LODs) obtained by using the developed flow sandwich-type approach were 0.2 mg L(-1) for iron (II) and 0.7 mg L(-1) for ascorbic acid. The suggested approach was validated according to the following parameters: linearity and sensitivity, precision, recoveries and accuracy. The sampling frequency was 41 h(-1).

Electrochemical biotin detection based on magnetic beads and a new magnetic flow cell for screen printed electrode

The use of the first flow-cell for magnetic assays with an integrated magnet is reported here. The flow injection analysis system (FIA) is used for biotin determination. The reaction scheme is based on a one step competitive assay between free biotin and biotin labeled with horseradish peroxidase (B-HRP). The mixture of magnetic beads modified with streptavidin (Strep-MB), biotin and B-HRP is left 15 min under stirring and then a washing step is performed. After that, 100 μL of the mixture is injected and after 30s 100 μL of 3,3',5,5'-Tetramethylbenzidine (TMB) is injected and the FIAgram is recorded applying a potential of -0.2V. The linear range obtained is from 0.01 to 1 nM of biotin and the sensitivity is 758 nA/nM. The modification and cleaning of the electrode are performed in an easy way due to the internal magnet of the flow cell.

Potassium permanganate-acridine yellow chemiluminescence system for the determination of fluvoxamine, isoniazid and ceftriaxone

Based on the oxidation of acridine yellow by permanganate in basic medium, a new chemiluminescence system was developed for the sensitive determination of some important drugs. The remarkable inhibiting effect of fluvoxamine, ceftriaxone and isoniazid on this reaction was applied to their detection. A possible mechanism was proposed for this system based on chemiluminescence emission wavelengths and experimental observations. Under optimum conditions, calibration graphs were obtained for 1 × 10(-9) to 1 × 10(-6) mol/L of fluvoxamine; 2 × 10(-8) to 8 × 10(-6) mol/L of ceftriaxone and 5 × 10(-8) to 4 × 10(-5) mol/L of isoniazid. This proposed method was satisfactorily used in the determination of these drugs in pharmaceutical samples and human urine and serum.

An ultrasensitive chemiluminescent method for the tanshinol borneol ester determination and its pharmacokinetic analysis

Tanshinol borneol ester (DBZ), a chemical combination of danshensu and borneol, is an experimental drug that exhibits efficacious anti-ischemic activity in animal models. In this work, an ultrasensitive chemiluminescence (CL) method for the determination of DBZ was established based on the inhibitory effect of DBZ on the CL signal produced from the reaction between potassium permanganate and luminol in alkaline solution. The CL intensity responded linearly to the concentration of DBZ in the range 2.0 × 10(-10) to 4.0 × 10(-8) g/mL with a detection limit of 7 × 10(-11) g/mL. The relative standard deviation (RSD) was 3.8% for 4.0 × 10(-9) g DBZ (n = 11). The proposed method showed characteristics of high sensitivity, simple device and quick. In addition, this proposed method had been applied satisfactorily to the analysis of DBZ in blood. The pharmacokinetics of DBZ in rat has also been studied using the CL method.

Microplate analytical method for quinones by pulse photo-irradiation and chemiluminescence detection

Quinones are widely distributed in nature and have various bioactivities. Besides, quinones are also considered as toxicological intermediates which cause severe dangerous effects. Hereby, a sensitive, simple, and rapid method is reported for quinones determination. The proposed method employed time resolved fluorescence (TRF) microplate reader based chemiluminescent (CL) detection for the first time as a novel approach for measurement. Under pulse photo-irradiation, the unique photochemical characteristic of quinones is exploited to liberate reactive oxygen species (ROS) which reacted with photosensitized CL reagent. L-012, luminol analogue, was selected for its high sensitivity. Under our investigation, para-quinones showed high CL response when compared to ortho-quinones. A linear response was obtained for studied quinone concentrations in the range of 0.05-50 μM for 1,4-naphthquinone and of 0.05-150 μM for 2-methyl-1,4-naphthoquinone (menadione) and 9,10-anthraquinone with detection limit (blank + 3SD) of 0.01 μM. The proposed method allowed the rapid determination of large number of samples in very short time (96 sample/125 s). The proposed method was successfully applied for determination of menadione in spiked human serum.

Flow-based systems for rapid and high-precision enzyme kinetics studies

Enzyme kinetics studies normally focus on the initial rate of enzymatic reaction. However, the manual operation of steps of the conventional enzyme kinetics method has some drawbacks. Errors can result from the imprecise time control and time necessary for manual changing the reaction cuvettes into and out of the detector. By using the automatic flow-based analytical systems, enzyme kinetics studies can be carried out at real-time initial rate avoiding the potential errors inherent in manual operation. Flow-based systems have been developed to provide rapid, low-volume, and high-precision analyses that effectively replace the many tedious and high volume requirements of conventional wet chemistry analyses. This article presents various arrangements of flow-based techniques and their potential use in future enzyme kinetics applications.

Determination of melamine by flow injection analysis based on chemiluminescence system

In this paper, based upon the phenomenon that melamine can obviously enhance the CL signal of the luminol-H(2)O(2) system in basic medium, a simple, rapid and sensitive flow injection chemiluminescence (FI-CL) method for the determination of melamine has been developed. Under the optimum conditions, the linear range for the determination of melamine was 0.2-80μgmL(-1) with a detection limit of 0.12μgmL(-1) calculated as proposed by IUPAC and a relative standard deviation of 3.26% for 11 solutions of 10μgmL(-1) melamine on the same day. The proposed method was satisfactorily applied to determine melamine in milk-based products and satisfactory results were obtained without interferences from the sample matrix. Moreover, one assay produce takes only 25s and the minimum sampling rate is about 120 samplesh(-1), which indicated that the FI-CL method was suitable for high throughput and real-time melamine analysis.

Development of a multicommutated flow system with chemiluminometric detection for quantification of gentamicin in pharmaceuticals

A new flow procedure based on multicommutation with chemiluminometric detection was developed to quantify gentamicin sulphate in pharmaceutical formulations. This approach is based on gentamicin's ability to inhibit the chemiluminometric reaction between luminol and hypochlorite in alkaline medium, causing a decrease in the analytical signal. The inhibition of the analytical signal is proportional to the concentration of gentamicin sulphate, within a linear range of 1 to 4 μg mL(-1) with a coefficient variation <3%. A sample throughput of 55 samples h(-1) was obtained. The developed method is sensitive, simple, with low reagent consumption, reproducible, and inexpensive, and when applied to the analysis of pharmaceutical formulations (eye drops and injections) it gave results with RSD between 1.10 and 4.40%.