Simultaneous chemiluminescence determination of amoxicillin and clavulanic acid using least squares support vector regression

Development and validation of a high-performance thin layer chromatography method for the simultaneous determination of amoxicillin and clavulanic acid combinations in tablet dosage forms

A simple and sensitive high-performance thin layer chromatography (HPTLC) method was developed and validated as per the International Council for Harmonization (ICH) guidelines for the simultaneous determination of amoxicillin (AMX) and clavulanic acid (CLA) combinations in tablet formulations. Chromatography was performed on precoated glass plates with normal phase silica gel 60 F254. The mobile phase was acetone:ethyl acetate:glacial acetic acid:water (11:9:4:2 (v/v)). The plate was scanned at a wavelength of 428 nm after derivatization with ninhydrin. The validation of the method revealed that the linearity range lies between 400 and 1200 ng/band for AMX and 100-300 ng/band for CLA, with coefficients of determination of 0.9997 and 0.9966, respectively. Recoveries in standard addition accuracy studies were 100.3 % for AMX and 96.75 % for CLA. The limit of detection (LOD) and limit of quantitation (LOQ) of the developed method are 20.3 ng/band and 61.6 ng/band for AMX and 18.5 ng/band and 56.2 ng/band for CLA, respectively. The new, novel high-performance thin layer chromatography (HPTLC) method that was successfully developed in this study was applied for the simultaneous determination of AMX and CLA in their fixed-dose tablet dosage forms obtained from retail pharmacies and offered comparable results with the official British Pharmacopoeial high-performance liquid chromatography (HPLC) method.

A molecularly imprinted electrochemical aptasensor based on zinc oxide and co-deposited gold nanoparticles/reduced graphene oxide composite for detection of amoxicillin

The molecularly imprinted electrochemical aptasensor was constructed based on co-deposition of zinc oxide and gold nanoparticles/reduced graphene oxide composite. Aptamer was used as a new kind of functional monomer and the aptamer-amoxicillin complex was formed by hydrogen bond. Then, the complex was fixed on the surface of the modified electrode by Au-S bond. Three-dimensional imprinted polymeric membrane was formed by electropolymerization of dopamine, and the imprinted sites with good specificity and affinity were formed after elution. Combined with the specificity of molecularly imprinted technology and the affinity of aptamer, the selective recognition of amoxicillin can be realized. Under the optimal experimental conditions, the linear range was from 10^-14 to 10^-8 M, and the detection limit was 3.3 × 10^-15 M. The sensor exhibited satisfactory selectivity, repeatability, and stability and was successfully used for 10^-9 M amoxicillin determination in real water and food samples.

Double-signal quantification of amoxicillin based on interaction with 4-aminoantipyrine at copper and nitrogen co-doped carbon quantum dots as an artificial nanozyme

An one-pot hydrothermal method was developed for synthesis of carbon quantum dots co-doped with copper and nitrogen (Cu, N@CQDs). The synthesized Cu, N@CQDs has unique advantages such as high fluorescence quantum yield (39.1%) and high catalytic activity. Oxidative coupling of amoxicillin (AMX) with 4-aminoantipyrine (4-NH₂-APE) in the presence of H₂O₂ as an oxidant to produce pink quinoneimine chromogen was carried out with the aid of Cu, N@CQDs as a peroxidase-like catalyst. This system was used for the colorimetric and fluorometric assays of AMX with reliable results. Colorimetric method is based on the measurement of a pink-colored product at λ_max = 505 nm while the fluorometric assay is based on the quenching of the fluorescence emission of Cu, N@CQDs at 440 nm after excitation at 370 nm. For the colorimetric method, the absorption intensity linearly increased over the concentration range 4.3-110.0 µM with LOD (S/N = 3) of 1.3 µM. For the fluorometric method, the emission intensity of Cu, N@CQDs linearly decreased upon addition of AMX in the concentration range 0.2-120.0 µM with a limit of detection (LOD, S/N = 3) of 0.06 µM. The proposed system was applied to the determination of AMX in different real samples such as pharmaceutical capsules, human serum, milk, and conduit water samples with recoveries in the range 95.8-104.1% and relative standard deviation (RSD %) less than 4.1%.

Design a fluorometric aptasensor based on CoOOH nanosheets and carbon dots for simultaneous detection of lysozyme and adenosine triphosphate

Simultaneous detection of biomarkers and biomolecules with great analytical performance still is challenging. A simple fluorometric dual-functional aptasensor was designed to detect Lysozyme (LYS) and adenosine triphosphate (ATP) as models of a protein and a small molecule simultaneously. The sensing principle of the aptasensor is based on the interactions between cobalt oxyhydroxide CoOOH nanosheets as fluorescence quencher and carbon dots (CDs) as fluorophores. The aptamer labeled with CDs was able to assemble on CoOOH nanosheets and consequently, the fluorescence signal was quenched. With addition target analytes to the system, the aptamers folded around of targets with a strong and specific affinity. Therefore, the labeled aptamer with CDs was detached from CoOOH nanosheets and the fluorescence signal was restored. The fluorescence spectral overlap of these two CDs is the main limitation for the simultaneous analysis. The least squared support vector machine (LS-SVM) was applied to resolve this problem. Under optimal conditions, when LS-SVR was used, detection limits were found 4.0 and 1.8 nmol L^-1 for ATP and LYS. The parallel biosensor is capable of monitoring ATP and LYS levels in the biological samples with satisfactory results.

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.

The analytical determination and electrochemiluminescence behavior of amoxicillin

A novel electrochemiluminescence (ECL) luminophor of amoxicillin was studied and found to generate ECL following the oxidation or reduction of amoxicillin. The amoxicillin oxidation state was also found to eliminate the reduction state, generating ECL. When solutions of amoxicillin were scanned between +1.5 V and -1.0 V with a graphite electrode in the presence of cetyltrimethyl ammonium bromide using KC1 as the supporting electrolyte, ECL emissions were observed at potentials of -0.7 V and +0.5 V. The ECL intensity at -0.7 V was enhanced by H2O2. Based on these findings, an ECL method for the determination of the amoxicillin concentration is proposed. The ECL intensities were linear with amoxicillin concentrations in the range of 1.8 × 10-8 g/mL to 2.5 × 10-7 g/mL, and the limit of detection (signal/noise = 3) was 5 × 10-9 g/mL. The florescence of amoxicillin had the greatest emission intensity in a neutral medium, with the emission wavelength dependent on the excitation wavelength. The experiments on the ECL mechanism for amoxicillin found that the electrochemical oxidation products of dissolved oxygen and active oxygen species contributed to the ECL process. The data also suggest that the hydroxyl group of amoxicillin contributed to its ECL emission.

Highly sensitive colorimetric determination of amoxicillin in pharmaceutical formulations based on induced aggregation of gold nanoparticles

A novel, simple and highly sensitive colorimetric method is developed for determination of Amoxicillin (AMX). The system is based on aggregation of citrate-capped gold nanoparticles (AuNP) in acetate buffer (pH=4.5) in the presence of the degradation product of Amoxicillin (DPAMX). It was found that the color of gold nanoparticles changed from red to purple and the intensity of surface plasmon resonance (SPR) peak of AuNPs decreased. A new absorption band was appeared in the wavelength range of 600-700nm upon addition of DPAMX. The absorbance ratio at the wavelength of 660 and 525nm (A660/A525) was chosen as the analytical signal indirectly related to AMX concentration. The linearity of the calibration graph was found over the concentration range of 0.3-4.5μM AMX with a correlation coefficient of 0.9967. Under the optimum experimental conditions, the detection limit was found to be 0.15μM. The applicability of the method was successfully demonstrated by analysis of AMX in pharmaceutical formulations including capsules and oral suspensions.

Simultaneous chemiluminescence determination of citric acid and oxalic acid using multi-way partial least squares regression

A novel kinetic chemiluminescent method proposed for the simultaneous determination of oxalic acid and citric acid in their mixtures.