High Relative Standard Deviation Research Articles

Simple distance-based thread analytical device integrated with ion imprinted polymer for Zn2+ quantification in human urine samples.

This article presents the development of a distance-based thread analytical device (dTAD) integrated with an ion-imprinted polymer (IIP) for quantitative monitoring of zinc ions (Zn2+) in human urine samples. The IIP was easily chemically modified onto the thread channel using dithizone (DTZ) as a ligand to bind to Zn2+ with methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as well as 2,2-azobisisobutyronitrile (AIBN) as cross-linking agents to enhance the selectivity for Zn2+ detection. The imprinted polymer was characterized using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS). Under optimization, the linear detection range was from 1.0 to 20.0 mg L-1 (R2 = 0.9992) with a limit of detection (LOD) of 1.0 mg L-1. Other potentially interfering metal ions and molecules did not interfere with this approach, leading to high selectivity. Furthermore, our technique exhibits a remarkable recovery ranging from 100.48% to 103.16%, with the highest relative standard deviation (% RSD) of 5.44% for monitoring Zn2+ in human control urine samples, indicating high accuracy and precision. Similarly, there is no significant statistical difference between the results obtained using our method and standards on zinc supplement sample labels. The proposed method offers several advantages in detecting trace Zn2+ for point-of-care (POC) medical diagnostics and environmental sample analysis, such as ease of use, instrument-free readout, and cost efficiency. Overall, our developed dTAD-based IIP method holds potential for simple, affordable, and rapid detection of Zn2+ levels and can be applied to other metal ions' analysis.

Development and Validation of the HPLC Method for Simultaneous Quantification of Glucose and Xylose in Sugar Cane Bagasse Extract.

A validated rapid high-performance liquid chromatography (HPLC)-refractive index (RI) method was developed for the identification and quantification of glucose and xylose in hydrolyzed bagasse extract. The separation of compounds was achieved on Eurokat® H column (300 × 8mm, 10μm) at 75°C, using 0.01N sulfuric acid solution as mobile phase and 0.6mL/min as flow rate. The method was validated based on accuracy, precision, linearity, robustness, uncertainty, limit of detection (LOD) and limit of quantification (LOQ). Total chromatographic analysis time per sample was ~11min. Calibration plots were linear over the concentration ranges 11-100μg/100μL for glucose and xylose. The LOD was 0.8ppm and LOQ was 2.5ppm. The high recovery and low relative standard deviation confirm the suitability of the method for determination of glucose and xylose in bagasse extract. The proposed HPLC-RI method was accurate, fast and robust and required less run time due to less analytes retention times and allowed optimal energy consumption owing to lower column oven temperature.

Distance-based paper analytical devices integrated with molecular imprinted polymers for Escherichia coli quantification.

Thedevelopment of distance-based paper analytical devices (dPADs) integrated with molecularly imprinted polymers (MIPs) to monitor Escherichia coli (E. coli) levels in food samplesis presented. The fluidic workflow on the device is controlled using a designed hydrophilic bridge valve. Dopamine serves as a monomer for the formation of the E. coli-selective MIP layer on the dPADs. The detection principle relies on the inhibition of the E. coli toward copper (II) (Cu2+)-triggered oxidation of o-phenylenediamine (OPD) on the paper substrate. Quantitative detection is simply determined through visual observation of the residual yellow color of the OPD in the detection zone, which is proportional to E. coli concentration. The sensing exhibits a linear range from 25.0 to 1200.0CFUmL-1 (R2 = 0.9992) and a detection limit (LOD) of 25.0CFUmL-1 for E. coli detection. Additionally, the technique is highly selective with no interference even from the molecules that have shown to react with OPD to form oxidized OPD. The developed device demonstrates accuracy and precision for E. coli quantification in food samples with recovery percentages between 98.3 and 104.7% and the highest relative standard deviation (RSD) of 4.55%. T-test validation shows no significant difference in E. coli concentration measured between our method and a commercial assay. The proposed dPAD sensor has the potential for selective and affordable E. coli determination in food samples without requiring sample preparation. Furthermore, this strategy can be extended to monitor other molecules for which MIP can be developed and integrated into paper-microfluidic platform.

Green synthesis of azo-linked porous organic polymer for enrichment of nitroimidazoles from water, shrimp and Basa fish

Reliable monitoring of nitroimidazoles (NDZs) is of great significance to public health. Herein, an azo-linked porous organic polymer (Res-POPs) was prepared by green synthesis method using natural resveratrol as monomer for the first time. Using Res-POPs as sorbent, a facile method coupling solid-phase extraction with high performance liquid chromatography-diode array detection was developed for effective detecting NDZs. The method achieved good linearities (0.06 ∼ 100 ng mL−1 for water, 1.8 ∼ 200 ng g−1 for shrimp, and 1.5 ∼ 200 ng g−1 for Basa fish) with determination coefficients above 0.995, low detection limits (0.02 ∼ 0.05 ng mL−1, 0.60 ∼ 1.00 ng g−1 and 0.50 ∼ 0.90 ng g−1 for water, shrimp and Basa fish), high method recovery (85 %∼114 %) and relative standard deviations below 8.2 %. The results demonstrated the superiority and the promising potential of the established method for detection of NDZs compared with the reported method.

Glyphosate detection via a nanomaterial-enhanced electrochemical molecularly imprinted polymer sensor

Glyphosate (GLY) is a widely used herbicide with an important role in agriculture. It effectively controls weeds, enhancing agricultural yield and product quality. However, its use raises significant concerns such as potential risks to non-target ecosystems and human health. In response to these concerns, we develop an electrochemical sensor with a molecularly imprinted polymer (MIP) and gold nanoparticles for GLY detection. The sensor includes a screen-printed carbon electrode (SPCE) functionalized with gold nanoparticles and a self-assembled polyvinyl carboxylic acid chloride (PVC-COOH) layer. GLY compounds interact with carboxylic groups and are encapsulated by a polymer of methacrylic acid (MAA) cross-linked with ethylene glycol dimethacrylate (EGDMA). Electrochemical performance was assessed using differential pulse voltammetry (DPV), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Morphological characterization was performed using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and atomic force microscopy (AFM). The sensor exhibits impressive selectivity, detecting GLY within a range of 273–1200 pg/mL with minimal interference from other pesticides. It boasts a low detection limit of 0.8 pg/mL (signal-to-noise ratio S/N = 3) by DPV and 0.001 pg/mL by EIS. The sensor’s versatility extends to various sample types, including surface water, agricultural wastewater, soil, and cucumber, demonstrating high recovery rates (> 96.05%) and low relative standard deviation (RSD) (< 5.7%). The developed MIP sensor is proven to be a valuable tool for rapid and highly sensitive detection of GLY in diverse environmental and agri-food samples.

Distance-based paper analytical device for multiplexed quantification of cytokine biomarkers using carbon dots integrated with molecularly imprinted polymer.

This article introduces distance-based paper analytical devices (dPADs) integrated with molecularly imprinted polymers (MIPs) and carbon dots (CDs) for simultaneous quantification of cytokine biomarkers, namely C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) in human biological samples for diagnosis of cytokine syndrome. Using fluorescent CDs and MIP technology, the dPAD exhibits high selectivity and sensitivity. Detection is based on fluorescence quenching of CDs achieved through the interaction of the target analytes with the MIP layer on the paper substrate. Quantitative analysis is easily accomplished by measuring the distance length of quenched fluorescence with a traditional ruler and naked eye readout enabling rapid diagnosis of cytokine syndrome and the underlying infection. Our sensor demonstrated linear ranges of 2.50-24.0 pg mL-1 (R2 = 0.9974), 0.25-3.20 pg mL-1 (R2 = 0.9985), and 1.50-16.0 pg mL-1 (R2 = 0.9966) with detection limits (LODs) of 2.50, 0.25, and 1.50 pg mL-1 for CRP, TNF-α, and IL-6, respectively. This sensor also demonstrated remarkable selectivity compared to a sensor employing a non-imprinted polymer (NIP), and precision with the highest relative standard deviation (RSD) of 5.14%. The sensor is more accessible compared to prior methods relying on expensive reagents and instruments and complex fabrication methods. Furthermore, the assay provided notable accuracy for monitoring these biomarkers in various human samples with recovery percentages ranging between 99.22% and 103.58%. By integrating microfluidic systems, nanosensing, and MIPs technology, our developed dPADs hold significant potential as a cost-effective and user-friendly analytical method for point-of-care diagnostics (POC) of cytokine-related disorders. This concept can be further extended to developing diagnostic devices for other biomarkers.

A new strategy for the determination of dinobuton fungicide by square wave stripping voltammetry on the multi-walled carbon nanotube electrode

Dinobuton is a fungicide with a dinitrophenol group pesticide, and its electrochemical behavior was investigated by cyclic voltammetry (CV) and square wave stripping voltammetry (SWSV) on a multi-walled carbon nanotube paste electrode (MWCNTPE). First of all, optimum parameters such as pH, step potential, frequency, puls amplitude, deposition time and, deposition potential were specified by using SWSV on the MWCNTPE. In the negative potential scans, two cathodic peaks appeared at nearly −480 mV and –760 mV due to the nitro groups on the molecule and the second sharp one appeared at −760 mV (versus Ag/AgCl) was used for analytical purposes. The linear working range was found to be within 3.74–25.8 μM on the MWCNTPE by SWSV in pH 7.0 Britton Robinson (BR) buffer solution. The limit of detection (LOD) and limit of quantification (LOQ) values were found to be 0.73 μM and 2.43 μM, respectively. The interference study was conducted in the presence of some pesticides such as triasulfuron, azinphos-methyl, bromoxynil-octanoate, dialifos, fipronil, vinclozolin, iprodione, procymidone, and some selected metal ions withal. Furthermore, the proposed method was also applied to apple juice, tap water, and grape juice, and percent recoveries (%) were detected as 105.9 ± 4.3; 98.3 ± 0.9; 103.7 ± 2.5% with relative standard deviations of 4.0, 1.0, and 2.4%, respectively. On the other hand, percent relative errors were calculated as 5.90, 1.65, and 3.74%, respectively. High recoveries and low relative standard deviations indicate that the applicability of the proposed method in both matrix and real samples is satisfying.

A highly sensitive micelle-enhanced synchronous spectrofluorimetric determination of the recently approved co-formulated drugs, bilastine and montelukast in pharmaceuticals and human plasma at nanogram levels.

In this study, the simultaneous determination of bilastine and montelukast, two recently approved co-formulated antihistaminic medications, was accomplished using a quick, sensitive, environmentally friendly, and reasonably priced synchronous fluorescence spectroscopic approach for the first time. Enhancement of the method's sensitivity down to nanogram levels was achieved by the addition of sodium dodecyl sulfate (1.0% w/v) as a micellar system. According to the results, bilastine and montelukast's fluorescence was measured at 255.3 and 355.3nm, respectively, using Δλ of 40.0nm and distilled water as a green diluting solvent. With respect to the concentration ranges of bilastine (5.0-300.0ng/ml) and montelukast (50.0-1000.0ng/ml), the method showed excellent linearity (r ≥ 0.9998). The results showed that the suggested method is highly sensitive, with detection limits of 1.42 and 13.74 ng/ml for bilastine and montelukast, respectively. Within-run precisions (intra- and interday) per cent relative standard deviations (RSD) for both analytes were <0.59%. With high percentage recoveries and low percentage RSD values, the designed approach was successfully applied for the simultaneous estimation of the cited medications in their dosage form and human plasma samples. To evaluate the green profile of the suggested method, an analytical GREENNESS metric approach (AGREE) and green analytical procedure index (GAPI) metric tools were used. These two methods for evaluating greenness confirmed that the developed method met the highest number of green requirements, recommending its use as a green substitute for the routine analysis of the studied drugs. The proposed approach was validated according to ICHQ2 (R1) guidelines.

Green Alternatives in Pharmaceutical and Bioanalytical Analysis of TDM Required Drugs: Procainamide.

In drug analysis, using non-hazardous solvents instead of the ones harmful to humans and the environment is a green strategy to protect analysts and environmental health. Procainamide (PCA) is an antiarrhythmic drug requiring therapeutic drug monitoring (TDM) because of its narrow therapeutic window and serious side effects. The aim of this study is to develop validated green HPLC methods to be used in drug quality control and TDM analysis for PCA, thus indicating the further applicability in the analysis of TDM-required drugs, such as immunosuppressants, anti-cancer drugs, and psychiatric drugs. Human-friendly ethanol was selected as an organic solvent in the mobile phase. PCA was eluted from NUCLEODUR 100-5 C8 ec (5 μm, 150 x 4.6 mm) column by a mobile phase containing ethanol and 50 mM NaH2PO4 buffer (5:95, v/v). The mobile phase flow rate was 1.0 ml min-1, the column temperature was 35 °C, and the wavelength at the PDA detector was 278 nm. Retention time for PCA was 5.0 min and 7.7 min for paracetamol as an internal standard (IS). In the green HPLC method for pharmaceutical analysis, the highest relative standard deviation (RSD) and mean recovery values were 1.32% and 98.89%, respectively. In the analysis of plasma, the sample preparation step was only smooth protein precipitation by ethanol. Thus, the bioanalytical method was fully green having a limit of detection (LOD) of 0.3 μg ml-1 and a limit of quantification (LOQ) of 0.8 μg ml-1. The therapeutic plasma concentration for PCA was reported in the range of 4-12 μg ml-1. As a result, the green HPLC methods developed and validated in this study were selective, accurate, precise, reproducible, and trustable and have the quality for the application in pharmaceutical and TDM analysis of PCA, thus encouraging green HPLC analysis of other TDM required drugs.

Laser–induced breakdown spectroscopy combined with surface coating to enhance emission line intensity of metallic elements in metal sheet

Emission intensity plays an important role in laser–induced breakdown spectroscopy. A new sample preparation method is proposed to enhance the emission intensity for determining metallic elements. A layer of epoxy resin film is cured on the surface of a metal sheet sample, and a laser beam is used to ablate the film and form a circular hole through it. Results show that by using the proposed method, the emission intensity for Al, Cr, Cu, Fe and W increases by 66.7%–699.6%, and the relative standard deviation (RSD) decreases from 6.5%–25.5% to 0.2%–12.9%. This suggests that emission lines with high intensity and low RSD can be obtained using the proposed method. This convenient and low–cost method has the potential for improving the quantification and imaging performance of bulk samples.

A portable smartphone-assisted Tb-MOF-based agar-slice probe for the rapid and on-site fluorescence assay of malachite green in aquatic products

In this study, a new Tb-MOF fluorescence probe was developed for the detection of malachite green (MG) in real aquatic products. Fluorescence sensing experiments revealed that MG can effectively quench the green fluorescence of Tb-MOF suspensions, and the detection process exhibits the advantages of high sensitivity, a wide linear range (0–80 μM), a low detection limit (10.8 nM) and a rapid response time. Selective detection of MG is achieved primarily through fluorescence resonance energy transfer (FRET) and photoinduced electron transfer (PET) mechanisms. Furthermore, a smartphone-assisted Tb-MOF-based agar slice detection platform was constructed for the visual and quantitative detection of MG. Additionally, the on-site detection of MG in crucian and shrimp samples was accomplished with high recoveries (99.8 %-107.99 %) and low relative standard deviations (RSD < 2.2 %). This developed detection platform introduced a low-cost, portable and user-friendly approach for MG detection.

Near blowout instabilities and identification based on multivariate analysis with high-speed multi-species optical diagnostic techniques

Early prediction and depth analysis of lean blowouts are desirable for both aeroengine and stationary gas turbines. This study used a combination of high-speed multi-species optical diagnostic techniques and multivariate analysis methods to investigate near-blowout instabilities and identify combustion conditions. The flame root dynamic behavior and heat release pulsation characteristics were investigated using advanced modal decomposition methods. Results showed that a near-blowout flame exhibited a characteristic frequency (∼200 Hz) or “fingerprint” related to the temporal and spatial coupling characteristics of CH and OH radicals. Furthermore, flame image feature screening and multivariate fusion for combustion condition identification are reported for the first time. Significant differential features and effective fusion models were investigated and discussed. The identification accuracy of the multivariate fusion feature model compared with that of the geometric feature model improved by more than 24 %. Moreover, simplified fusion models of low-order moment and geometric features were constructed with relatively high identification accuracy (99 %) and low relative standard deviation value (14.1 %). These results demonstrate the significant potential of combining multi-species optical diagnostic techniques and multivariate analysis methods, thereby expanding their application to the field of combustion science.

Two-in-one sensing platform for the detection of exosomes based on molybdenum disulfide-based nanozymes

Compared with single-mode detection strategies, multi-mode sensing strategies have attracted more and more scientists’ attention due to their higher detection accuracy and credibility. Herein, a two-in-one sensing platform was designed for human breast cancer cell line (MCF-7)-derived exosomes detection by coupling the high catalytic activity of gold-platinum core-shell nanoparticles-decorated molybdenum disulfide nanozymes (MoS2-Au@Pt) with the specific recognition ability of aptamers (Apt). Probe DNA1 (P1) was assembled on the surface of MoS2-Au@Pt nanozymes to form MoS2-based signal amplified nanoprobes (MNP), which can efficiently catalyze 3, 3′, 5, 5′-tetramethylbenzidine (TMB) and hydrogen peroxide (H2O2) reaction strategy to produce distinct electrochemical and colorimetric responses. The added target exosomes triggered the dissociation of the “probe DNA2-Apt-MNP” sandwiched structure and the release of MNP from the electrode surface due to the preferential reaction of anti-CD63 aptamer and exosomes, leading to both electrochemical signal and solution color were reduced. According to this interesting sensing principle, the developed electrochemical/colorimetric dual-mode aptasensor showed excellent sensitivity and specificity for exosomes analysis with low detection limits of 9.3 particles mL−1 (electrochemical) and 4.2 × 103 particles mL−1 (colorimetric), respectively. Furthermore, this dual-mode aptasensor can determine exosomes in human serum with high recoveries (>93 %) and low relative standard deviation (RSD, <8 %), suggesting that the developed dual-mode detection strategy is a promising sensing method for accurate, sensitive and selective analysis of biomarkers in clinical samples.

Method validation and monitoring of emamectin benzoate in mature banana fruit with peel and pulp through Liquid chromatography-Mass spectrometry/ Mass spectrometry (LC-MS/MS)

Emamectin benzoate has been frequently used in the banana ecosystem to combat the damage of pseudostem weevil. Therefore, the present study was conducted to validate the method, to assess harvest time residues and monitor emamectin benzoate residues in mature banana peel and pulp samples through LC-MS/MS. The validated method was used to determine emamectin benzoate residue in market banana samples. The study used Waters Alliance LC and Acquity TQD with an electrospray ionization interface in the positive ion mode. An isocratic flow of 0.1% formic acid (HCOOH) in water and 0.1% HCOOH in acetonitrile (CH3CN) was utilised for separation. CH3CN was utilised to extract emamectin benzoate residue from the samples, and a dispersive solid-phase extraction technique was used for subsequent cleanup. Linearity tests were performed with standard solutions containing 0.01 to 0.1 g mL-1, with three replicates for each concentration. For mature banana peel &amp; pulp and mature banana pulp matrices, satisfactory recoveries of 79.85 to 95.09% and 89.20 to 100.94%, respectively and high precision relative standard deviations of 0.56 to 2.34% and 2.33 to 6.88%, respectively were obtained. For mature banana (peel and pulp, pulp alone) fruits, the lower detection and quantification limits were (0.003, 0.008), and (0.002, 0.007). The validated approach was utilised to analyse mature banana fruit samples obtained from emamectin benzoate treated fields and banana samples purchased from the local market. Results showed satisfactory validation of parameters like linearity, the limit of detection and quantification, and recovery for determining emamectin benzoate residues in banana fruit.

Camellia oleifera derived carbon dots modified TiO2 as sensor for the rapid detection of 4-nitrophenol in wastewater

This paper presents an innovative electrochemical sensor utilizing carbon dots modified with titanium dioxide (TiO2-CDs) for the rapid and accurate detection of 4-nitrophenol (4-NP) in wastewater. This sensor offers a cost-effective and efficient approach to on-site monitoring of 4-NP, a highly toxic and persistent environmental pollutant. The modification of the electrode material with TiO2-CDs significantly enhances the sensor's performance by improving sensitivity, selectivity, and stability. The synthesis of TiO2-CDs involves the integration of carbon dots derived from biomass with TiO2, resulting in a composite material with an enlarged surface area and enhanced photocatalytic properties. The unique hollow spherical structure of the TiO2-CDs further amplifies their photon absorption capacity. Electrochemical characterization validates the successful modification of the electrode surface and demonstrates the electrocatalytic activity of the TiO2-CDs modified electrode towards 4-NP. The sensor exhibits a linear correlation between the peak oxidation current and the concentration of 4-NP, enabling precise and reliable quantification. Notably, the sensor's detection range spans from 10 μM to 350 μM, with an impressively low detection limit of 0.12 μM. Real sample analysis of wastewater underscores the sensor's practical utility, revealing high recovery rates and minimal relative standard deviations. The development of this electrochemical sensor, based on TiO2-CDs, presents a promising solution for the swift and accurate detection of 4-NP in wastewater, offering potential advancements in pollution control, environmental monitoring, and wastewater treatment strategies.

Highly Sensitive Photothermal Microfluidic Thread-Based Duplex Immunosensor for Point-of-Care Monitoring.

Herein, we successfully developed a thread-based analytical device (μTAD) for simultaneous immunosensing of two biomolecules with attomolar sensitivity by using a photothermal effect. A photothermal effect exploits a strong light-to-heat energy conversion of plasmonic metallic nanoparticles at localized surface plasmon resonance. The key innovation is to utilize the cotton thread to realize this sensor and the use of chitosan modification for enhancing the microfluidic properties, for improving the efficiency of photothermal conversion, and for sensor stability. The developed μTAD sensor consists of (i) a sample zone, (ii) a conjugation zone coated with gold nanoparticles bound with an antibody (AuNPs-Ab2), and (iii) a test zone immobilized with a capture antibody (anti-Ab1). The prepared μTAD is assembled in a custom three-dimensional (3D) printed device which holds the laser for illumination and the thermometer for readout. The 3D-printed supportive device enhances signal response by focusing light and localizing the heat generated. For proof of concept, simultaneous sensing of two key stress and inflammation biomarkers, namely, cortisol and interleukin-6 (IL-6), are monitored using this technique. Under optimization, this device exhibited a detection linear range of 2.0-14.0 ag/mL (R2 = 0.9988) and 30.0-360.0 fg/mL (R2 = 0.9942) with a detection limit (LOD) of 1.40 ag/mL (∼3.86 amol/L) and 20.0 fg/mL (∼950.0 amol/L) for cortisol and IL-6, respectively. Furthermore, the analysis of both biomolecules in human samples indicated recoveries in the range of 98.8%-102.88% with the highest relative standard deviation being 3.49%, offering great accuracy and precision. These results are the highest reported sensitivity for these analytes using an immunoassay method. Our PT-μTAD strategy is therefore a promising approach for detecting biomolecules in resource-limited point-of-care settings.

A powerful combination of liquid chromatography-triple quadrupole mass spectrometry and quadruple isotope dilution strategy for the determination of fenuron at trace levels in river water, stream water and fruit juice samples

An accurate, sensitive, and rapid analysis methodology for the determination of fenuron at ultratrace levels in river water, stream water and fruit juice samples was developed based on quadruple isotope dilution (ID4) and liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) system. Fenuron-d6 as isotopically labelled material (ILM) was synthesized in our laboratory to apply the ID4 method. Optimization studies were performed to find experimental conditions for the separation and detection of fenuron at trace levels. Analytical performance parameters such as limit of detection (LOD), limit of quantitation (LOQ) and linear range were determined by external calibration strategy. LOD and LOQ values for the analyte were found at ppt levels and a wide linear range was obtained in the range of 0.11 – 492.4 µg/kg. Recovery studies were also carried out for water and fruit juice samples to test applicability and accuracy of the developed LC-MS/MS system. ID4 strategy was applied to the selected samples to increase accuracy of the developed method and tolerate high matrix effects for fruit juice samples. According to high percent recoveries and low relative standard deviation values, the developed LC-ID4-MS/MS system was proven as an accurate, precise and sensitive analytical method for the quantification of fenuron at trace levels.

Development and validation of a high-performance liquid chromatography method for the estimation of esomeprazole in bulk and tablet dosage form

Introduction: An accurate, simple, precise, rapid, economic and reproducible reverse-phase high-performance liquid chromatography method was developed and validated for the estimation of Esomeprazole (ESO) in bulk and tablet dosage form. Method: The separation was carried out on Finepak SIL C18T-5 column (250 × 4.6 mm, 5.0 µm i. d.) using potassium dihydrogen phosphate buffer (0.025M): ACN (20:80 v/v) and at a flow rate of 1.0 mL/min. using UV detector at 302 nm with a run time of 10 min. The method was validated for accuracy for linearity, accuracy, precision, limit of detection (LOD), limit of quantification (LOQ) and robustness. Results: The standard calibration curve was linear with R2 = 0.995. LOD and LOQ obtained for esomeprazole were 0.0001 and 0.0004 µg/mL respectively. The method was found robust for possible changes. Results of analysis of other parameters were also tested and validated as per ICH guidelines and recovery studies confirmed the accuracy of the proposed method. validation studies showed that the developed HPLC method is simple, reproducible, rapid, precise and reliable. The high recovery and low relative standard deviation confirm the suitability of the developed method for the determination of esomeprazole in the tablet dosage form. Conclusion: This method may be used as a more convenient and efficient option for the analysis of esomeprazole to establish the quality of the substance during routine analysis with consistent and reproducible results.

Extraction method for the multiresidue analysis of legacy and emerging pollutants in marine mussels from the Adriatic Sea

The release of hazardous chemicals into aquatic environments has long been a known problem, but its full impact has only recently been realized. This study presents a validated liquid chromatography–mass spectrometry (HPLC–MS/MS) method for detecting pharmaceutical and pesticide residues in mussels (Mytilus galloprovincialis). An innovative MS-compatible extraction method was developed and validated, demonstrating successful recovery rates for analytes at three different concentration levels (25–95%). The method detected the target analytes at ng/g concentrations with high accuracy (−7% to 11%) and low relative standard deviation (<10%) for both intra-day and inter-day analyses. After validation, the method was applied to mussel samples collected from a commercial farm near Senigallia, Adriatic Sea, detecting different contaminants in the range of 2–40 ng/g (dry weight). The study provides a valuable tool for investigating the potential threats posed by diverse contaminant classes with high annual tonnage, including analytes with known persistence and/or illegal status.

Development and Validation of Stability Indicating RP-HPLC Method for the Estimation of Glycopyrrolate and Neostigmine in Bulk and Injection.

A stability indicating RP-HPLC method is suggested for determination of Glycopyrrolate-Neostigmine (GLY/NEO) in bulk drugs and injection formulation. GLY/NEO were eluted from a Chromolith High Resolution RP-18e (100 mm×4.6mm) with buffer solution (pH3.0) as mobile phase A and a mixture of HPLC grade acetonitrile and water mixture (90:10) as mobile phase B. The gradient was optimized with a flowrate of 0.5mL/min and wavelength of 222nm. A complete analytical method validation was effectively carried out as per ICH Q2 (R1) guidelines. Recovery studies were performed at 50-150% level of working concentrations, and results were in the range of 99-101%. The linearity was detected in the range of LOQ to 200% of the specification limits i.e., 0.5% each for NEO and GLY, 0.01% for NEO Impurity B and 1.0% for rest of the impurities with respect to the test concentration of the respective components. For stability study, various stress conditions such as acid, base, oxidation and thermal as per ICH guidelines were studied. The high recovery and low relative standard deviation confirm the suitability of proposed method that can be employed for the routine analysis in bulk and pharmaceutical formulation.