Capacitive sensor based on molecularly imprinted polymers for detection of the insecticide imidacloprid in water

This manuscript reports on the development of a capacitive sensor for the detection of imidacloprid (IMD) in water samples based on molecularly imprinted polymers (MIPs). MIPs used as recognition elements were synthesized via a photo-initiated emulsion polymerization. The particles were carefully washed using a methanol (MeOH) / acetic acid mixture to ensure complete template removal and were then dried. The average size of the obtained particles was less than 1 mu m. The imprinting factor (IF) for IMD was 6 and the selectivity factor (alpha) for acetamiprid, clothianidin, thiacloprid and thiamethoxam were 14.8, 6.8, 7.1 and 8.2, respectively. The particles were immobilized on the surface of a gold electrode by electropolymerization. The immobilized electrode could be spontaneously regenerated using a mixture of MeOH/10 mM of phosphate buffer (pH = 7.2)/triethylamine before each measurement and could be reused for 32 times. This is the first-time that automated regeneration was introduced as part of a sensing platform for IMD detection. The developed sensor was validated by the analysis of artificially spiked water samples. Under the optimal conditions, the linearity was in the range of 5-100 mu M, with a limit of detection (LOD) of 4.61 mu M

Green chromatographic method for analysis of some anti-cough drugs and their toxic impurities with comparison to conventional methods

Toxic solvents are widely used in chemical laboratories, which are dangerous on health, safety of workers, and environment. Green chemistry established different principles to keep safety of environment, one of these goals is to replace toxic solvents by greener alternatives or by minimizing the used volumes.Paracetamol (PAR), Guaifenesin (GUF), Oxomemazine (OX), and Sodium benzoate (SB) combination is a widely used cough preparation. 4- aminophenol (4-AP) is PAR poisonous impurity and related substance. Guiacol (GUC) is GUF impurity and related substance; its presence may lead to rejection of GUF sample.An eco-friendly HPTLC method was developed to quantify the studied drugs and their impurities. Chromatographic separation was achieved on HPTLC 60F254 plates using ethylacetate: methanol: 0.05 M ammonium chloride buffer (100: 2: 5, by volume) as a mobile phase and scanning at 225 nm. The linear ranges were 0.25–3.50, 0.50–8.00, 0.25–4.00, 0.20–8.00, 0.05–4.00, and 0.25–4.00 µg/band for PAR, GUF, OX and SB, 4-AP, and GUC. Method was successfully applied to available syrup and suppositories. It compared well with the reported method. It can be considered as an alternative green method for previously developed TLC method. Greenness profile of the method proved that it is greener than the reported methods being time and solvents saving. Keywords: Paracetamol, Guaifenesin, Oxomemazine, Sodium benzoate, 4-Aminophenol, Guiaco

Mean centering of ratio spectra and successive derivative ratio spectrophotometric methods for determination of isopropamide iodide, trifluoperazine hydrochloride and trifluoperazine oxidative degradate

Two sensitive, selective and precise stability indicating methods for the determination of isopropamide iodide (ISO), trifluoperazine hydrochloride (TPZ) and trifluoperazine oxidative degradate (DEG) were developed and validated. Method A is a successive derivative ratio spectrophotometric one, which depends on the successive derivative of ratio spectra in two steps using 0.1 N HCl as a solvent and measuring TPZ at 250.4 and 257.2 nm, ISO at 223 and 228 nm and DEG at 210.6, 213 and 270.2 nm. Method B is mean centering of ratio spectra which depends on using the mean centered ratio spectra in two successive steps and measuring the mean centered values of the second ratio spectra at 322, 355 and 339 nm for TPZ, ISO and DEG, respectively. Factors affecting the developed methods were studied and optimized, moreover, they have been validated as per ICH guidelines and the results demonstrated that the suggested methods are reliable, reproducible and suitable for routine use with short analysis time. Statistical analysis of the two developed methods with the reported one using F- and Student’s t-test showed no significant difference regarding accuracy and precision

Determination of Cefoperazone Sodium in Presence of Related Impurities by Linear Support Vector Regression and Partial Least Squares Chemometric Models

A comparison between partial least squares regression and support vector regression chemometric models is introduced in this study. The two models are implemented to analyze cefoperazone sodium in presence of its reported impurities, 7-aminocephalosporanic acid and 5-mercapto-1-methyl-tetrazole, in pure powders and in pharmaceutical formulations through processing UV spectroscopic data. For best results, a 3-factor 4-level experimental design was used, resulting in a training set of 16 mixtures containing different ratios of interfering moieties. For method validation, an independent test set consisting of 9 mixtures was used to test predictive ability of established models. The introduced results show the capability of the two proposed models to analyze cefoperazone in presence of its impurities 7-aminocephalosporanic acid and 5-mercapto-1-methyl-tetrazole with high trueness and selectivity (101.87 ± 0.708 and 101.43 ± 0.536 for PLSR and linear SVR, resp.). Analysis results of drug products were statistically compared to a reported HPLC method showing no significant difference in trueness and precision, indicating the capability of the suggested multivariate calibration models to be reliable and adequate for routine quality control analysis of drug product. SVR offers more accurate results with lower prediction error compared to PLSR model; however, PLSR is easy to handle and fast to optimize

Diosmin mitigates dexamethasone-induced osteoporosis in vivo: Role of Runx2, RANKL/OPG, and oxidative stress

Secondary osteoporosis is commonly caused by long-term intake of glucocorticoids (GCs), such as dexamethasone (DEX). Diosmin, a natural substance with potent antioxidant and anti-inflammatory properties, is clinically used for treating some vascular disorders. The current work targeted exploring the protective properties of diosmin to counteract DEX-induced osteoporosis in vivo. Rats were administered DEX (7 mg/kg) once weekly for 5 weeks, and in the second week, vehicle or diosmin (50 or 100 mg/kg/day) for the next four weeks. Femur bone tissues were collected and processed for histological and biochemical examinations. The study findings showed that diosmin alleviated the histological bone impairments caused by DEX. In addition, diosmin upregulated the expression of Runt-related transcription factor 2 (Runx2) and phosphorylated protein kinase B (p-AKT) and the mRNA transcripts of Wingless (Wnt) and osteocalcin. Furthermore, diosmin counteracted the rise in the mRNA levels of receptor activator of nuclear factor-kB ligand (RANKL) and the reduction in osteoprotegerin (OPG), both were induced by DEX. Diosmin restored the oxidant/antioxidant equilibrium and exerted significant antiapoptotic activity. The aforementioned effects were more pronounced at the dose level of 100 mg/kg. Collectively, diosmin has proven to protect rats against DEX-induced osteoporosis by augmenting osteoblast and bone development while hindering osteoclast and bone resorption. Our findings could be used as a stand for recommending supplementation of diosmin for patients chronically using GCs

Development and Validation of Ecofriendly HPLC-MS Method for Quantitative Assay of Amoxicillin, Dicloxacillin, and Their Official Impurity in Pure and Dosage Forms

Novel, accurate, selective, and rapid high-performance liquid chromatography mass spectrometry method was developed for simultaneous analysis of amoxicillin trihydrate, dicloxacillin sodium, and their official impurity 6-aminopenicillanic acid. The chromatographic separation was carried out by applying the mixture on a C18 column (3.5 µm ps, 100 mm × 4.6 mm id) using acetonitrile:water (65 : 35 by volume) as a mobile phase within only 4 min. The quantitative analysis was executed using single quadrupole mass spectrometer in which electrospray ionization, selected ion monitoring, and negative mode were operated. The retention times were 1.61, 2.54, and 3.50 mins for amoxicillin, 6-aminopenicillanic acid, and dicloxacillin, respectively. The method was validated in linear ranges of 2–28 µg mL−1, 2–35 µg mL−1, and 1–10 µg mL−1 for amoxicillin, dicloxacillin, and 6-aminopenicillanic acid, respectively. The results obtained from the suggested HPLC/MS were statistically compared with those obtained from the reported HPLC method, where no significant difference appeared respecting accuracy and precision. According to the analytical eco-scale assessment method, the proposed method was proved to be greener than the reported one, where the analysis time and the amount of the wasted effluent decreased

3D bismuth ferrite nanoflowers electrochemical sensor for the multiple detection of pesticides

Food and environmental safety are a worldwide challenge to human health. Continuous monitoring of food and environmental contaminants through the development of novel and sensitive analytical techniques is a must. Among these contaminants are pesticides which are broadly used by farmers to control crop diseases. These chemicals and their metabolites are usually accumulating in plant tissues and in water which eventually will have negative public health effects on consumers. The detection of these contaminants mainly depends on separation technologies such as liquid or gas chromatography coupled with a mass spectrometer or an immunological interaction such as in enzyme-linked immunosorbent assays. Despite being sensitive and specific, all these techniques require the use of expensive equipment and highly trained personnel which limit their applications in many countries with poor equipped facilities and specialists. To cope with this obstacle, nanomaterials-based biosensors have been proposed as rapid, sensitive, efficient and portable alternatives to the traditional detection techniques. Therefore, in this work we present for the first time a novel electrochemical sensor based on a carbon paste electrode (CPE) modified with bismuth ferrite nanoparticles (BiFeO3/CPE) to detect two of the most commonly used pesticides in agriculture worldwide (imidacloprid “IMD” and fipronil “FIP”). IMD was introduced to the market in 1992 as a first member of the neonicotinoids class (neonics). Neonics and FIP applications in seed and soil represent around 60% of pesticides worldwide. Moreover, IMD usage accounts for 41.5% of the whole neonics market. IMD and FIP were found to be toxic to sensitive aquatic invertebrates at very low concentrations (<100 ng/L). Their chemical properties in addition to their impact on pollinators (honeybees and bumble bees) have raised an EU concern. Therefore, monitoring of both analytes in water is essential to reduce their negative impacts on health and environment. The modified- CPE showed a synergetic effect towards the oxidation of IMD and FIP. The prepared nanoparticles were investigated and characterized using SEM, TEM, XRD and FT-IR. The described voltammetric technique was optimized and validated. Under the optimal conditions, the sensor showed a sensitive response to their determination over a linear range (1 μM – 100 μM) in water. The detection limits (LODs) for IMD and FIP were determined as 0.97 μM and 1.27 μM, respectively. The recovery percentages for IMD and FIP in environmental water samples varied from 90 %-105 %. In conclusion, the developed sensor was successfully optimized and can be used for the simultaneous detection of both IMD and FIP in environmental water samples