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

Serum level of Adrenomedullin in patients with primary knee osteoarthritis; relation to disease severity

Abstract Background Adrenomedullin (AM) is a peptide which was suggested to be involved in the pathogenesis of osteoarthritis through its anti-inflammatory and anti-apoptotic effect. AM was found to be elevated in some inflammatory rheumatic diseases as rheumatoid arthritis and ankylosing spondylitis. The current study was performed to measure serum Adrenomodullin (AM) concentrations in patients with primary knee osteoarthritis (KOA) and to assess association with severity of the disease. The study was performed on 50 patients with primary KOA diagnosed according to American College of Rheumatology (ACR) Revised Criteria for Early Diagnosis of Knee Osteoarthritis and 20 age- and sex-matched controls with no clinical features of KOA. The Kellgren and Lawrence (KL) classification was used to evaluate the disease severity of knee OA. Disease activity was assessed by The Western Ontario and McMaster Universities Arthritis Index (WOMAC). Blood samples had been collected from patients with OA and controls for assessing Adrenomodullin in patients’ sera by ELISA. Results There were a significant increase in serum Adrenomedullin concentrations in KOA patients compared to controls (10.64 ±19.2 ng/ml vs. 1.39 ±1.6 ng/ml in cases and controls respectively) (p value = 0.036). There was positive significant correlation of serum Adrenomedullin levels with KL grades (r=0.608, p value 6 have significantly higher serum Adrenomedullin levels than OA patients with VAS Score 0.05). Conclusion This study concluded that serum Adrenomedullin (AM) level is elevated in patients with KOA and is positively correlated with the severity of disease

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

3D Bismuth ferrite microflowers electrochemical sensor for the multiple detection of pesticides

A plethora of scientific researches has constantly studied the electrochemical detection of different pesticides due to their serious effects on humans. Imidacloprid (IMD) is a pesticide that belongs to the neonicotinoids group. In the current work, a carbon paste electrode (CPE) modified with bismuth ferrite microflowers (BiFeO3/CPE) was used for sensing of IMD in water samples in the presence of fipronil (FIP). The modifier (BiFeO3) was characterized by different techniques. To evaluate the efficiency of the developed electrode towards the detection of both IMD and FIP in water samples, the square wave voltammetry (SWV) technique was employed and spiked water samples were used. The calibration curves were within the range of 1.0-100.0 mu M for both analytes. The detection limits (LODs) for IMD and FIP were determined as 0.97 mu M and 0.81 mu M, respectively. The recovery percentages for IMD and FIP in environmental water samples varied from 90.0%-105.0%. 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. (c) 2020 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited