Our study aims to develop and validate a newly precise analysis method for simultaneous determination of metalaxyl-M and azoxystrobin residues in wastewater samples. The analysis was done by a series-200 HPLC equipped with a UV detector and C18 column used for separation. Chromatographic separation utilized a mobile phase of 60% acetonitrile and 40% water by volume flowing at a constant rate of 1.2 mL/min and the quantification was performed by measuring absorbance at 275 nm. The proposed method was systematically validated in terms of linearity, accuracy, precision, recovery, limit of detection (LOD), and limit of quantification (LOQ) in compliance with SANCO/3030/99 rev.5 requirements. Calibration curves exhibited excellent linearity (R² > 0.990) across the tested concentration ranges. The obtained LOD and LOQ values indicated high method sensitivity, enabling the reliable quantification of trace levels in complex wastewater matrices. Recovery tests performed at three spiking levels demonstrated satisfactory recoveries ranging from 100.2% to 101.3% for metalaxyl-M and from 99.7% to 101.2% for azoxystrobin, confirming the robustness and reliability of the developed procedure. Overall, the validated HPLC method serves as a versatile, rapid, and economical analytical tool applicable to different environmental and agricultural samples for the monitoring of fungicide residues.

Metalaxyl-M is a modern and more efficient version of metalaxyl which is designated to provide effective control of damaging fungal diseases. This work aimed to develop and validate a low-cost, accurate, fast, and simple analytical method for determination of active ingredient metalaxyl-M using high-performance liquid chromatography with ultraviolet detection (HPLC-UV). The development of the novel method was performed on reversed-phase brownlee™ C-18 column at constant temperature 30 ºC. The mobile phase consists of acetonitrile and distilled water in volumetric ratio 62.5:37.5, a flow rate of 1.2 mL/min, and the detective wavelength at 270 nm. The validation protocol underscore in our study was SANCO/3030/99 rev. 5. Specificity, linearity, LOD, LOQ, precision, recovery, and accuracy parameters were calculated and discussed. The values for multiple correlation coefficient (R² ≥ 0.990), relative standard deviation (RSD < 1.5 %), recoveries ranged from (99.21 - 101.16 %) were found within acceptance criteria.

This research introduces an eco-friendly green Reverse-Phase High Performance Liquid Chromatography (RP-HPLC) method for detecting and quantifying meropenem trihydrate. Traditional methods use buffered solutions, gradient mobile phases, and longer retention times, but this method offers a rapid RP-HPLC technique with a C8 column and isocratic mobile phase (60% methanol, 40% ultra-pure water), eliminating the need for buffers and acetonitrile. It features a short 2.1-minute retention time and a high r² value of 0.9995. It delivers accuracy (101.1-102.3%) and precision (RSD ≤ 2%), coupled with low LOD and LOQ values of 1.72 and 5.20 µg/ml. Aqueous dilution simplifies sample preparation, reducing degradation and interference. The method is compared with an HPTLC method, showing an extended linear range (6.25-200 µg/ml for HPLC, 7.81-62.5 µg/ml for TLC) and high sensitivity, making it significant for meropenem trihydrate quality control in bulk and dosage forms.

Due to the new hopes for treatment of multiple sclerosis (MS) diseases by Teriflunomide (TFN), in this project, a cheap, robust, and fully validated method has been developed both for determination of assay content in API (active pharmaceutical ingredient), and for related impurities analysis (RIA). To operate the method, a common C18, end-capped (250 × 4.6) mm, 5µm liquid chromatography column, was applied. The mobile phase A was prepared by dissolving 2.74 g (20mM) of PDP (potassium dihydrogen phosphate) and 3.72 g (50mM) of PC (potassium chloride) in water (1000 mL). Then, pH was adjusted to 3.0 by adding OPA (ortho-phosphoric acid) 85%; while, the mobile phase B was acetonitrile (ACN) (100%). In order to confirm the experimental data about the λmax of TFN, we have used the Born-Oppenheimer molecular dynamics (BOMD) simulations, quantum mechanics (QM), and TD-DFT calculations. According to the results, the method showed a high level of suitability, specificity, linearity, accuracy, precision, repeatability, robustness, and reliable detection limit.

Enzymatic assay, based on oxidation-reduction reaction catalyzed by alcohol dehydrogenase, is one of the methods used to determine ethanol concentration. The present study was directed to determine the exact amount of enzyme required to accomplish oxidation-reduction reaction so that the concentration of ethanol in the sample can be determined precisely and accurately. Results of the present study indicate that the lowest unit activity of the enzyme that can be used for ethanol determination is 4000 units/mL, even though longer incubation time compared to the original method was used to ensure reaction completion. Validation of the method confirmed that the assay have acceptable linearity range within 0.01 - 0.06% (v/v) of ethanol with correlation coefficient of 0.9999. Both accuracy and precision parameters fulfill the Association of Analytical Communities (AOAC) International requirement, and therefore can be accepted as a quantitative analysis method. Limit of detection and limit of quantitation for the modified method were 0.0017% (v/v) and 0.0056% (v/v), respectively.