Optimization Of Key Factors Research Articles

MIL-53/UiO-66/PAN beads as a novel adsorbent for simultaneous extraction of trace pesticides in wheat, wheat flour and field soil followed by GC-MS analysis

To develop a facile, efficient and sensitive method for simultaneous determination of multiple pesticides in wheat, wheat flour and field soil, a novel MIL-53/UiO-66/PAN bead was successfully prepared and applied as adsorbent in a simplified dispersive solid-phase extraction (d-SPE) followed by GC-MS analysis. Moreover, the MIL-53/UiO-66/PAN bead could be directly separated owing to its scale of millimeter, which overcome the shortcomings of traditional d-SPE. After optimization of key factors by Response Surface Methodology, the proposed method exhibited excellent linearity (R2> 0.99) and detection limits of 0.17-1.21µg/L. Furthermore, recoveries were in range of 77.8-98.3%, with RSDs lower than 9.2%. Finally, the developed method was successfully applied to the determination of pesticides in wheat, wheat flour and soil from wheat field, where Triadimefon was detected in wheat and soil samples at a concentration of 28.7 and 36.9µg/kg, respectively. The results demonstrated that the MIL-53/UiO-66/PAN-based d-SPE-GC-MS method provided a more convenient strategy for efficient extraction and determination of pesticides in wheat, wheat flour and field soil.

Photocatalytic degradation of acetaminophen using a novel TiO2-orange peel-derived biochar composite: Synthesize, characterization and optimization of key factors

The widespread presence of pharmaceutical pollutants like acetaminophen (ACT) poses a significant threat to aquatic ecosystems and human well-being. Herein, we employed a straightforward ultrasonic technique to synthesize TiO2 integrated with biochar derived from orange peel waste (TOBC) for the photocatalytic degradation of ACT. Parameters for the synthesis of TOBC, including biochar loading, ultrasonic power, and time, were optimized via Design Expert software and central composite design for response surface methodology (RSM-CCD). The resulting TiO2-orange peel-derived biochar 20 wt% (TOBC20) exhibited remarkable photocatalytic efficacy, achieving 94 % ACT degradation under optimized conditions (initial concentration = 20 mg. L−1, pH = 4, irradiation duration = 100 min, and catalyst dosage = 0.8 g. L−1). Thorough characterization, including XRD, FTIR, XPS, SEM, EDX, PL, EIS, and TPC analyses, offered insights into the biochar's innovative role as an electron acceptor and in separating electron-hole pairs. Trapping tests and ESR techniques elucidated the photocatalytic degradation mechanism, and the TOBC catalyst also demonstrated consistent stability over five cycles, confirming its suitability for eliminating non-biodegradable pharmaceuticals. Finally, results were validated by comparison with previous research, showing relatively consistent findings.

Nitronyl nitroxide monoradical TEMPO as new electrochemical label for ultrasensitive detection of nucleic acids

In this work, a novel electrochemical biosensor based on nitronyl nitroxide monoradical 2,2,6,6-tetramethylpiperidine 1-Oxyl (TEMPO) as new electrochemical label for facile nucleic acids detection is developed. This fast and convenient functional microelectrode was designed by fixing the capture probe peptide nucleic acid (PNA) and using the coordination interaction of Zr4+ with both phosphate groups and carboxyl groups. Differential pulse voltammetry (DPV) was used to study the oxidation current of TEMPO which was combined with the electrode surface and labeled. TEMPO electrochemical signal related to target deoxyribonucleic acid (tDNA) concentration was finally detected when tDNA was added on the surface of glassy carbon electrode (GCE). The detection principle, optimization of key factors and performance analysis of the biosensor are also discussed. A great linear relation is acquired within the scope of 10 pM–100 nM under optimal conditions and the detection limit of this experiment is calculated as low as 2.57 pM (R2 = 0.996). In addition, complex serum samples were used to explore the practical application of this experiment. The results show the developed electrochemical DNA biosensor has wide application prospects in nucleic acids detection and clinical analysis.

Highly sensitive detection of lipopolysaccharide based on collaborative amplification of dual enzymes

In this work, a novel electrochemical biosensor is developed for facile and highly sensitive detection of lipopolysaccharide (LPS) based on collaboration of dual enzymes for multiple-stages signal amplification. Through ingenious design, the specific recognition of target LPS is transformed to the exonuclease III (Exo III)-assisted interface DNA cycling collaborated with the terminal deoxynucleotidyl transferase (TdT)-catalyzed DNA extension, finally inducing significant electrochemical signal concerned with the concentration of LPS. This paper mainly discusses the detection principle, optimization of key factors, and the analytical performance of the biosensor. With the efficient signal amplification, the biosensor shows high sensitivity with a good linearity and a low limit of detection of 1 pg mL−1 for LPS. Moreover, the developed biosensor can clearly discriminate LPS from interferents and show high specificity for LPS detection. This biosensor has also been successfully employed to measure LPS in real food samples, suggesting potential opportunity for application in food safety detection.

MIP-capped terbium MOF-76 for the selective fluorometric detection of cefixime after its preconcentration with magnetic graphene oxide

Herein, a sensitive and reliable fluorometric probe based on the molecular imprinted polymer capped terbium metal-organic frameworks (MIP@TbMOF-76) was introduced for the measurement of cefixime. The MIP@TbMOF-76 composite was prepared by simple co-polymerization of definite monomers and cross-linkers in the presence of TbMOF-76 as support and cefixime as the model template molecules. After the removing of template molecules, the obtained composite had an intense fluorescence emission corresponding to the terbium emission spectra which undergo a sensible diminution in the presence of cefixime. The prepared MIP@TbMOF-76 indicated a great affinity to adsorb cefixime molecules, which could linearly quench the emission intensity. Moreover, an extraction process using magnetic Fe3O4@SiO2 modified graphene oxide (Fe3O4/GO) was applied for the efficient preconcentration of cefixime from aqueous solution to access its very low concentrations. Based on this procedure, an ultrasensitive and selective probe was designed for cefixime. After optimization of key factors, a calibration graph was achieved in the concentration range of 0.8–90 ng mL−1 cefixime, with a detection limit (3 s) of 0.34 ng mL−1. The developed probe had a good precision (RSD% < 3.6) and was acceptably used for the determination of cefixime in pharmaceutical and human urine samples.

Using experimental design for the screening and optimization of key factors on silica particles adsorption using magnetic nanoparticles – a case study of chemical mechanical polishing wastewater treatment

This study applied magnetic nanoparticles (MNPs) to chemical mechanical polishing wastewater treatment using experimental design (Plackett–Burman methods) to select the key factors among pH, mixing, Polyaluminum chloride dosage, settling time, MNPs dosage, and temperature and using response surface methodology (RSM) to determine the optimal values of key factors. Research results showed that the key factors influencing processing performance were pH and rpm, and the optimal conditions were a pH of 4.9 and rpm of 68. The turbidity removal rate through RSM simulation was 90%; under this parameter, the actual turbidity removal rate in the experiment was 89%, which was extremely close to the simulation value; this value was also much higher than the nonoptimized removal rate of 61 ± 8%. Additionally, in the subsequent regeneration and reuse experiment involving mixing and ultrasound for desorption and regeneration, the number of recoveries were 4 and 5, respectively. The study showed that the average particle size of MNPs following ultrasonic vibration was reduced; the effect was optimal at 23 to 15 nm. Therefore, a removal rate of over 80% could be maintained for the fifth ultrasonic regeneration, and the energy of the mixing method may not have been sufficient, causing incomplete desorption and a turbidity removal rate of only 71%.