Synthesis and Characterization of Molecularly Imprinted Polymers for Phenoxyacetic Acids

2-methylphenoxyacetic acid (2-MPA), 2-methyl-4-chlorophenxyacetic acid (MCPA) and 4-chlorophenoxyacetic acid (4-CPA) were imprinted to investigate the cross-selectivities of molecularly imprinted polymers (MIPs). The result indicates that 2-MPA, which is similar in shape, size and functionality with phenoxyacetic herbicides, are suitable to be used as a suitable template to prepare the MIPs for retaining phenoxyacetic herbicides. To study the ion-pair interactions between template molecules and functional monomer 4-vinylpiridine (4-VP), computational molecular modeling was employed. The data indicate that the cross-selectivities of MIPs for phenoxyacetic acid herbicides depend on the binding energies of complexes

Study on the XPS-ESCA of Aluminum Phosphide Products

XPS-ESCA analysis showed small signal for phosphorus in fresh specimens of aluminum phosphide (AlP). After removal of a layer of about 0.5 – 1.0 μm by argon ion sputtering, it was observed that signal intensities from oxygen and aluminum increased. The oxygen signal decreased as a function of sputtering time, synchronously with the increase of the phosphorous signal from the AlP nucleus. The aluminum signal, which was considered to be mainly due to AlP and Al(OH)3, remained constant. Other impurity elements including N, Mg, etc., were identified in the technical 85% AlP and AlP tablet formulated products

Determination of Trace Level of cAMP in Locusta Migratoria Manilensis Meyen by HPLC with Fluorescence Derivation

Abstract: A sensitive and rapid method was developed for the determination of cAMP in Locusta migratoria manilensis Meyen by high-performance liquid chromatography with fluorescence detection. The cAMP was derivatized using chloroacetaldehyde and TBAS buffer/methanol was used as the mobile phase. A detection quantification of 40 fmol/ml could be achieved when using fluorescence detection. An HPLC-MS method using DMHA as an ion-pair agent to analyze cAMP was also demonstrated. We studied the effect of dopamine and other stimulants on cAMP levels from isolated locust central nervous systems. The new method is well suited for the analysis of cAMP in small biological samples

Ionic Liquid-Dispersive Micro-Extraction and Detection by High Performance Liquid Chromatography–Mass Spectrometry for Antifouling Biocides in Water

A simple analytical method was developed and evaluated for the determination of two antifouling biocides using an ionic liquid-dispersive liquid–liquid micro-extraction (IL-DLLME) and a high-performance liquid chromatography–electrospray ionization mass spectrometry (LC-ESI-MS) analysis. Irgarol 1051 and Sea-Nine 211 were extracted from deionized water, lake water, and seawater using IL 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIm][PF6]) and ethyl acetate as the extraction solvent and the dispersion solvent. Several factors were considered, including the type and volume of extraction and dispersive solvent, IL amount, sample pH, salt effect, and cooling temperature. The developed method resulted in a recovery range of 78.7–90.3%, with a relative standard deviation (RSD, n = 3) less than 7.5%. The analytes were enriched greater than 40-fold, and the limits of detection (LOD) for two antifouling biocides were 0.01–0.1 μg L−1. The method was effectively applied for the analysis of real samples of freshwater as well as samples of seawater

Pesticide Residue Behavior and Risk Assessment in Celery after Se Nanoparticles Application

This study investigates pesticide levels in celery, and compares their degradation, dissipation, distribution, and dietary risk after spraying with selenium (Se) nanoparticles. Abamectin, imidacloprid, acetamiprid, thiamethoxam, and lambda-cyhalothrin were sprayed at 1.6, 6.8, 2.0, 1.0, and 0.7 g a.i. ha−1 followed by a 2 g·ha−1 Se nanoparticle application during the growing period. Thiamethoxam, abamectin, imidacloprid, lambda-cyhalothrin, and acetamiprid in celery degraded following a first order kinetic model after 2 g·ha−1 Se nanoparticles application. With the exception of acetamiprid, the half-lives of thiamethoxam, abamectin, imidacloprid, and lambda-cyhalothrin were reduced from 2.4, 0.5, 1.2, 4.2 days without Se nanoparticles application to 1.4, 0.2, 0.9, 3.7 days with the addition of Se nanoparticles (2 g·ha−1), respectively. The chronic dietary exposure risk probability (RQc) and the acute dietary exposure risk probability (RQa) of celery after Se nanoparticles application were within acceptable limits for consumption except for abamectin