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In recent years, multivariate optimization has played an increasing role in analytical method development. ICH guidelines recommend using statistical design of experiments to identify the design space, in which multivariate combinations of composition variables and process variables have been demonstrated to provide quality results. Considering a microemulsion electrokinetic chromatography method...
A simple micellar electrokinetic chromatography (MEKC) method for the simultaneous determination of 2-furfural (2-F), 3-furfural (3-F), 5-methylfurfural (5-MF), 5-hydroxymethylfurfural (5-HMF), 2-furoic acid (2-FA) and 3-furoic acid (3-FA) in honey and vegetable oils is described. Parameters affecting the separation such as pH, buffer and surfactant concentrations, applied voltage, capillary temperature,...
A novel automated immunosensor assay has been developed for real-time measurement of the breast cancer biomarker CA15-3 in serum. The assay employed the kinetic-exclusion analytical technology of the KinExA™ 3200 instrument. Polymethylmethacrylate (PMMA) beads coated with CA15-3 were used as capturing reagent, mouse anti-CA15-3 monoclonal antibody was used as primary antibody, and the fluorescence...
A feasibility test for rice peroxidase (RP) enzyme as a substitute for horseradish peroxidase (HRP) was carried out. The activity of HRP was maximum at 30°C with pH 6.0–7.0. The purified rice peroxidase showed optimum activity at 30°C with pH 7–8 and was thermostable till 68°C, which is higher than the temperature reported for HRP. RP obeyed Michaelis–Menten kinetics. With increasing substrate concentrations,...
A new ditopic ion pair receptor 1 containing two biindole moieties and a bis-benzocrown ether unit shows a remarkable color switching (ON- and -OFF) function induced by anion (F − ) and cation (K + ) recognition. The ditopic receptor 1 binds in a cooperative fashion to HSO 4− in the presence of 1·K + and acts as a selective ditopic receptor to recognize ion pairs...
A simple and sensitive on-line solid-phase extraction methodology for preconcentration and determination of trace amounts of Cd(II), Pd(II) and Cu(II) in natural water samples has been developed using the strong cation exchange capability of Bond Elut ® Plexa™ PCX polymer resin. Plexa PCX is a mixed-mode sorbent, commercially available in a cartridge format and as far as we know, there is...
Screening of relevant factors using Plackett–Burman designs is usual in analytical chemistry. It relies on the assumption that factor interactions are negligible; however, failure of recognizing such interactions may lead to incorrect results. Factor associations can be revealed by feature selection techniques such as ant colony optimization. This method has been combined with a Monte Carlo approach,...
Ionic liquids (ILs) with l-proline (l-Pro) as cations have been developed for the novel chiral ligands coordinated with Cu(II) in chiral ligand exchange capillary electrophoresis (CLE-CE). Four kinds of amino acid ionic liquids (AAILs), including [l-Pro][CF 3 COO], [l-Pro][NO 3 ], [l-Pro][BF 4 ] and [l-Pro 2 ][SO 4 ], were successfully synthesized. Among them,...
A coupling of thin layer chromatography with laser ablation ICP SF MS was developed for the fractionation of Ni, V, Fe and S in crude oil and its fractions (saturate, aromatic, resin and asphaltene). The detection limits were 18ngg −1 and 23ngg −1 for nickel and vanadium, respectively, and a sample could be characterized in terms of the metal distribution as a function of species polarity...
Solid-phase extraction (SPE) is often used for preconcentration and determination of metal ions from industrial and natural samples. A traditional single variable approach (SVA) is still often carried out for optimization in analytical chemistry. Since there is always a risk of not finding the real optimum by single variation method, more advanced optimization approaches such as multivariable approach...
A novel carbon paste electrode based on functionlized multi-walled carbon nanotubes/β-cyclodextrin composite (FMWCNTs/β-CD-CPE) is described for potentiometric determination of piroxicam (PXM). Improved sensitivity and selectivity was achieved by application of CDs as molecular host–guest recognition elements and MWCNTs. The electrochemical performance of carbon paste electrodes incroporated with...
This study describes the optimization and validation of a quick and simple method for the simultaneous determination of total content and available fractions of As, Cr, Cu, Ni, Pb and Tl in sediments by ET AAS, which has been proved to be useful for environmental research. The optimization was carried out using a 3 3 Box–Behnken factorial design which was applied to matrices of total digestion...
A novel and simple method was presented for micrococcal nuclease (MNase) detection based on fluorescence resonance energy transfer (FRET) realized by electrostatic interaction. In this study, mercaptoacetic acid capped quantum dots (MAA-QDs) and ROX-modified single-stranded DNA (ROX-ssDNA) were chosen as energy donor and acceptor, respectively. At slightly basic pH, the positively charged peptide...
An automated analysis system has been developed for measuring perchlorate concentration in atmospheric aerosol. The perchlorate in aerosol sample, which has been collected with water mist in a hydrophobic filter/mist chamber based particle collector, is continuously preconcentrated. The matrix ions such as sulfate are subsequently removed from the preconcentrator. The remaining perchlorate is then...
Aconite poisoning is one of the most serious types of herb-related medical emergencies. In Hong Kong, many if not most of these poisoning cases are due to confusion in herbal species; that is, the wrong herbs are used in prescriptions. Such human errors, while inevitable perhaps, can be serious, and sometimes fatal. The chemical components responsible for aconite poisoning are yunaconitine and crassicauline...
Carbon nanotube-reinforced hollow fiber solid-phase microextraction (CNTs-HF-SPME) combined with high-performance liquid chromatography (HPLC) was used to extract and determine diethylstilbestrol (DES) in milk products. Wall pores of the hollow fiber were filled with multi-walled carbon nanotubes (MWCNTs) using sol–gel technology. In the proposed method, DES was selectively extracted by MWCNTs, desorbed...
This work combines lab-on-paper methodology with nanoparticle science to develop a new tool for the simple and rapid determination of Hg(II). The resulting paper-based device enables measurement of Hg(II) from only 2μL of sample solution. The color of the nanosilver in the test area immediately changes in the presence of Hg(II), and this change can be monitored by the naked eye. This method exhibits...
Oysters are one of foodstuffs containing a relatively high amount of cadmium. Here we report on establishment of an immunochromatographic assay (ICA) method of cadmium levels in oysters. Cadmium was extracted with 0.lmolL −1 HCl from oysters and cleaned up from other metals by the use of an anion-exchange column. The behavior of five metals Mn, Fe, Cu, Zn, and Cd was monitored at each step...
Inhibition of the α-glucosidase activity is a therapeutic approach for diabetes. In this study, an effective strategy for screening α-glucosidase inhibitors based on Nuclear magnetic resonance (NMR) techniques was developed to screen and identify α-glucosidase inhibitors from Mulberry leaf extract. As a result, deoxynojirimycin, as a potential α-glucosidase inhibitor, was found. The study suggested...
This paper reviews the entire recent global tendency for creatinine measurement. Creatinine biosensors involve complex relationships between biology and micro-mechatronics to which the blood is subjected. Comparison between new and old methods shows that new techniques (e.g. Molecular Imprinted Polymers based algorithms) are better than old methods (e.g. Elisa) in terms of stability and linear range...
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