Entity

Time filter

Source Type


Li W.,East China University of Science and Technology | Wang H.,Technical Center for Industrial Products and Raw Materials Inspection and Testing | Jiang W.,Technical Center for Industrial Products and Raw Materials Inspection and Testing | Wang L.,East China University of Science and Technology | And 4 more authors.
Analytical Methods | Year: 2016

Membrane filtration (microfiltration) as a solid-phase extraction technique with features of rapidity, simplicity of operation, low cost, and high enrichment efficiency has received considerable attention and has been widely used for separating and enriching analytes from fluids. On the basis of our previous study, a very simple but effective mode of multilayer membrane filtration-enrichment process was introduced into the case of quantitative detecting of two or more analytes in mixture samples to achieve the target of separating and concentrating analytes simultaneously. A case study was carried out to assess this method utilizing the carcinogenic dyes rhodamine B (RhB) and acid orange 7 as model analytes. Under the optimal conditions, linearity of the calibration curve based on the Kubelka-Munk function was achieved in the concentration range of 3-30 μg L-1 with the correlation coefficients (R2) of 0.9982 and 0.9952 for RhB and acid orange 7, respectively. Good repeatability was achieved utilizing 30, 10 and 5 μg L-1 solutions with the relative standard deviations (RSDs) of 3.1-6.4% for RhB and 2.4-5.8% for acid orange 7. The presented method was successfully employed to simultaneously quantify RhB and acid orange 7 in soft drink and candy samples. © The Royal Society of Chemistry 2016. Source


Wu T.,East China University of Science and Technology | Hu H.,East China University of Science and Technology | Jiang D.,East China University of Science and Technology | Du Y.,East China University of Science and Technology | And 2 more authors.
Polymer Testing | Year: 2013

The main goal of this work is to identify two polyamides (PA11 and PA1012) by mass spectrometry including pyrolysis-GC/MS and MALDI-TOF MS. PA11 and PA1012 have similar properties and cannot be distinguished by many other methods. Using pyrolysis-GC/MS, the pyrograms of PA11 and PA1012 at 600 °C were compared. Specific pyrolyzates for PA11 and PA1012 were obtained, 2-azacyclotridecanone for PA11 and 1,10-diaminodecane, 1,10-dicyanodecane for PA1012, respectively, which was the basis to distinguish them. Meanwhile, MALDI-TOF MS can give specific repeat unit for these two polyamides, dehydrated 11-aminoundecanoic acid (M = 183) for PA11, acetylate of dodecanedioic acid and diaminodecane (M = 366) for PA1012, which can be another means of identifying them. © 2012 Elsevier Ltd. All rights reserved. Source


Li W.,East China University of Science and Technology | Zhang R.,East China University of Science and Technology | Wang H.,Technical Center for Industrial Products and Raw Materials Inspection and Testing | Jiang W.,Technical Center for Industrial Products and Raw Materials Inspection and Testing | And 4 more authors.
Analytical Methods | Year: 2016

The digital image colorimetry technique was combined with the multichannel membrane filtration-enrichment technique proposed in our previous study to increase its sensitivity. With our multichannel device, six solutions including standard and test samples were enriched and distributed evenly in a circle form on one membrane filter. A digital image of the membrane filter was taken utilizing a mobile phone equipped with a digital camera after filtration. Then the RGB responses for each sample spot were extracted from different regions of the same picture using Adobe Photoshop. The obtained RGB responses (value of the blue component, B) could be utilized directly for quantitative analysis when the picture was taken under a uniform illumination. In addition, the total intensity I (I = R + G + B) was used to minimize the effect of the illumination to the RGB responses, so that the conditions for taking pictures can be softened to a casual environment. A case study was carried out to assess this method utilizing the carcinogenic dyes, Sudan I, Chrysoidine G, Auramine O and Acid orange 7 as model analytes. Under the optimal conditions, there was a quadratic function relationship between the negative value of B/I and the concentration in the concentration range of 3-40 μg L-1 with the squared correlation coefficient (R2) for the four dyes all being above 0.9950. Linear calibration curves were achieved only at a low concentration level and the corresponding limit of detections (LODs) were 1.03 μg L-1 for Sudan I, 3.0 μg L-1 for Chrysoidine G, 2.11 μg L-1 for Acid orange 7, and 0.65 μg L-1 for Auramine O. For each dye, good repeatability was achieved with relative standard deviation (RSD) values all below 3.8%. The results obtained from digital image colorimetry were similar to those obtained from spectral analysis, which proved the accuracy of this method. And the presented method was successfully employed to quantify Sudan I and Acid orange 7 in candy samples, and Chrysoidine G and Auramine O in soft drink samples. © The Royal Society of Chemistry 2016. Source


Liu B.,East China University of Science and Technology | Jiang W.,Technical Center for Industrial Products and Raw Materials Inspection and Testing | Wang H.,Technical Center for Industrial Products and Raw Materials Inspection and Testing | Yang X.,East China University of Science and Technology | And 4 more authors.
Microchimica Acta | Year: 2013

We report on a microfluidic platform that integrates a winding microdroplet chip and a surface-enhanced Raman scattering (SERS) detection system for trace determination of crystal violet (CV). Colloidal silver was applied to generate SERS. Compared to the continuous flow microfluidic system, the microdroplet based detection described here effectively eliminates any memory effects. Effects of flow pattern, droplet size, surfactant, and position of detection were optimized. Under optimal conditions, there is a linear correlation between signal and the concentration of CV in the 10 nM to 800 nM range, with a correlation coefficient (R2) of 0.9967. The limit of detection in water is 3.6 nM. [Figure not available: see fulltext.] © 2013 Springer-Verlag Wien. Source


Wu T.,East China University of Science and Technology | Wang H.-T.,Technical Center for Industrial Products and Raw Materials Inspection and Testing | Shen B.,Technical Center for Industrial Products and Raw Materials Inspection and Testing | Du Y.-P.,East China University of Science and Technology | And 4 more authors.
Chinese Chemical Letters | Year: 2016

Primary aromatic amines (PAAs) are substances with toxicity and suspected human carcinogenicity. A facile method for highly sensitive detection of PAAs using surface-enhanced Raman spectroscopy (SERS) is reported. The immobilization of Au nanoparticles (AuNPs) on the glycidyl methacrylate-ethylene dimethacrylate (GMA-EDMA) materials makes the substrate a closely packed but not aggregated Au NP arrays which provides a prominent SERS enhancement. Four PAAs with different substituent groups, namely, p-toluidine, p-nitroaniline, benzidine and 4,4-methylene-bis-(2-chloroaniline) have been successfully identified and quantified. High sensitivity and good linear relationship between SERS signals and concentrations of PAAs are obtained for all four PAAs. © 2016 Ting Wu. Source

Discover hidden collaborations