Metrohm China Ltd.

Beijing, China

Metrohm China Ltd.

Beijing, China
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Li Y.,University of South China | Xiong M.,University of South China | Yin C.,Metrohm China Ltd. | Wu F.,University of South China | And 2 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2012

In order to improve the physiological functions of dietary fiber from sweet potato residue, insoluble dietary fiber (IDF) was prepared from sweet potato residue for physical and chemical properties ultra-high pressure modification with uniform test method. And insoluble dietary fiber was characterised by the methods of SEM, HPCE, FT-IR, XRD, BET and particle size. The conclusion shows that the pressure (X 1), processing time (X 2) and temperature (X 3) had the significant influences on glucose regulation, blood fat regulation and the ability of removing exogenous harmful substances in modified IDF. The optimum processing conditions were that the glucose regulation and blood fat regulation capacity were pressure of 600 MPa, processing time of 15 min and temperature of 60°C; The ability of removing exogenous harmful substances were pressure of 100 MPa, processing time of 10 min and temperature of 42°C. The physicochemical property shows that the microstructure of sweet potato residue IDF modified by the ultra-high pressure was loose, smooth, porous with honeycomb-shaped and massive structure. Either modification didn't affect the monosaccharide compositions, but the contents of monosaccharide changed a little. Meanwhile, crystal and particle size of modified IDF reduced, the specific surface area increased. The characteristic absorption peaks enhanced and a red shift or blue shift appeared, and a number of new absorption peaks occured. The research can provide a reference for functional modifications and utilization of dietary fiber from sweet potato residue.


Wang Z.-H.,Qingdao University | Xia J.-F.,Qingdao University | Zhao F.-Y.,Qingdao University | Zhao F.-Y.,Metrohm China Ltd. | And 4 more authors.
Chinese Chemical Letters | Year: 2013

A simple, fast, precise and eco-friendly method, based on ion chromatography (IC) with a suppressed conductivity detector, was proposed for the determination of benzoic acid (BA) in milk in this paper. The chromatographic separation was accomplished by using an anion exchange column eluted with 3.2 mmol/L aqueous Na2CO3 and 1.0 mmol/L aqueous NaHCO3 at a flow-rate of 0.7 mL/min. The method validation experiment provided excellent results with respect to linearity (correlation coefficient up to 0.9997), limit of detection (0.1 μg/L), recovery values (ranging from 88.0% to 93.0%) and relative standard deviation (RSD) (below 2.2%, n = 7). © 2013 Zong-Hua Wang.


Li Y.,Metrohm China Ltd Company | Yu H.,Metrohm China Ltd Company | Wang F.,Qinhuangdao Entry Exit Inspection and Quarantine Bureau
Chinese Journal of Chromatography (Se Pu) | Year: 2016

An ion chromatographic method was developed for the determination of perchlorate in wine. The content of perchlorate in four kinds of wine was determined. Metrosep A Supp5 column (150 mm×4.0 mm) was used for the separation with the eluent of 1.0 mmol/L Na2CO3-acetone (85: 15, v/v) at the flow rate of 0.8 mL/min, and the column temperature was 40°. Perchlorate had good linearity in the range of 0.1-10.0 mg/L. The recoveries of the method were more than 86.0%, and the relative standard deviations were less than 2.6%. The method is simple and rapid, and can be used for the determination of perchlorate in wine.


Tao L.,Metrohm China Ltd. | Sun H.,Metrohm China Ltd. | Gong Y.,Metrohm China Ltd. | Li T.,Metrohm China Ltd.
Yejin Fenxi/Metallurgical Analysis | Year: 2012

The aluminum profile surface was usually treated by some chemical methods such as acid treatment to improve the protective property and functionality, enlarge the application range and prolong the use life. The wastewater generated in aluminum profile surface treatment contained high-concentration H + and Al 3+. Therefore, the effective monitoring of their content had important significance whether in process control or environmental protection. In this study, the content of H + and Al 3+ in wastewater was quantitatively determined by thermometric titration in first time. This method was applied to the determination of actual wastewater from aluminum factory. The results showed that the found results of this method were consistent with the theoretical values or those obtained by conventional manual titration. The recoveries of method were 99.8% and 104.1% for H + and Al 3+, respectively. The relative standard deviations (RSD, n=7) in precision test were both less than 2% for H + and Al 3+.


Huo S.,Metrohm China Ltd | Luo Q.,Metrohm China Ltd | Cao L.,Metrohm China Ltd
Chinese Journal of Chromatography (Se Pu) | Year: 2016

A new method for the determination of the hexafluorosilicic acid in the wasted hydrofluoric acid by ion chromatography (IC) with UV-Vis (ultraviolet-visible) detector after post column reaction was investigated. The wasted hydrofluoric acid was produced in the silicon etching bath. The separation was achieved on a Metrosep A Supp 7 column with 3.2 mmol/L sodium carbonate and 1.0 mmol/L sodium bicarbonate at a flow rate of 0.7 mL/min. In this thesis, the derivatization reaction temperature, reagent adding rate and the UV detector wavelength were studied. The other mineral acids in the etching bath, such as hydrofluoric acid, chloric acid, nitric acid, phosphoric acid, acetic acid and sulfuric acid also could be determined in the same time by the suppressed conductivity detection. The method showed that hexafluorosilicic acid had good linearities in the range of 2.4-120 mg/L. The average recovery of the hexafluorosilicic acid in the real sample was 97.2%. The limit of quantification of hexafluorosilicic acid was 0.24 mg/L. The method is accurate, fast and suitable for the determination of hexafluorosilicic acid in the etching bath solution.


Liu Y.,Metrohm China Ltd | Yu H.,Metrohm China Ltd
Chinese Journal of Chromatography (Se Pu) | Year: 2016

An analytical method for the determination of β-glycerophosphate and L-malate in glycerol phosphate preparations was established by ion chromatography with isocratic elution. α-Glycerol phosphate was completely separated from β-glycerol phosphate in the glycerol phosphate preparations. A Metrosep A Supp7 column (250 mm×4.0 mm, 5 μm) was used for separation with the eluent of 3.6 mmol/L Na2CO3 at a flow rate of 0.7 mL/min. The column temperature was 35 °C. With this method, good accuracy and precision were obtained. The recoveries of the method ranged from 90.73% to 106.27%. The method is simple, rapid, sensitive, and suitable for the determination of β-glycerophosphate and L-malate in glycerol phosphate preparations.

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