-
[show abstract]
[hide abstract]
ABSTRACT: An ion-chromatographic (IC) system with high selectivity for separation of nitrite is described. It is analogous to the EIC (electrostatic IC) previously reported and was established using 3-(N,N-dimethylstearylammonio)propanesulfonate (C23H49NO3S, a sulfobetaine type of zwitterionic surfactants) as the stationary phase and dilute aqueous HCl solutions as the mobile phase. Five inorganic anions, sulfate, chloride, bromide, nitrate, and nitrite were chosen as the model analytes and were analyzed using this EIC system. Sulfate was always eluted first, followed by chloride, bromide and nitrate. Nitrite, however, could be eluted either before or after nitrate, depending on the concentration of HCl in the eluent. An elution order nitrate< nitrite was always obtained simply by using >3 mmol L(-1) HCl as the eluent. For nitrite the detection limit was better than 2.1 x 10(-7) mol L(-1) (100 microL sample injection volume, S/N=3, UV at 210 nm). Bromide and nitrate could also be separated under these HPLC conditions. The detection limit for bromide was 7.2 x 10(-8) mol L(-1) and for nitrate 6.5 x 10(-8) mol L(-1). Both nitrite and nitrate in real seawater samples were successfully determined with direct sample injection using this EIC system.
Fresenius Journal of Analytical Chemistry 12/2001; 371(8):1109-12.
-
[show abstract]
[hide abstract]
ABSTRACT: A high performance liquid chromatographic method with a diol column and evaporative light scattering detector (ELSD) was established for the direct analysis of fructose, glucose, sucrose, maltose and raffinose in mixture. A separation column (Lichrospher 100 Diol, 250 mm x 4.0 mm i.d., 5 microns, Hewlett-Packard, USA) and a guard column (Zorbax Rx-SIL, 12.5 mm x 4.6 mm i.d., 5 microns) were used. The mobile phase was a mixture of dichloromethane-methanol (3.2:1, volume ratio). Regression equations revealed linear relationship (correlation coefficients: 0.995-0.999) between the mass of carbohydrates injected and the peak area of carbohydrates detected by ELSD. The detection limits of ELSD (S/N = 3) were about 0.20 microgram for all carbohydrates. This system could be used for the routine analysis of simple carbohydrates in some common drinks on market.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 12/2001; 19(6):520-2.
-
[show abstract]
[hide abstract]
ABSTRACT: The reaction of p-hydroxybenzyl alcohol and hydroxyl radicals generated by the Fenton reaction is studied. The products of the reaction are separated and identified by high-performance liquid chromatography (HPLC)-diode-array detection and HPLC-mass spectrometry. According to the structures of the products, a mechanism of the reaction is proposed.
Journal of chromatographic science 10/2001; 39(9):393-6. · 0.88 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A simple, sensitive, and reliable method using gas chromatography (GC)-mass spectrometry (MS) is developed for the simultaneous determination of ephedrine alkaloids and 2,3,5,6-tetramethylpyrazine (TMP) in Ephedra sinica Stapf. The sample is extracted with ethyl ether and submitted to GC-MS for identification and quantitation without derivatization. The column used for GC is an HP-5 (30.0 m x 250 microm x 0.25 microm, 5% phenyl methyl siloxane), and the carrier gas is helium. The detection limits for ephedrine, pseudoephedrine, and TMP are 0.4 ng 0.7 ng, and 0.02 ng (signal-to-noise ratio of 3), respectively. The reproducibility of the total procedure is proved to be acceptable (RSD < 2%), and the recoveries are above 93%.
Journal of chromatographic science 09/2001; 39(9):370-4. · 0.88 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A method for the simultaneous separation and determination of the active constituents and three sugars in the roots of Gastrodia elata Blume (GE), which is used as a famous Chinese traditional herbal medicine, by gas chromatography-mass spectrometry is established. The samples are acetylated with pyridine-acetic anhydride. The contents of 4-hydroxybenzaldehyde, 4-hydroxybenzyl alcohol (HA), fructose, glucose, 4-(beta-D-glucopyranosyloxy)-benzyl alcohol (GA), and sucrose in GE are 0.004%, 0.03%, 1.36%, 1.12%, 1.97%, and 4.25%, respectively, and the detection limits are 1.5, 3.0, 11.0, 5.0, 33.0, and 35.0 pg, respectively. The contents of HA and GA in the urine and brain of a mouse are also determined. This method is simple, reliable, and quick for the simultaneous determination of the active constituents and sugars in GE.
Journal of chromatographic science 07/2001; 39(6):251-4. · 0.88 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A non-suppressed conductivity detection ion chromatographic method using a weakly acidic cation-exchange column (Tosoh TSKgel OApak-A) was developed for the simultaneous separation and determination of common inorganic anions (Cl-, NO3- and SO4(2-)) and cations (Na+, NH4+, K+, Mg2+ and Ca2+). A satisfactory separation of these anions and cations on the weakly acidic cation-exchange column was achieved in 25 min by elution with a mixture of 1.6 mmol L-1 pyridine-2,6-dicarboxylic acid and 8.0 mmol L-1 18-crown-6 at flow rate of 1.0 mL min-1. On this weakly acidic cation-exchange resin, anions were retained by an ion-exclusion mechanism and cations by a cation-exchange mechanism. The linear range of the peak area calibration curves for all analytes were up to two orders of magnitude. The detection limits calculated at S/N = 3 ranged from 0.25 to 1.9 mumol L-1 for anions and cations. The ion-exclusion chromatography-cation-exchange chromatography method developed in this work was successfully applied to the simultaneous determination of major inorganic anions and cations in rainwater, tap water and snow water samples.
The Analyst 06/2001; 126(5):567-70. · 4.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A high performance liquid chromatographic method with ethylenediamine dynamically modified silica column and evaporative light-scattering detection (ELSD) was developed for the direct determination of trehalose in transgenic tobacco extracts. The separation column (Zorbax Rx-SIL, 4.6 mm i.d. x 250 mm, 5 microns, Hewlett-Packard, USA) modified by ethylenediamine and a guard column (Zorbax Rx-SIL, 4.6 mm i.d. x 12.5 mm, 5 microns) were used. The mobile phase was a mixture of acetonitrile-water(2.6:1, V/V) containing 0.03% ethylenediamine. Regression equations revealed the linear relationships (r = 0.996-0.999) between the concentrations and peak areas of carbohydrates detected by ELSD. The detection limits of ELSD (S/N = 3:1) were 10 mg/L, 20 mg/L, 10 mg/L and 10 mg/L for fructose, glucose, sucrose and trehalose, respectively.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 06/2001; 19(3):226-9.
-
[show abstract]
[hide abstract]
ABSTRACT: A sensitive and reliable high performance liquid chromatographic method(HPLC) has been developed for the first time for the simultaneous determination of the active ingredients of ephedrine alkaloids and 2,3,5,6-tetramethyl pyrazine (TMP) in Ephedra herba crude drug and two Chinese traditional medicines (Xiao-er qingfeiwan and Lu-si kewan). The HPLC assay was performed on a reversed phase C18 column (Nova-Pak C18, 3.9 mm i.d. x 150 mm) by using methanol-0.02 mol/L KH2PO4-acetic acid-triethyl amine (4:96:0.2:0.01, V/V) as mobile phase for the ephedrine alkaloids analysis and methanol-H2O-acetic acid (35:65:0.5, V/V) as mobile phase for TMP analysis. Regression equations revealed the linear relationships (correlation coefficients: 0.991-0.998) between the peak area of each constituent (E, PE, NE, NPE, TMP) and its concentration. The detection limits for E, PE, NE, NPE and TMP were 0.4 mg/L, 0.1 mg/L, 0.03 mg/L, 0.02 mg/L and 0.03 mg/L, respectively, and the recoveries ranged between 92%-103%. The contents of E, PE, NE, NPE, TMP in Ephedra herba, traditional medicine Xiao-er qingfeiwan and Lu-si kewan were determined respectively. The relative standard deviations (RSD) of the contents ranged between 1.1%-3%.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 04/2001; 19(2):161-3.
-
[show abstract]
[hide abstract]
ABSTRACT: A high-performance liquid chromatographic method with a dynamically modified amino column and evaporative light-scattering detector (ELSD) was established for the direct analysis of the carbohydrates in some drinks. A separation column (Zorbax Rx-SIL, 250 mm x 4.6 mm I.D., 5 microm, Hewlett-Packard, USA) which was modified by ethylenediamine and a guard column (Zorbax Rx-SIL, 12.5 mm x 4.6 mm I.D., 5 microm) were used. The mobile phase was a mixture of water-acetonitrile (1:2.6, v/v) containing 0.03% (v/v) ethylenediamine. Regression equations revealed linear relationship (correlation coefficients=0.996-0.999) between the mass of carbohydrates injected and the carbohydrates peak areas detected by ELSD. The detection limits of ELSD (S/N=3) were between 0.2 and 1.2 microg for different carbohydrates. This method is simple and sensitive.
Journal of Chromatography 01/2001; 904(1):113-7. · 4.53 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: An easy, rapid and sensitive method for the determination of ferulic acid(FA) in Chuanxiong extracts, animal (mouse) serum and cerebrospinal fluid by RP-HPLC has been developed. The FA was separated on an ODS column, Nova-Pak C18(3.9 mm i.d. x 150 mm) and detected at the wavelength of 320 nm. The mobile phase was methanol-water-acetic acid (35:65:0.5, V/V), with a flow rate of 0.8 mL/min. The detection limit of FA was 1.7 micrograms/L(S/N = 3) and the calibration curve was linear within the range of 0.85 mg/L-4.00 mg/L(r = 0.99904, n = 6). The mean recovery from animal serum and cerebrospinal was 95%-102%.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 12/2000; 18(6):518-20.
-
[show abstract]
[hide abstract]
ABSTRACT: The theory, principles of operation and theoretical investigation of evaporative light-scattering detector (ELSD) are reviewed with 45 references. The applications of ELSD in HPLC on lipids, surfactants, pharmaceutical compounds and others are introduced.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 10/2000; 18(5):398-401.
-
[show abstract]
[hide abstract]
ABSTRACT: A reversed-phase HPLC method for the separation and determination of the two flavonoids: quercetin and kaempferol is described. The column was 25 cm x 4.6 mm i.d., packed with Zorbax SB-C18(5 microns). The mobile phase was a mixture of MeOH-H2O (60:40, V/V). The flow rate was 0.7 mL/min. UV detection was performed at 360 nm. External standard was used and the calibration curves showed good linearity over the range of 6.0-100 mg/L, r = 0.9995-0.9998, and detection limits were 3.3-6.2 mg/L. The recoveries were 96.0% and 97.3% for quercetin and kaempferol respectively. The relative standard deviations of the method were 2.1%-4.5%. The method is simple, fast, sensitive and accurate and can be applied to the analysis of quercetin and kaempferol. It provides a scientific basis for industrial production and quality control of Jinjuan liquor preparations for clinical uses.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 04/2000; 18(2):167-9.
-
[show abstract]
[hide abstract]
ABSTRACT: A reversed-phase high performance liquid chromatographic (RP-HPLC) method for the determination of the tetramethylpyrazine(TMP) in Chuanxiong extract, the animal(mouse) serum and cerebrospinal fluid has been developed. The TMP was separated on an ODS column Zorbax SB-C18(4.6 mm i.d. x 250 mm, 5 microns) at room temperature and detected by using UV detector at 270 nm. The mobile phase was methanol-water (50:50, V/V) containing 0.2 mmol/L of NH4H2PO4 flowing at a rate of 0.8 mL/min and 20 microL samples were injected. The detection limit of TMP was 1 mg/L and the calibration curve is linear between 5 and 500 mg/L with a correlation coefficient (r) of 0.999. The recovery of TMP ranged 98%-103%. The extract of Chuanxiong and pretreated serum and cerebrospinal fluid sample are stable for a week at room temperature.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 02/2000; 18(1):46-8.
-
[show abstract]
[hide abstract]
ABSTRACT: A review is presented about the chromatographic analysis of the polyphenols. Some of the chromatographic methods such as plate chromatography, gas chromatography, reversed-phase high performance liquid chromatography and some new chromatographic methods are introduced.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 02/2000; 18(1):35-8.
