University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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Chinese

Classification: Pharmaceutical -> herbal -> chinese

Citations 10

"Flow Injection Analysis Of Tannic Acid With Inhibited Chemiluminescent Detection"
Anal. Chim. Acta 1998 Volume 362, Issue 2-3 Pages 151-155
Hua Cui*, Qiang Li, Rong Meng, Huazhang Zhao and Caixia He

Abstract: Tannic acid was found to inhibit chemiluminescence of the luminol-H2O2 reaction catalyzed by Cu2+. The mechanism of inhibition was studied by chemiluminescent spectra, UV-visible spectra and variation of reaction conditions. A flow injection method was developed for the determination of tannic acid based on the inhibition of the chemiluminescence of the luminol-H2O2-Cu2+ system by tannic acid. The method is simple, selective and sensitive with a detection limit of 9 x 10^-9 mol/l. It is effective to determine tannic acid at 7 x 10^-8-1 x 10^-5 mol/l. The variation coefficient of eleven determination for 6 x 10^-7 mol/l tannic acid is 2.5%. The method was successfully applied to the determination of tannic acid in real Chinese gall and hop pellets samples.
Tannic acid Chemiluminescence Indirect

"Flow Injection - Electrochemical Hydride-generation Technique For Atomic Absorption Spectrometry"
J. Anal. At. Spectrom. 1992 Volume 7, Issue 2 Pages 287-292
Yuehe Lin, Xiaoru Wang, Dongxing Yuan, Pengyuan Yang, Benli Huang and Zhixia Zhuang

Abstract: A flow injection - electrothermal hydride generation technique for AAS has been developed in order to avoid the use of sodium tetrahydroborate, which is capable of introducing contamination. A specially designed thin-layer electrolytic flow cell (diagram given) for hydride generation was used in a normal flow injection system coupled to an electrically heated T-tube atomizer for atomic absorption measurements. The sample was injected into the electrolyte carrier stream flowing to the electrolytic cell, where hydride-forming elements were reduced to gaseous hydrides. The effects of factors such as the eletrode material, electrolyte, current density and carrier stream flow rate, on the rate of formation of the hydride and interferences were studied. The technique was used to determine of As in mangrove leaves, Se in traditional Chinese medicines and Sb in polyester film. The detection limits were 0.45, 0.62 and 0.92 ng mL-1 of As, Se and Sb, respectively.
Arsenic Selenium Antimony Spectrophotometry Electrochemical product generation Volatile generation Interferences Volatile generation

"A Combined Flow Injection Chemiluminescent Method For The Measurement Of Radical Scavenging Activity"
Anal. Biochem. 1998 Volume 264, Issue 2 Pages 291-293
Hong-Yeob Choi, Jin-Hyang Song and Dong-Ki Park

Abstract: The authors report a simple, rapid and reproducible flow injection-chemiluminescent method for radical scavenging activity. Chemiluminescence intensity is decreased by the presence of scavengers and the reduction is proportional to the concentration. and ability of scavengers. The flow injection-chemiluminescent method represents high reproducibility and anal. speed. The authors achieved relative standard deviation of 1.88%, and each run in less than 25 s. The present technique proves to be inexpensive, fast, and reliable. This flow injection-chemiluminescent technique could be applied as an alternative method for the measurement of the radical scavenging abilities of biological components. (c) 1998 Academic Press.
Gallic acid Chemiluminescence Indirect

"Application Of Flow Injection Hydride-generation Graphite-furnace Atomic Absorption Spectrometry. 2. Determination Of Trace Germanium"
Fenxi Huaxue 1994 Volume 22, Issue 6 Pages 586-589
Ma, Y.P.;Han, Y.Q.;Ariguli, R.

Abstract: Sample (0.1-0.5 g) was digested with HNO3 or HNO3, HClO4 and HF, and then diluted with water to 25 mL. Using a self-developed flow injection hydride-generation graphite-furnace AAS system, the solution (500 µL) was introduced and carried by a stream of water at 3.2 ml/min to react with 20% Na3PO4 at 5 ml/min in a reaction tube (40 cm long) then with 0.3 M H3PO4 at 3.2 ml/min in a reactor (120 cm long) before reacting with 0.5% KBH4 at 3.2 ml/min. The generated hydride was transferred with Ar as carrier gas at 14 ml/min to an automatic sampler (coated by treating with PdCl2 and KBH4) then to the AAS instrument equipped with a pyrolytically-coated graphite tube. Drying, pre-concentration and atomization temperature were 120°C, 750°C for 35 s and 2200°C, respectively. Detection limit was 1.3 pg. Recovery was 99.5-10%. Little interference was observed. Results were compared with those of the GF and hydride-generation flame methods. Sampling frequency was 30 runs per h. The method was utilized for assay of soil and Chinese herbal drugs including Rhodiola kirilouic and Lycium chinense.
Germanium Spectrophotometry Sample preparation Interferences Method comparison Volatile generation Preconcentration Volatile generation

"Coupled Flow Injection And High Performance Capillary Electrophoresis In The Analysis Of Traditional Chinese Medicine Cortex Magnoliae Officinalis"
Fenxi Shiyanshi 1998 Volume 17, Issue 2 Pages 1-4
Shen, Q.;Fang, Z.L.

Abstract: A FI-HPCE method was developed for traditional Chinese medicines. A new flow injection sample introduction interface was proposed for capillary electrophoresis. Using the FI-HPCE system, buffer concentration, pH, voltage and percentage of methanol were optimized to sep. magnolol and honokiol from other constituents in Cortex Magnolial Officinalis and their medicinal preparations The sample throughput was 10/h, the relative standard deviation at 138 µg/mL magnolol was 2.1% (n=6) and the recoveries were in the range of 96%~102.9%.
Magnolol Honokiol Electrophoresis Interface pH Buffer Optimization

"Microwave Digestion-continual Flow Injection Cold Atom Absorption In Determination Of Trace Hg In Traditional Chinese Medicine"
Guangpu Shiyanshi 1998 Volume 15, Issue 4 Pages 46-50
WU Shuhuai, CAI Yijuan

Abstract: This experiment established a method of digesting traditional Chinese medicine drug with microwave sample preparation system and using continual flow injection-cold atom absorption to determine trace Hg in traditional Chinese medicine drug. The method studied the influence of two different mixed acid digestion systems (HNO3-H2O2 and HNO3-HClO4-H2SO4) and the influence of digestion time and pressure. The detection limit is 0.15 ng/mL, recoveries are between 91%-116%, RSD is 4.9%.
Mercury Spectrophotometry Sample preparation Optimization

"Determination Of Trace Manganese(II) With Online Flow Injection Solvent-extraction Preconcentration Flame Atomic Absorption Spectrometry"
Guangpuxue Yu Guangpu Fenxi 1994 Volume 14, Issue 1 Pages 91-94
Chi, X.Z.;Zhou, J.

Abstract: Sample solution was prepared by mixing sample with acetic acid/sodium acetate buffer solution of pH 6 and ethanolic 1.2% ammonium pyrrolidinedithiocarbamate (I). A FIA system (diagram given) comprised of pumps to deliver sample solution (4 ml/min) and methyl isobutyl ketone (2 ml/min) to an extraction flask, the absorbance of the organic extract containing Mn-I complex was measured automatically by AAS with use of an AA-670 atomic absorption spectrophotometer with lamp current of 8 mA, acetylene flow rate of 2.5 l/min, air flow rate of 10 l/min, burner height of 3 mm and slit width of 0.19 nm. The calibration graph was linear from 0.5-5 µg/ml. The detection limit was 0.076 µg/ml. Recoveries ranged from 94-102%. The method was used to determine trace Mn in hair, surface water and traditional Chinese medicine.
Manganese(II) Spectrophotometry Sample preparation Solvent extraction Complexation Organic phase detection Preconcentration MIBK

"Construction And Application Of All-solid-state Aconitine Electrochemical Detector In Flow Injection Analysis"
Yaoxue Xuebao 1992 Volume 27, Issue 4 Pages 294-298
Liu WZ, Zuo AL

Abstract: The cited detector exhibits Nernstian response for aconite (I) and its derivatives, with a slope of 56 mV per decade from 30 µM to 30 mM at pH 2 to 7. Direct potentiometry for I in Aconitum kusnezoffi and A. carmichaeli showed recoveries of 96.8 to 98.5%, with coefficient of variation of 1.8 to 3.5%. The detector can be applied to determine I and its derivatives in samples by flow injection analysis. An all-solid-state electrochemical detector used in flow injection analysis for determining aconitine (I), mesaconitine (II) and hypaconitine (III) was constructed (diagram given). For determination of the aconitines in Aconitum kusnezoffii Reichb, Aconitum carmichaeli Debx. and xiaohuoluo pills, sample (10 g) was extracted with 50 mL of 7 M NH3 and 100 mL of ethyl ether, the ether layer was evaporated to dryness and the residue was dissolved in 5 mL each of 0.1 M HCl and 1 M phosphate buffer solution (pH 6.5) and water to 50 mL. A 400 µL portion of the solution was injected into the flow system. Nernstian response was observed for 10 mM to 30 µM I, II or III and the electrode was stable for 6 h. The mean recoveries of I to III were 98.5, 98.3 and 96.8%, respectively; corresponding coefficient of variation were 1.8, 2.4 and 3.5%. Results agreed with those obtained by spectrophotometry (Ch. P. 1990). A new kind of all-solid-state electrochemical detector for very toxic alkaloids such as aconitine, mesaconitine and hypaconitine was studied. It exhibits Nernstian response for these alkaloids with a slope of 56 mV/decade over the concentration range of 3 x 10^-5 to 1 x 10^-2 mol/L at pH 2-7 under the flow condition. Direct potentiometry for the determination of aconitine in Aconitum kusnezoffii Reichb., Aconitum carmichaeli Debx. and Xiaohuoluowan showed average recoveries of 98.5, 98.3 and 96.8% and relative standard deviations of 1.8, 2.4 and 3.5%, respectively. It can be used for the determination of very toxic alkaloids in the above mentioned samples by flow injection analysis It also can be used for the study of the hydrolytic kinetics of aconitine.
Aconitine Mesaconitine Hypaconitine Potentiometry Kinetic Method comparison

"Flow Injection Analysis Of Tetracyclines Using Inhibited Ru(bpy)32+/tripropylamine Electrochemiluminescence System"
Luminescence 2005 Volume 20, Issue 1 Pages 8-15
Yong-Qiang Pang, Hua Cui*, Hai-Song Zheng, Guo-Hui Wan, Li-Juan Liu, Xiao-Feng Yu

Abstract: Tetracyclines (TCs) were found to strongly inhibit the electrochemiluminescence (ECL) from the Ru(bpy)32+-tripropylamine system when a working Pt electrode was maintained at 1.05 V (vs. Ag/AgCl) in pH 8.0 carbonate buffer solution. On this basis, a flow injection (FI) procedure with inhibited electrochemiluminescence detection has been developed for the determination of tetracycline (TC) and oxytetracycline (OTC). Under the optimized condition, the linear ranges of 2.0 x 10^-8-1.0 x 10^-5 and 1.0 x 10^-8-1.0 x 10^-5 g/mL and the detection limits of 4.0 x 10^-9 and 3.8 x 10^-9 g/mL were obtained for TC and OTC, respectively. The relative standard deviations (RSD) were 0.68% and 1.18% for 5.0 x 10^-7 g/mL TC and OTC (n = 13), respectively. The method showed higher sensitivity than most of the reported methods. It was successfully applied to the determination of tetracycline in a Chinese proprietary medicine, Tetracyclini and Cortisone Eye Ointment, and the residues of tetracycline in honey products. The inhibition mechanism has been proposed due to an energy transfer between electrogenerated Ru(bpy)32+* and benzoquinone derivatives at the electrode surface.
Tetracycline Chemiluminescence Electrode Optimization Sensitivity

"Separation And Determination Of Four Active Anthraquinones In Chinese Herbal Preparations By Flow Injection-capillary Electrophoresis"
Electrophoresis 2005 Volume 26, Issue 15 Pages 2999-3006
Lihong Liu, Liuyin Fan, Hongli Chen, Xingguo Chen, Professor, Zhide Hu

Abstract: A simple, rapid, and accurate method for the separation and determination of physcion, chrysophanol, aloe-emodin, and emodin in Rhubarb, Juemingzi, and Chinese herbal preparations was developed by combination of flow injection-capillary zone electrophoresis for the first time. The analysis was carried out using an unmodified fused-silica capillary (75 mm x 50 m ID x 375 m OD, effective separation length of 48 mm) and direct ultraviolet detection at 254 nm. By a series of optimization, the sample solvent consisted of NaOH (100 mmol/L) and ACN (1:1 v/v), and a running buffer composed of 15 mmol/L sodium borate - 12.5 mmol/L sodium dihydrogen phosphate - 42% v/v ACN (pH 10.1) was applied for the separation of the four anthraquinones. The separation was rapid and highly reproducible, with complete resolution of all four compounds within 6 min. The sample throughput rate could reach up to 12 per h. The repeatability (defined as relative standard deviation) was 4.45, 4.44, 4.34, 0.61% with peak height evaluation and 1.62, 0.89, 2.49, 2.19% with peak area evaluation for physcion, chrysophanol, aloe-emodin, and emodin, respectively.
Physcion Chrysophanol Aloe-emodin Emodin Spectrophotometry Electrophoresis Interface