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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Biological tissue

Classification: Biological tissue

Citations 33

"Slow Ultrafiltration For Continuous In Vivo Sampling: Application For Glucose And Lactate In Man"
Anal. Chim. Acta 1999 Volume 379, Issue 3 Pages 327-335
Renger G. Tiessen, Wilhelmina A. Kaptein, Kor Venema and Jakob Korf

Abstract: Background: An ultrafiltration (UF) technique was developed for continuous subcutaneous (s.c.) sampling and online analysis of absolute glucose and lactate concentrations in tissue. The relation between subcutaneous and blood concentrations was studied in men, because a subcutaneous monitoring device would put patients on less risks than an intravascular device. Methods: Ultrafiltrates were withdrawn continuously at a flow rate of 50-100 nl/min from a hollow fiber probe to measure glucose in the abdominal subcutis. Six healthy volunteers underwent an oral glucose tolerance test. In order to detect glucose and lactate in the same sample, a splitter was placed between the online flow injection valve and the parallel enzymatic conversion and electrochemical detection cells. Findings: Subcutaneous glucose concentrations were in steady state on the average 1.06 mM lower. They rose delayed and blunted as compared to blood levels. We demonstrated the ability of simultaneous lactate and glucose measurements in vivo (n=2). Interpretation: UF makes continuous monitoring of absolute extracellular concentrations in tissue possible. We interpret the deviations of subcutaneous measurements from intravascular levels in this way that the subcutis is a kinetic compartment not directly and exclusively linked to blood. The observed differences with blood suggest that diabetes management may demand intravascular monitoring. UF combined with analysis of glucose and lactate in the same sample offers the opportunity to study pathophysiology inside tissues.
Glucose Lactose Electrochemical analysis Process monitoring Immobilized enzyme

"Interfacial Enzyme Partitioning As A Tool For Constructing Biosensors"
Acta Aliment. 1999 Volume 28, Issue 4 Pages 329-338
N. Adányi, Szamos, J., M. Váradi

Abstract: To explore new possibilities of enzyme immobilization, we investigated bioactive layers prepared by a new procedure based on three-phase partitioning (TPP) of proteins. By this method a third phase or midlayer as a protein layer can be developed at the interface of a protein system containing two phases (organic solvent/aqueous salt solution). Proteins of meat origin partitioned together with bioselective material (e.g. an enzyme) after centrifugation resulted in excellent bioactive layers. In the newly developed sensor, glucose oxidase was immobilized in a layer, which was fixed on the surface of a platinum ring electrode. The biosensor was built in a flow injection analyzer (FIA) system, where the hydrogen peroxide generated during the enzymatic reactions was determined by an amperometric cell. The parameters for biochemical and electrochemical reactions (ion concentration and pH of buffer, flow rate) were optimized. The linear range of analysis by the newly developed sensor was from 0.5 to 10 mmol L-1 glucose. The biosensor could be used for more than 300 analysis.
Glucose Amperometry Sensor Enzyme Partition coefficients

"Determination Of Lead By Continuous-flow Hydride Generation And Atomic Absorption Spectrometry. Comparison Of Malic Acid - Dichromate, Nitric Acid - Hydrogen Peroxide And Nitric Acid - Peroxodisulfate Reaction Matrices In Combination With Sodium Tetrahydr"
Anal. Chim. Acta 1982 Volume 143, Issue 1 Pages 229-236
Kazuo Jin, Mitsuhiko Taga

Abstract: A continuous-flow hydride generator is combined with a heated quartz tube atomizer atomic absorption spectrometer system for the trace determination of lead. Malic acid K2Cr2O7, HNO3-H2O2 and HNO3-(NH4)2S2O3 are all effective for plumbane generation by means of sodium tetrahydroborate. The relative merits of these systems are investigated in terms of sensitivity, efficiency of plumbane generation and interferences. The sensitivities (0.0044 absorbance) obtained under the recommended conditions for the three systems are 3.2, 1.7 and 1.1 ng Pb mL-1, respectively, whereas plumbane generation efficiencies are 33%, 47% and>80%, respectively, for 1 µg Pb mL-1. Silver, Au, Cu and Cd interfere seriously in all reaction systems. A dithizone extraction and back-extraction method is utilized to eliminate interfering ions, followed by reduction of the resulting solution in the peroxodisulphate system. The proposed method is applied to water samples and NBS 1566 oyster tissue.
Lead Spectrophotometry

"Determination Of Phosphorus In Biological Tissues By Aluminum Block Digestion And Flow Injection Spectrophotometry"
Anal. Chim. Acta 1988 Volume 209, Issue 1 Pages 299-302
W. Maher, D. Lambert, J. Furlonger and P. Cullen

Abstract: The sample (0.1 g dry wt.) was digested with concentrated HNO3 (5 ml) at room temperature for 12 h and then with HClO4 (0.5 ml) with heating just until fuming, and the solution was diluted to 25 mL with water. The P was determined at 413 nm as the molybdovanadophosphate complex by using the flow injection system described by Royset (Ibid., 1985, 178, 217). The response was rectilinear up to 5 µg mL-1 (200 µL injection) and the limit of detection was 0.3 µg mL-1. Recoveries were 96% and the coefficient of variation (n = 10) for 1 and 25 µg mL-1 of P in standards taken through the entire procedure were 0.7 and 0.4%, respectively. Matrix interference was negligible. The results for seven standard reference materials were in agreement with certified values.
Phosphorus Clinical analysis Spectrophotometry Interferences Online digestion Reference material Tecator

"Time-based Device Used For The Determination Of Tin By Hydride-generation Flow Injection Atomic Absorption Techniques"
Anal. Chim. Acta 1995 Volume 308, Issue 1-3 Pages 339-348
M. Burguera, J. L. Burguera, C. Rivas, P. Carrero, R. Brunetto and M. Gallignani

Abstract: A time-based device (TBD) was used in conjunction with a flow injection hydride-generation AAS for the determination of Sn in biological materials. Biological materials were mineralized with HNO3/HClO4 and the resulting digests with an acidity of 0.5-2 M were used for the analysis. Two holding coils were filled with sample (2 ml) and 2 mL of 0.2% NaBH4 solution using the TBD. An Ar stream (50 ml/min) was used to displace these liquids through a reaction coil into the gas-phase separator (GPS). The flow was merged with an Ar stream (400 ml/min) immediately before entering the GPS. The gas phase was swept from the GPS to an electrically heated quartz tube at 800°C located in the AAS. Sn was determined at 224.6 nm. The calibration graph was linear for 10^-500 ng Sn and the detection limit was 5 ng for a 2 mL sample volume. RSD (n = 10) for the determination of 10 and 100 ng of Sn were 4.8 and 2.6%, respectively. The recovery of 10 ng of Sn from spiked biological tissue digests was >95%. The sampling frequency as 60 samples/h.
Tin Spectrophotometry Phase separator

"Photokinetic Determination Of Riboflavin And Riboflavin 5'-phosphate Using Flow Injection Analysis And Chemiluminescence Detection"
Analyst 1994 Volume 119, Issue 8 Pages 1825-1828
Tomás Pérez-Ruiz, Carmen Martínez-Lozano, Antonio Sanz and Virginia Tomás

Abstract: In a photolysis cell were placed 2 mL of 0.1 M phosphate buffer of pH 6, 1 mL of 0.1 M EDTA, 1 mL of 1.8 µM-iron(III) ammonium sulfate, 1 mL of 0.5 mM H2O2 and an appropriate volume of sample solution to yield a final riboflavin or riboflavin 5'-phosphate concentration of 0.1-5 µM. The solution was diluted to 10 mL with water and irradiated for 60 s at 25°C. A 35 µL portion of the photolysed solution was injected into a carrier stream (1.7 ml/min) of 1 M phosphate buffer of pH 12 and mixed with a reagent stream (1.7 ml/min) containing 0.1 mM luminol and 3 µM-haematin. The mixture was transported to a flow cell and the light emitted from the chemiluminescence reaction was measured. Diagrams of the photolysis cell and flow injection manifold used are given. The calibration graph was linear from 0.1-3 µM-riboflavin and riboflavin 5'-phosphate. RSD (n = 10) were 0.9-1.3%. The method was applied to animal tissues, foods and pharmaceuticals.
Chemiluminescence Kinetic Photochemistry

"Thermospray - Micro-atomizer Interface For The Determination Of Trace Cadmium And Cadmium Metallothioneins In Biological Samples With Flow Injection - And High Performance Liquid Chromatography - Atomic Absorption Spectrometry"
Anal. Chem. 1992 Volume 64, Issue 24 Pages 3197-3201
K. A. High, Richard Azani, A. F. Fazekas, Z. A. Chee, and J. S. Blais

Abstract: A description is given of a micro-atomization interface (made from quartz tubes) which is fuelled by hydrogen and can operate with 100% aqueous mobile phases used in HPLC. The system was optimized for the detection of Cd (total and bound soluble) in mussels and animal tissues, using flow injection AAS, or for the determination of metallothionein-bound Cd (isoforms I and II) in horse kidney, using HPLC - AAS. The detection limit obtained for Cd in the flow injection mode was ~2.2 orders of magnitude lower than that obtained with a conventional flame AAS detector, and 27-fold lower than that obtained by a thermospray-enhanced flame AAS system . Similar detection limits were obtained for the determination of metallothionein-bound Cd in the HPLC - AAS mode. A flexible thermospray-microatomization interface providing a high signal/noise ratio for flow injection atomic absorption spectrometry (AAS) and HPLC-AAS was designed and optimized for the determination of soluble Cd and Cd-metallothioneins (MTs). The interface, built from inexpensive quartz tubes, Swagelok fittings and thermoelectric wires, comprised 4 compartments: (1) a thermospray inlet; (2) a premixing tube in which the vaporized mobile phase was homogeneously mixed with preheated H; (3) a combustion chamber in which the fuel/sample mixture was mixed with O and pyrolyzed; and (4) a quartz tube (vapors retainer) mounted in the AAS analysis beam. This approach proved to more efficient than conventional flame AAS detection, due to the fact that the H/O flame (1900-2000°C), which pyrolysis mol. interferents to transparent CO2 and water vapors, is positioned remotely from the AAS optical beam. In this configuration, spectral interferences which are usually observed in flame and graphite furnace atomization were essentially eliminated. In flow injection (FI) mode, the response to Cd was linear from the limit of detection (71 pg) to 6 ng. The interface was optimized for the FI anal. of centrifuged mussel extracts, before and after ultrafiltration of the bound-Cd fraction on a 1000 MW cutoff membrane. During FI analyzes of these crude samples, matrix effect reduced the sensitivity by 13.2%, requiring calibration by standards addition Nonspecific absorption signal was not observed In HPLC-AAS mode, matrix effects in Cd-MTs chromatography bands were negligible. Cd-MTs from horse kidneys and mussels were determined with estimated limits of detection of 10^-40 ng (as protein).
Cadmium HPLC Spectrophotometry Optimization Interface Speciation Interferences

"Continuous-flow System For Measurement Of Calcium Ion Activities In The Fast Kinetic Mode"
Anal. Biochem. 1981 Volume 115, Issue 1 Pages 1-6
Hubert Affolter and Ernesto Carafoli

Abstract: A continuous-flow system, suitable for the fast kinetic measurement of changes in Ca2+ ion activity with specific electrodes, is described. Provided that the ionic strength of the measuring medium is at least 20 m, the system has a time resolution of 2 ms and a detection limit of 0.2 Ca2+. As an example of a possible biochemical application, some measurements of the initial rate of Ca2+ uptake by lobster muscle sarcoplasmic reticulum are presented.
Calcium Electrode Kinetic Activity

"High-sampling-rate Automated Continuous-flow Fluorimetric Technique For Analysis Of Nanogram Levels Of Histamine In Biological Samples"
Anal. Biochem. 1983 Volume 133, Issue 1 Pages 16-29
B. Lebel

Abstract: The method is based on that of Shore et al. (J. Pharmacol. Exp. Ther., 1959, 127, 182), automated to allow 60 analyzes in 1 h. Flow schemes, one with and the other without dialysis, are presented. Histamine is caused to react with phthalaldehyde, and the fluorescence of the product is measured at 450 nm (excitation at 360 nm); peak heights and baseline corrections are calculated by a computerized system. The limit of detection is 25 pg, and the rectilinear calibration range is 0 to 5 µg mL-1 of histamine. The method has been applied to whole blood, tissues and cell cultures.
Histamine Fluorescence Dialysis

"Determination Of Acetylcholine And Choline By Flow Injection With Immobilized Enzymes And Fluorimetric Or Luminometric Detection"
Anal. Biochem. 1989 Volume 176, Issue 2 Pages 221-227
Jan Rícný, Jilí Coupek and Stanislav Tucek

Abstract: Acetylcholine and choline were determined in solution and tissue extracts by a continuous-flow system with a sequence of enzyme reactors containing immobilized acetylcholinesterase, choline oxidase and peroxidase. Additional reactors with immobilized choline oxidase and catalase were used to remove choline and choline-generated H2O2 from samples when acetylcholine was being determined. Acetylcholinesterase, choline oxidase and catalase were immobilized on Separon HEMA E and peroxidase was immobilized on Separon HEMA (for fluorimetric detection) or on a coiled glass capillary or on controlled-pore glass beads (for luminometric detection). Detection was by measuring fluorescence generated from the reaction of H2O2 with 3-(4-hydroxyphenyl)propionic acid in presence of peroxidase, or measuring luminescence generated from the reaction of H2O2 with luminol in presence of peroxidase. Calibration graphs were rectilinear up to 100 pmol of acetylcholine with fluorescence detection. Detection limits were 10 or 25 pmol of acetylcholine with the coiled-capillary peroxidase or controlled-pore-glass peroxidase columns, respectively, with luminometric detection, and 0.2 pmol with fluorimetric detection.
Acetylcholine Choline Luminescence Fluorescence Immobilized enzyme Catalysis Controlled pore glass Glass beads Detection limit Column

"High Performance Liquid Chromatographic Analysis Of Phospholipids From Different Sources With Combined Fluorescence And Ultraviolet Detection"
Anal. Biochem. 1994 Volume 220, Issue 1 Pages 172-180
Bernhard W., Linck M., Creutzburg H., Postle A. D., Arning A., Martincarrera I. and Sewing K. F.

Abstract: Phospholipids (PL) were dissolved in CHCl3/methanol (1:4), mixed with N-monomethylphosphatidylethanolamine (200-300 µM, internal standard, prep. described) and analyzed by HPLC on a column (5 cm x 4.6 mm i.d.) of Schambeck Nucleosil 5 NH2 (5 µm) with a similar guard column (1 cm x 4.6 mm i.d.) coupled to a second column (17.5 cm x 4.6 mm i.d.) of the same material via a switch valve enabling the second column to be bypassed for elution of the acidic PL. The columns were operated at 50°C with acetonitrile/methanol/H2O/50% aqueous methylphosphonic acid (146:50:3:0.06) adjusted to pH 6.3 with 25% aq NH4OH as mobile phase (1 ml/min) and detection at 205 nm. Post-column derivatization was performed with 250 µL of Brij 35, 50 mg of NaN3 and 150 µL of diphenylhexatriene (3 mM in THF) in 1 l of water (4.5 ml/min) in Teflon tubing (200 cm x 0.8 mm i.d.) at 50°C, for fluorescence detection at 460 nm (excitation at 340 nm). For fluorescence detection the calibration graphs were linear for up to 60 nmol of phosphatidylcholine (PC) species and up to 100 nmol of other PL; the detection limits were 0.5-2 nmol. The UV absorption differed among PL classes.
Phospholipids HPLC Fluorescence Spectrophotometry

"An Automatic Continuous-flow Aminopeptidase Detector And Its Applications"
Anal. Biochem. 1996 Volume 242, Issue 2 Pages 271-273
Koon-Sea Hui and Maria Hui

Abstract: Biological tissue samples were homogenized at 4°C with 50 mM Bicine hydrochloride buffer containing 0.2 mM DTT and centrifuged at 100 000 g for 1 h before being injected on to a Mono-Q column (5 cm x 5 mm i.d.) for elution with a gradient (1 ml/min) of NaCl in Bicine buffer. The eluate was mixed with buffer and added to 0.2 mM aminoacyl-2-naphthylamide (substrate) in buffer for fluorimetric detection at 250 nm (excitation) and 389 nm (emission). The calibration graph was linear for 10^-800 µg of puromycin-sensitive aminopeptidase, with a detection limit of 100 pg and an assay variation of the effect of phosphatase inhibitors on the enzyme preparation and the application of the assay is discussed.
Aminopeptidases LC Fluorescence Post-column derivatization Interferences

"Individual And Simultaneous Determination Of Zinc And Cadmium In Biological Tissues By Flow Injection Stripping Voltammetric Analysis"
Electroanalysis 1994 Volume 6, Issue 9 Pages 764-768
A. Izquierdo, M. D. Luque De Castro, M. Valcárcel

Abstract: Lyophilized samples were digested as described by Bond et al. (cf. Anal. Chem., 1982, 54, 2318) and analyzed by the cited technique. Detection was performed using a polarograph connected to a wall jet cell with a vitreous working electrode, Ag/AgCl (3 M KCl) reference electrode and Au auxiliary electrode. Before analysis, the working electrode surface was conditioned with a stream of 0.1 µM-Hg(II) (0.2 ml/min) for the deposition of a Hg film at a working electrode potential of -1.0 V vs. Ag/AgCl for 20 min, followed by 0.0 V for 2 min. The stream was then switched to a carrier of 1 M acetate buffer solution (0.2 ml/min) of pH 4.5 into which the sample (600 µL) was injected and a deposition potential of -1.0 V was applied to the working electrode. Three minutes after injection, the flow was halted, and 5 s later a positive differential pulse scan from -1.0-0.0 V (repetition time 0.4 s; pulse amplitude 50 mV; scan rate 40 mV/s) was applied. Detection limits were 0.8 nM and 2 nM for Cd and Zn, respectively, corresponding determination limits were 1 nM and 5 nM. RSD were 1.57% (Cd) and 5.6% (Zn). Results for reference materials agreed with certified values. No interference caused by the formation of intermetallic compounds was detected.
Cadmium Zinc Voltammetry Electrode Electrode Interferences Reference material

"Post-column Derivatization Procedure For Colorimetric Analysis Of Tissue Cannabinoids Separated By High Performance Liquid Chromatography"
J. Chromatogr. A 1981 Volume 205, Issue 2 Pages 303-323
Henry K. Borys and Ralph Karler

Abstract: A new method for quantitating cannabidiol (CBD) and ?9-tetrahyrocannabinol (THC) in mouse plasma and brain involves (1) the separation of CBD and THC from their majro metabolites by the use of isocratic, revrsed-phase high-performance liquid chromatography (HPLC), and (2) the on-line reaction of the cannabinoids with Fast Blue Salt B (FBB) as teh former elute from the column; the colored cannabinoid-FBB derivatives are then detected at 490 nm in a spectrophotometer with a sensitivity of less than 50 ng. In addition to this HPLC-FBB analytical procedure, a method for extracting CBD and THC from brain and plasma is described, and selected examples illustrate the procedure's application to the analysis of CBd and THC in mouse plasma and brain samples taken from animals injected with these two cannabinoids.
Cannabinoids HPLC Spectrophotometry Post-column derivatization

"Determination Of Free Trimethyllysine In Plasma And Tissue Specimens By High Performance Liquid Chromatography"
J. Chromatogr. B 1984 Volume 306, Issue 1 Pages 79-87
Alan T. Davis, Stephen T. Ingalls and Charles L. Hoppel

Abstract: Trimethyl-lysine and triethyl-lysine (internal standard) are extracted from acid-deproteinized plasma or the acid-soluble fractions of tissue homogenates by sorption on a mixed-bed ion-exchange column [Dowex 1-X8 (OH-) and 50W-X8 (NH4+)] and elution with aqueous 1 M NH3 and water. The compounds are transferred into HCl for HPLC on a Radial-Pak C18 cartridge (10 cm x 5 mm) with a guard column of Co:Pell ODS and with aqueous 30% acetonitrile, containing 50 mM Na dodecyl sulfate and 50 mM NaH2PO4, as mobile phase; fluorimetric detection involves post-column derivatization with phthalaldehyde - 2-mercaptoethanol. The calibration graph is rectilinear from 0.5 to 4 µM; the detection limit is 25 pmol injected.
6-N,N,N-Trimethyllysine HPLC Ion exchange Fluorescence Post-column derivatization

"Sensitive And Selective Determination Of Picogram Amounts Of Ciprofloxacin And Its Metabolites In Biological Samples Using High Performance Liquid Chromatography And Photothermal Post-column Derivatization"
J. Chromatogr. B 1987 Volume 416, Issue 1 Pages 321-330
H. Scholl, K. Schmidt and B. Weber

Abstract: Liquid samples are diluted with 0.033 M H3PO4; faeces are homogenized with water, extracted with CHCl2 - propan-2-ol - 0.3 M H3PO4 (1:5:4) and centrifuged; tissue homogenates are extracted with concentrated HClO4 and concentrated H3PO4 in aqueous 50% methanol. Extracts or sample solution are analyzed on a column (25 cm x 4 mm) of Nucleosil 120-5 C18 (5 µm) at 40°C with 4% tetrabutylammonium hydrogen sulfate in aqueous 7 to 10 or 25 to 30% acetonitrile as mobile phase (2 mL min-1). Detection is by fluorescence at 445 nm (excitation at 278 nm). For some metabolites, post-column derivatization by successive thermolysis and photolysis is required and the reactor used is described. Limits of detection were between 0.2 and 2.2 ng mL-1 of ciprofloxacin and its metabolites. Recoveries were from 71.3 to 116.7% and coefficient of variation (n = 35 to 50) were from 1.7 to 2.7%.
Ciprofloxacin HPLC Fluorescence Heated reaction Post-column derivatization

"High Performance Liquid Chromatographic Determination Of Clenbuterol And Cimaterol Using Post-column Derivatization"
J. Chromatogr. B 1991 Volume 564, Issue 2 Pages 537-549
Dirk Courtheyn*, Carlo Desaever and Roland Verhe

Abstract: Animal tissues, faeces and feeding-stuffs were extracted with dilute 0.5 M HCl saturated with ethyl acetate; the resulting extracts or liquid samples, e.g., urine, plasma, blood and bile were purified on Chem Elut CE 120 columns and eluted with toluene - CH2Cl2. The eluate was mixed with 0.1 M HCl, ultrasonicated and centrifuged before a portion of the mixture was analyzed by HPLC on a column (15 cm x 4.6 mm) of Nova-Pak C18 (4 µm) with 25 mM sodium dodecyl sulfate and 0.02 M anhydrous acetic acid buffer of pH 3.5 containing 1 M NaOH - acetonitrile (53:47) as mobile phase (1.3 mL min-1). The eluate was derivatized with use of three reagents (details given) before the absorbance was measured at 537 and 493 nm for cimaterol and clenbuterol, respectively. Detection limits for liquid and solid samples were 0.1 ng mL-1 and 0.2 ng g-1, respectively. Results agreed well with those obtained by high performance TLC and GC - MS.
Cimaterol Clenbuterol HPLC Spectrophotometry Buffer Column Detection limit pH Post-column derivatization

"Determination Of Metals In Biofluids And Tissues Sample Preparation Methods For Atomic Spectroscopic Techniques"
Spectrochim. Acta B 1996 Volume 51, Issue 3 Pages 291-319
Kunnath S. Subramanian

Abstract: Several sample preparation methods unique to each instrumental technique exist for the elemental analysis of biological specimens, but no review or book has dealt with them. The present review is an attempt to fill this void and focuses on sample preparation methods unique to atomic and X-ray spectroscopic techniques. The techniques covered are: flame and electrothermal AAS, inductively coupled plasma atomic emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS) and X-ray fluorescence spectrometry (XRF) since these are most commonly used in trace element analysis of biological materials. The intent is not to present the procedural details for the various tissues or elements, but rather to highlight the methods which are unique to each instrument. The bibliography accompanying this review should aid the analytical chemist in his/her search for the detailed preparation protocols.
Metals Spectrophotometry HPLC Mass spectrometry Spectrophotometry Review Preconcentration

"Automated Determination Of Vitamin C In Food Stuffs And Biological Materials"
Analusis 1989 Volume 17, Issue 9 Pages 519-525
Bourgeois, C.F.;Chartois, H.R.;Coustans, M.F.;George, P.R.

Abstract: The sample (e.g., organ tissue, blood plasma, foodstuff) is extracted with aqueous 5% metaphosphoric acid and the extract is placed in an automated apparatus. Ascorbic acid is oxidized by iodine to dehyroascorbic acid, which is coupled with 4,5-dimethyl-1,2-phenylenediamine to give a fluorescent quinoxaline derivative. This compound is extracted into isoamyl alcohol, back-extracted into a basic aqueous solution where it forms a hydrophilic salt, and the fluorescence is measured against that of a borate buffer. Compared with conventional fluorimetric methods the measurement is carried out in an almost pure solution, thus minimizing matrix interferences. The mean recovery was 98.7%, the coefficient of variation was 1.4% and the sensitivity was 20 ng mL-1.
Ascorbic acid Fluorescence Sample preparation Automation Redox Extraction Buffer Sensitivity Apparatus Interferences

"New Convenient Method For Microdetermination Of Hydroxyproline By Flow Injection Analysis"
Chem. Pharm. Bull. 1986 Volume 34, Issue 6 Pages 2649-2652
Uchida, K.;Shibata, T.;Tomoda, M.;Saito, S.;Inayama, S.

Abstract: The flow injection analysis modification of the conventional KISO method is based on the color reaction of pyrrole, produced from hydroxyproline(I) by oxidation and decarboxylation, with Ehrlich reagent. The hydrolysate solution (~20 µg of I in 0.5 to 0.75 ml) prepared from the tissue sample was injected into a stream of the buffer (KCl 18.0 g l-1, H3BO3 4.95 g l-1, and KOH, pH 8.7) and oxidant solution (chloramine T, 0.1408 g l-1); after oxidation, the sample was decarboxylated at 100°C. The resulting stream was mixed 1:1 with Ehrlich reagent, and the absorbance of the colored product was measured 560 nm. Response was rectilinearly related to I concentration. up to 80 µg mL-1. The time required for one measurement was ~3.5 min, and the coefficient of variation at 100 µg mL-1 was 1.05% (n = 24).
Hydroxyproline Spectrophotometry Heated reaction

"Flow Injection Analysis"
Daxue Huaxue 1991 Volume 6, Issue 1 Pages 24-28
Xu, S.

Abstract: Review: Chemical analysis of the positive solution of automation is an important development direction of modern analytical chemistry from the 1960s in the field of clinical chemistry analysis is used widely. Continuous flow Skeggs proposed colorimetric analysis system was the fastest growing, one of the most widely used technique. 1974 Ruzicka by injection injector and the abolition of Skeggs system introduces air bubbles in the pipeline approach, creating a flow injection analysis (Flow Injection Analysis, referred to as FIA), the continuous flow analysis to a new level, this new technology is essential characterized by analyzing speed, high precision, wide adaptability, and can greatly save the sample and reagents. General analysis sample rate of up to 100-200 times/hour, analysis accuracy of 1%, the relative standard deviation.
Drugs Review

"Improved Methods For Determination Of Fluoride In Biological Materials"
Fluoride 1986 Volume 19, Issue 1 Pages 22-25
K Seifert, B Dominok, GW Dominok

Abstract: Fluoride is separated from cartilage or aortic tissues without ashing by an adaptation of the method of Yoshida et al. (Anal. Abstr., 1979, 37, 6B109). The reaction takes place in a closed apparatus comprising a 100 mL flask in series with two gas bubblers, each containing 25 mL of 0.1 M NaOH. The sample, 50 mL of water and two drops of hexamethyldisiloxane are placed in the flask, and 40 mL of concentrated H2SO4 is added to the sample through a dropping funnel. The trimethylsilanol(I) produced reacts with the F- to form fluorotrimethylsilane(II), which is swept by N (50 mL min-1) to the bubblers. II is converted by the alkali back into I, which is extracted into toluene before measurement of the F- so liberated in 0.45 M HClO4 medium with an I--selective electrode. Urine is analyzed directly for F- in 0.5 M HClO4 medium containing 0.001% of Triton X-100 by using two F--selective electrodes in a flow injection system. The latter method was applied to urine of persons drinking fluoridated water or occupationally exposed to F. The former method was applied to tissues from adults and infants, and the results are reported.
Fluoride Electrode Electrode Sample preparation Surfactant Triton X

"Comments On The Standard Fluorometric Determination Of Riboflavin In Foods And Biological Tissues"
Food Chem. 1992 Volume 43, Issue 1 Pages 79-82
L. F. Russell* and Joseph T. Vanderslice

Abstract: The vitamin B-2 content of foods has historically been determined as total riboflavin (TRF), and the most common method of TRF analysis has been the AOAC standard fluorometric procedure. A modification of this method to permit the use of flow injection analysis (FIA) is reported here. a number of foods were analyzed and the results generally agreed with the published values. However, the standard method was not found to be universally suitable for all types of samples.
Riboflavine Fluorescence Method comparison Standard method

"Liquid Chromatographic Determination Of Six Sulfonamide Residues In Animal Tissues Using Post-column Derivatization"
J. AOAC Int. 1993 Volume 76, Issue 5 Pages 966-976
Bui, L.V.

Abstract: Homogenized kidney or liver mixed with methyl-p-aminobenzoate (internal standard) and acetone/CHCl3 was shaken, centrifuged and filtered; the filtrate was evaporated. The residue was shaken with acetonitrile; the acetonitrile layer was collected and the residue was centrifuged with hexane and acetonitrile. The hexane layer was extracted with acetonitrile and centrifuged. The acetonitrile extract was evaporated to dryness (residue A). The hexane layer was centrifuged if necessary, mixed with 15% trichloroacetic acid with shaking and centrifuged. The aqueous layer was mixed with residue A in hexane with shaking and centrifuged. Saturated aqueous sodium citrate solution was added and, after thorough mixing, the solution was analyzed on a column (30 cm x 3.9 mm) of µBondapak C18 (10 µm) with a pre-column (1.5 cm x 3.2 mm) of RP-18 (7 µm) with gradient elution (1.5 ml/min) with aqueous 1% acetic acid/aqeous 80% acetonitrile (details given). p-Dimethylaminobenzaldehyde in acetonitrile/aqueous 5% trichloroacetic acid (3:7) was merged (0.5 ml/min) with the eluate and passed through coiled tubing (7 m x 0.25 mm) before detection at 450 nm. Recoveries were 70-104%; RSD were 2-10%. The detection limit was 20 µg/dg.
Sulfonamides HPLC Spectrophotometry Post-column derivatization

"Continuous-flow Vapor Generation For Inductively Coupled Argon Plasma Spectrometric Analysis. 1. Selenium"
J. AOAC Int. 1990 Volume 73, Issue 3 Pages 404-410
Tracy ML, Möller G.

Abstract: Sample (~1.5 g of solid or ~10 mL of liquid) is wet ashed with HNO3, H2SO4 and HClO4 at ~310°C; details are presented for treatment of different samples. The digest is cooled to room temp., 5 M HCl is added and the solution is diluted. In a simple continuous-flow manifold, sample solution is mixed with 12 M HCl and then 0.6% NaBH4 solution The H2Se produced is separated off by a standard pneumatic neublizer, and Se is determined by ICP-AES at 196.090 nm. The detection limit is 0.4 µg l-1, or 4 µg kg-1 for a nominal 1-g sample. The calibration graph is rectilinear for 4 mg kg-1. The method has been applied to biological tissues and fluids and to water. Results show good agreement with those by AAS and NAA.
Selenium Spectrophotometry Dilution Nebulizer Detection limit Calibration

"Automatic Simultaneous Determination Of Copper And Lead In Biological Samples By Flow Injection/stripping Voltammetric Analysis"
J. Autom. Methods Manag. Chem. 1993 Volume 15, Issue 4 Pages 121-125
ANDRÉS IZQUIERDO, M. D. LUQUE DE CASTRO, and MIGUEL VALCÁRCEL

Abstract: An automated continuous-flow injection stripping-voltammetric method is presented for the simultaneous determination of Cu and Pb in biological tissue. Lyophilized liver and kidney were digested according to the procedure of Adelojou and Bond (Anal. Chem., 1985, 57, 1728) and a portion of the final solution was injected into a carrier stream (0.2 ml/min) of 1 M sodium acetate/acetic acid buffer solution (pH 4.5). After 3 min, at a deposition potential of -1.0 V applied to the pre-conditioned (details given) vitreous working electrode, the carrier refills the flow-cell and the flow is stopped for 5 s. A positive differential pulse scan is applied to the working electrode from -1.0 to 0.0 V (repetition time 0.4 s; amplitude 50 mV; scan rate 40 mV/s). Measurements were carried out vs. Ag/AgCl with an Au auxiliary electrode. The oxidation intensity current data was acquired by a computer and the signals were compared with those obtained using calibration standards. Calibration graphs were rectilinear for 0.64-64.0 and 2.1-62.2 ng/ml of Cu and Pb, respectively. The RSD values obtained were 4%. The results obtained compared well with certified values.
Copper Lead Voltammetry Reference material

"Evaluation Of Flow Injection Sample To Standard Addition Method For The Inductively Coupled Plasma Mass Spectrometric Determination Of Aluminum In Biological Tissues"
J. Mass Spectrom. 1996 Volume 31, Issue 4 Pages 427-432
A. G. Coedo*, M. T. Dorado, J. Ruiz, M. Escudero, J. C. Rubio

Abstract: Tissues were minced, dried and powdered. Portions (0.5 g) were oxidized with 4 mL HNO3 in a microwave apparatus, with a 7-step heating programme. The solution was evaporated almost to dryness, mixed with a solution containing 1 µg Sc(III) (internal standard to compensate for plasma and ion signal instability) and diluted to 25 mL with 0.1% HNO3. Portions (0.5 ml) of this solution were injected into the carrier (2.8 ml/min) containing an Al(III) standard of 20 ng/ml and 40 ng/nl of Sc(III) in 0.1% HNO3 and this was followed by the injection of 0.5 mL of a digestion blank. The injection valve was located a few cm away from the cross-flow nebulizer and the ions 27Al and 45Sc were measured. The sample concentration then corresponded to the difference between the signals for the sample (maximum) and the blank (minimum). The method has the advantages of requiring less sample, being quicker and minimizing salt deposition on the sample and skimmer cones. Results for reference materials were similar to those obtained by conventional standard additions. Recovery of 0.5-10 ppm Al(III) was close to 100%. The detection limit was 10 ppb.
Aluminum(III) Mass spectrometry Sample preparation Calibration Reference material Standard additions calibration

"Liquid Chromatography - Luminescence Methods"
Life Sci. 1987 Volume 41, Issue 7 Pages 901-904
Kazuko Mori

Abstract: Catecholamines in alumina extracts of urine or plasma or in tissue homogenates were separated by HPLC on TSK-gel ODS-1207 with KH2PO4 - acetonitrile - EDTA as mobile phase, pre- or post-column derivatization and fluorimetric detection. After post-column reaction based on trihydroxyindole formation with Fe(CN)63- as oxidant, the fluorescence of adrenaline and noradrenaline derivatives was measured at 520 nm (excitation at 410 nm). Dopamine could not, however, be detected in plasma by this method or by an alternative technique with electrochemical detection. The method could easily be automated, including a pre-column system. By pre-column derivatization with 1,2-diphenylethylenediamine (after cleanup on a cation-exchange column), dopamine and the other catecholamines could be determined in plasma; the detection limit was ~2 fmol. Fluorescence was measured at 480 nm (excitation at 350 nm).
Catecholamines Adrenaline Noradrenaline HPLC Fluorescence Sample preparation Post-column derivatization Pre-column derivatization

"Flame Atomic Absorption Spectrometry With Flow Injection Sample Introduction For The Determination Of Heavy Metals In Biological Materials"
Wiss. Z. Univ. Halle 1987 Volume 36, Issue 1 Pages 3-15
Friese, K.;Matschiner, H.

Abstract: The cited method was applied in the determination of Mn in hair, Cr in biological tissues and Pb in blood. The coefficient of variation were 5.8, 8.1 and 1.7% for 1.9 ppm of Mn, 0.07 ppm of Cr and 4.6 µM-Pb, respectively.
Chromium Metals, heavy Lead Manganese Spectrophotometry Theory

"Clenbuterol Residue Analysis By HPLC - HPTLC In Urine And Animal Tissues"
Z. Lebensm. Unters. Forsch. 1989 Volume 189, Issue 2 Pages 128-131
Jean-Marie Degroodt, Brigitte Wyhowski de Bukanski, Hedwig Beernaert and Dirk Courtheyn

Abstract: Tissue samples were digested with subtilisin A at 55°C for 1 h in 0.2 M Tris buffer of pH 8 containing 0.1 M CaCl2. The mixture was centrifuged, the solid was washed with more buffer and the supernatant solution were combined. This solution, or a diluted urine sample, was adjusted to pH 10 with NaOH and applied to a Chem Elut CE 1020 column; after 15 min, clenbuterol was eluted with hexane (three portions) and extracted from the eluate into 0.01 M HCl. The resulting solution (100 µL) was analyzed by HPLC on a column (25 cm x 4 mm) of LiChrosorb RP-8 (10 µm), with 0.01 M Na acetate (pH 3.5) - acetonitrile (3:7) as mobile phase (1 mL min-1) and post-column derivatization by adding NaNO2 - HCl (cooled in ice), ammonium sulfamate and N-(1-naphthyl)ethylenediamine with product determination at 500 nm. The calibration range for clenbuterol was 5 to 100 ng mL-1 and the detection limit was 2 ng. Recoveries ranged from 70 to 73% for tissues and from 85 to 90% for urine. The results were confirmed by high performance TLC.
Clenbuterol HPLC Buffer Dilution Column Post-column derivatization Calibration Detection limit

"Determination Of Germanium In Some Plants And Animals"
Z. Naturforsch. C 1990 Volume 45, Issue 11-12 Pages 1250-1251
Sigeki Hara, Nanao Hayashi, Sigeo Hirano, Xi-Ning Zhong, Shigejiro Yasuda, and Hisashi Komae

Abstract: The Ge contents of plants and animals were investigated by a wet ashing procedure by hydride generation and inductively coupled plasma atomic emission spectrometry with flow injection. The analytical results obtained indicated that Ge contents widely vary in plant and animal kingdoms in the range of 8-302 ppb.
Germanium Sample preparation Spectrophotometry PPB

"Determination Of Chromium And Manganese Traces In Biological Material By Flame AAS With Flow Injection Sample Introduction"
Zentralbl. Pharm., Pharmakother. Lab. Diagn. 1988 Volume 127, Issue 6 Pages 420-421
Friese, K.

Abstract: The combination of flow injection analysis and flame AAS is briefly discussed. For the cited application, samples were digested in closed PTFE vessels to give a final volume of 0.5 to 2 mL. Human hair samples (25 to 50 mg) were analyzed for Mn and gave day-to-day coefficient of variation of 20% (at 0.2 ppm) and 5% (at 2 ppm). Various biological tissues were analyzed for Cr. The accuracy of the procedure was demonstrated by analysis of four IAEA standard reference materials.
Chromium Manganese Spectrophotometry Reference material