University of North Florida
Browse the Citations

Contact Info

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

View Stuart Chalk's profile on LinkedIn

Biological fluid

Classification: Biological fluid

Citations 33

"Analytical Applications Of Chemiluminogenic Reactions"
Anal. Chim. Acta 2000 Volume 413, Issue 1-2 Pages 175-186
Leonidas P. Palilis and Antony C. Calokerinos

Abstract: Chemiluminescence (CL) and bioluminescence (BL) are natural phenomena which have attracted the attention of mankind since the evolution of life on the earth. The various mechanisms of formation of cold light were explained during this century and CL was established as an analytical technique during the last few decades. The dramatic growth in the quality and quantity of analytical chemiluminometric methods came soon after the introduction of flow injection analysis into the area of CL and the development of successful flow cells. Hence, CL is now considered as a very sensitive analytical technique. A plethora of new chemiluminogenic reactions have been discovered by trial and error and successfully used analytically, but efforts to foresee which molecules participate in CL reactions are continuously made. Over the last few decades some general rules have been modulated and are briefly presented in this paper. A practical example is the CL generated during the action of potassium permanganate on trimetazidine (1-(2,3,4-trimethoxybenzyl)piperazine) which is presented in this paper. The discovery is important since analytical procedures for determining trimetazidine are very limited in number and new methodologies are required for assaying the drug in biological fluids. The analytical procedure which was finally developed allows the determination of trimetazidine within the linear range of 5-1000 ng mL-1. Less known CL techniques which offer great advantages over other analytical methods are also presented. The beginning of the millennium will find CL as a powerful tool for sensitive measurements after miniaturized separation systems and as field analyzer.s. Emphasis should be given to the thorough investigation of the mechanism of the reactions which generate radiation to allow full control of the capabilities of the technique.
Trimetazidine Chemiluminescence Review

"Flow Injection Analysis Of Pharmaceuticals"
J. Anal. Chem. 2001 Volume 56, Issue 4 Pages 313-323
M. I. Evgen'ev, S. Yu. Garmonov, L. Sh. Shakirova

Abstract: The current state and outlooks of the development of the fow-injection analysis of medicinal substances in pharmaceuticals and biological fluids are considered. The role of chemical, photochemical and enzymatic reactions of derivatization in the flow injection determination of pharmaceuticals is outlined. The role of detection methods in improving the selectivity and sensitivity of the flow injection analysis of pharmaceuticals and expanding its possibilities in pharmaceutical analysis is considered.
Drugs Chemiluminescence Amperometry Fluorescence Stopped-flow Immobilized enzyme Extraction Review

"On-line Detection Of Nitric Oxide Generated By The Enzymatic Action Of Nitric Oxide Synthase On L-arginine Using A Flow Injection Manifold And Chemiluminescence Detection"
Anal. Chim. Acta 2000 Volume 410, Issue 1-2 Pages 167-175
Nicholaos P. Evmiridis and Dachun Yao

Abstract: A study of the catalytic activity of nitric oxide synthase (NOS) on the conversion of arginine to NO and citrulline is made. The target of this report is to establish a method for on-line monitoring the reaction process using the chemiluminescence (CL) generated from NO in the luminol-H2O2 system. The NOS-catalytic activity is found to decrease with time on stream in a flow enzymatic reactor but the activity is recovered by proper treatment with restoring solution. For on-line detection of NO formed in-situ, using how injection with CL detection, the response is found more sensitive if a pulsed sampling procedure is employed rather than a continuous one; the sample in the former is small and is injected periodically between regeneration cycles. The optimal pH, temperature and flow rate were determined. The calibration graph under optimal conditions is linear for arginine concentration; the relative standard deviation is <1% and the effect of interferents present in biological fluids is found to be much different to those for the native enzyme in solution. The immobilized NOS-reactor was long lived.
Nitric oxide l-arginine Chemiluminescence Immobilized enzyme Optimization Process monitoring

"Automatic Enzymatic Determination Of Glucose With A Potentiometric Sulfur Dioxide Probe"
Anal. Chim. Acta 1981 Volume 125, Issue 1 Pages 55-64
P. W. Alexander and P. Seegopaul

Abstract: An automatic, continuous-flow system for the determination of glucose is reported, with a sulphur dioxide probe used as the sensor for an indicator reaction with hydrogensulphite. In the presence of glucose oxidase, glucose is selectively oxidized to produce hydrogen peroxide at a rate proportional to the glucose concentration. The oxidation of hydrogensulphite by the hydrogen peroxide is rapidly monitored by the probe at sampling rates as high as 90 samples per hour. Proteins and reducing substances, such as cysteine, uric acid and ascorbic acid interfere only in large amounts. The method is applicable to biological fluids without prior separation steps.
Glucose Clinical analysis Potentiometry Enzyme

"Studies Of Drug-protein Binding Interactions By Flow Injection Analysis With Fluorimetric Detection"
Anal. Chim. Acta 1983 Volume 145, Issue 1 Pages 109-116
G. L. Abdullahi, J. N. Miller, H. N. Sturley and J. W. Briges

Abstract: The applicability of single-channel and merging-zones flow injection systems with fluorimetric detection to the study of drug-protein binding interactions has been demonstrated. A study of the binding of the fluorescent probe 8-anilinonaphthalene-1-sulphonic acid (ANS) to human serum albumin by means of such systems gave results identical to those obtained by a static procedure, but the flow injection procedure was much more convenient. The flow injection methods were also used in pure albumin solution and in diluted serum to study the displacement of ANS by acidic drugs. The flow injection procedures were extended to investigate the binding of basic drugs to α1-acid glycoprotein. A recent fluorescence probe derived from propanolol permitted calculations of the number and strength of the binding sites on this protein for propanolol and other drugs.
Drugs Proteins Clinical analysis Fluorescence Enzyme Merging zones

"Carbon Electrode Sputtered With Palladium And Gold For The Amperometric Detection Of Hydrogen Peroxide"
Anal. Chim. Acta 1985 Volume 178, Issue 2 Pages 247-253
Lo Gorton

Abstract: By deposition of a 15-nm layer of Pd - Au (2:3) on the surface of a carbon electrode, the overvoltages for both the oxidation and reduction of H2O2 could be decreased by 0.8 V. When the resulting electrode was applied as a sensor in a single-channel flow injection system, calibration graphs were rectilinear between 0.1 µM and 5 mM H2O2. The modified electrodes were stable for months and could be especially useful where H2O2-producing oxidases are being used in the analysis of biological fluids.
Hydrogen peroxide Amperometry Electrode

"Determination Of Myo-inositol In A Flow Injection System With Immobilized Enzyme Reactors And Amperometric Detection"
Anal. Chim. Acta 1988 Volume 206, Issue 1-2 Pages 49-55
Bo Olsson, Gy&ouml;rgy Marko-Varga, Lo Gorton, Roger Appelqvist and Gillis Johansson

Abstract: myo-Inositol 2-dehydrogenase, lactate dehydrogenase and lactate oxidase are co-immobilized on porous glass and used in a packed-bed enzyme reactor. The myoinositol(I) in the biological fluid sample reacts to produce an equivalent amount of H2O2, which oxidizes ferrocyanide to ferrocyanide in a second reactor containing immobilized peroxidase. The ferrocyanide is then detected amperometrically at O mV vs. the SCE in a flow-through detector. The system responds rectilinearly to I concentration. from 1 to 300 µM. The max. throughput was 90 samples h-1, and the enzyme reactor was stable for 5 weeks.
Myo-inositol Amperometry Controlled pore glass Immobilized enzyme Merging zones

"Analysis Of Metabolites In Sweat As A Measure Of Physical Condition"
Anal. Chim. Acta 1994 Volume 289, Issue 1 Pages 27-34
Kohji Mitsubayashi, Masayasu Suzuki, Eiichi Tamiya and Isao Karube*

Abstract: Sweat collected from healthy volunteers after physical exercise or heating was analyzed for lactate, glucose, uric acid, Na+, chloride and ammonium using either amperometric biosensors or commercially available ISE. The biosensors were constructed from the Clark-type dissolved O2 sensor and an enzyme membrane containing the respective immobilized oxidase enzyme (lactate 2-monooxygenase, glucose oxidase or urate oxidase). The biosensors were mounted in a flow injection system and used with a 67 mM phosphate buffer carrier stream of pH 7 (0.86 ml/min) and at a potential of -700 mV vs. Ag/AgCl. Calibration graphs for lactate, glucose and uric acid were linear for 0.06-1.85 mM, 0.28-3.33 mM and 0.06-0.5 mM, respectively. For the ISE the linear ranges were 0.1-10 mM Na+, 0.01-10 mM chloride and 0.059-5.9 mM ammonium. The average concentration of lactate and ammonium ion in sweat induced by exhaustive exercise were 5.2- and 10.6-fold higher than those obtained for the analysis of heat induced sweat. The concentration of lactate was linearly related to the concentration of ammonium. The analysis of sweat for lactate and ammonium was an effective, non-invasive method for estimating physical condition.
Lactate Glucose Uric acid Sodium Chloride Ammonium Electrode Amperometry Sensor Electrode

"Immunosensing With Amperometric Detection, Using Galactosidase As Label And P-aminophenyl-galactopyranoside As Substrate"
Anal. Chim. Acta 1995 Volume 304, Issue 3 Pages 353-359
M&aacute;r M&aacute;ssen, Zheng Liu, Tetsuya Haruyama, Eiry Kobatake, Yoshihito Ikariyama and Masuo Aizawa*

Abstract: p-Aminophenyl---galactopyranoside (PAPG) was shown to be a suitable substrate for the amperometric detection of galactosidase activity at neutral pH. The application of this amplification system for immunoassay was demonstrated. The product of the enzyme reaction, p-aminophenol (PAP), was detected at 200 mV, vs. , by flow-injection analysis (FIA), with a 50 nM detection limit. PAPG was hydrolyzed more than 2.5 times faster than p-nitrophenyl---galactopyranoside, by the enzyme. Both PAP and PAPG were stable at pH 7. The galactosidase concentration could be measured down to a concentration of 100 fM, and mouse IgG could be assayed by sandwich immunoassay down to 700 fM. PAPG was found to be a promising reagent for heterogeneous systems, like the one described, and for homogeneous assays of biological fluids.
Enzyme, galactosidase Immunoassay Amperometry Enzyme Amplification reaction

"High Performance Liquid Chromatographic Determination Of Peptide Drugs In Biological Fluids By Means Of Pre- And Post-column Fluorescence Derivatization Techniques"
Anal. Chim. Acta 1997 Volume 352, Issue 1-3 Pages 61-69
Venkata K. Boppana* and Cynthia Miller-Stein

Abstract: Several high performance liquid chromatographic methods utilizing a variety of fluorescence derivatization schemes have been summarized both for the detection and routine quantitation of peptide drugs in biological fluids. The derivatization reactions have been carried out either in pre- or post-column modes with various commercially available reagents and targeted primarily at α- and ε-amino groups, guanidino group of arginine and sulfhydryl groups present in the peptide chain. These analytical methods are very robust and comparable to immunoassays in sensitivity and have been used for quantification of peptide analytes in various pharmacokinetic and toxicokinetic studies. This discussion also summarizes the derivatization schemes that have not been fully explored to date but may find utility in future for development of highly sensitive analytical methods for peptide analytes.
Peptides Drugs HPLC Fluorescence Post-column derivatization Pre-column derivatization

"Determination Of 5-hydroxytryptamine (serotonin) And Related Indoles By Flow Injection Analysis With Acidic Potassium Permanganate Chemiluminescence Detection"
Anal. Chim. Acta 1998 Volume 362, Issue 2-3 Pages 131-140
Neil W. Barnett*, Benjamin J. Hindson and Simon W. Lewis

Abstract: A simple, rapid and sensitive method for the determination of 5-hydroxytryptamine (serotonin), 5-hydroxytryptophan or 5-hydroxyindole-3-acetic acid, using flow injection analysis with acidic potassium permanganate chemiluminescence detection, is described. The log-log plots for 5-hydroxytryptamine, 5-hydroxytryptophan and 5-hydroxyindole-3-acetic acid gave equations of best fit, of y = -0.03x2+0.51x+6.15 (r2 = 0.9990), y = -0.05x2+0.35x+5.70 (r2 = 0.9995) and y = -0.04x2+0.49x+5.60 (r2 = 0.9999), respectively., where y is log (chemiluminescence emission response (mV)) and x is log (concentration. (M)). The log-log calibration functions for the three analytes approximated linearity in the concentration. range from 1 x 10^-8 to 1 x 10^-6 M, where the slopes of the log-log plots were within the range from 1.01 to 1.04. The precision (measured as relative standard deviation) for 5-hydroxytryptamine was 2.3% (n = 6 at 1 x 10^-7 M). The detection limits (signal-to-noise ratio = 3) were 2 x 10^-9 M, 3 x 10^-9 M and 1.5 x 10^-8 M for 5-hydroxytryptamine, 5-hydroxytryptophan and 5-hydroxyindole-3-acetic acid, respectively. Preliminary experiments using an extended range photomultiplier tube realized enhanced detection limits due to the wavelength of max. emission being centered around 670 nm rather than 610 nm as previously thought. (34 References)
5-Hydroxytryptamine Indoles 5-Hydroxytryptophan 5-Hydroxyindole-3-acetic acid Chemiluminescence Optimization Process monitoring

"Permanganate-based Chemiluminescence Analysis Of Cefadroxil Monohydrate In Pharmaceutical Samples And Biological Fluids Using Flow Injection"
Talanta 1998 Volume 47, Issue 2 Pages 471-478
Fatma A. Aly, Nawal A. Alarfaffj and Abdulrahman A. Alwarthan*

Abstract: A chemiluminescent method using flow injection is described for the determination of cefadroxil monohydrate. The method is based on the chemiluminescence reaction of cefadroxil with potassium permanganate in sulfuric acid, sensitized by quinine. The proposed procedure allows the determination of cefadroxil over the concentration. range 0.1-30 µg mL-1 with a detection limit of 0.05 µg mL-1 and a sample measurement frequency of 150 samples h-1. The method was successfully applied to the determination of cefadroxil in pharmaceutical preparations and biological fluids.
Cefadroxil Chemiluminescence

"Continuous-flow Analysis For Uric Acid In Biological Fluids, With Immobilized Uricase In A Closed-loop System"
Anal. Chem. 1980 Volume 52, Issue 14 Pages 2332-2338
Assaha Iob and Horacio A. Mottola

Abstract: Relatively inexpensive and/or stable enzymes can be directly used in solution for repetitive determinations in closed-flow systems. Important clinical determinations (e.g., uric acid in biological fluids), however, require enzymes that are not sufficiently stable and/or inexpensive to be used in solution for relatively long periods of time and at the high activity levels needed for success in unsegmented closed-flow systems. This paper reports on the chemical immobilization of uricase on controlled pore glass, certain characteristics of the immobilized enzyme preparation, and application of it as packing in mixing- delay coils for the determination of uric acid In biological fluids. Determinations can be performed at a 100 samples/h rate with satisfactory precision (24% RSD). The method was compared with a regularly used colorimetric procedure in the SMA 18/90 analyzer [correlation coefficient = 0.98 for 22 samples of human blood serum]. The immobilized enzyme preparation retains over 70 % of its initial activity after repetitive use for more than 10 months.
Uric acid Clinical analysis Spectrophotometry Closed loop Enzyme Immobilized enzyme

"Reversibly Immobilized Glucose Oxidase In The Amperometric Flow Injection Determination Of Glucose"
Anal. Chem. 1987 Volume 59, Issue 22 Pages 2688-2691
W. Uditha De Alwis, Brian S. Hill, Bruce I. Meiklejohn, and George S. Wilson

Abstract: Glucose oxidase(I) is reversibly immobilized by utilizing reaction sequences involving antibody - antigen reactions. In method A, I - anti-human IgG (goat) conjugate is passed through a packed-bed reactor in which human IgG is covalently immobilized. In method B, polyclonal goat anti-mouse IgG Fab' fragment immobilized on a support is used to reversibly immobilize a mouse monoclonal anti-I antibody that is used to immobilize the I. The reactors are coupled to a flow injection analysis system. After the immunological reaction, glucose is determined in biological fluids by amperometric monitoring of the H2O2 produced by the I-catalyzed reaction with O. The calibration graphs were rectilinear from 1.1 nmol to 11 µmol and from 0.11 nmol to 1.1 µmol for reactors A and B, respectively. The detection limits were 50 pmol (A) and 12 pmol (B). The precision of the H2O2 determination was >1%. On exhaustion, the reactors can be reloaded to within 3% of the original activity.
Glucose Amperometry Electrode Immobilized enzyme Reactor

"Flow Injection Analysis With Electrochemical Detection"
Fresenius J. Anal. Chem. 1988 Volume 329, Issue 6 Pages 691-697
K. Cammann

Abstract: Two combinations of flow injection analysis with electrochemical detection are discussed. The use of potentiometry with ion-selective electrodes is illustrated by the determination of NO3- alone and simultaneously with Na+, K+, Ca(II), HCO3- and Cl- in drinking water, of Al without a reference electrode, of SO2 in grape juices, and of glucose in biological fluids. The apparatus is described and the experimental conditions are given. A hanging-mercury-drop electrode (at 0 V vs. Ag - AgCl) was used for the amperometric detection of ascorbic acid in a buffer (pH 4.7) stream.
Aluminum Ascorbic acid Glucose Nitrate Sulfur dioxide Amperometry Electrode Electrode Potentiometry Interferences Review

"A Simple Procedure For The Chromatographic Analysis Of Nanoliter Samples"
Fresenius J. Anal. Chem. 1998 Volume 360, Issue 2 Pages 260-262
Rosanna Toniolo, Alan Valentino, G. Bontempelli, Gilberto Schiavon

Abstract: A simple method for the analysis of nanoliter droplets is proposed, which is profitable when larger samples cannot be collected as, for instance, in the case of several biological fluids and particularly in clinical chemistry a glass capillary associated to a micromanipulator is used to collect sub-microliter volumes which are partially transferred into transparent polymeric tubings with known internal diameters (120-178 µm), where the volumes sampled are measured by meniscus collimations with a collimator microscope at suitable magnification. Both ends of these tubings are preliminarily equipped with ferrules and fittings, so as to make them suitable for connection a the loop to a conventional high-pressure injection valve. The reliability of this procedure has been tested for the anal. of Na+, K+, and Ca2+ present in minute synthetic standard samples (10-200 nL) by a conventional ion-chromatography instrumentation. Relative standard deviations in peak area measurements (5-6%) are discussed in terms of the whole approximation affecting volume measurements, which depends on both the inconstancy of the inner diameter of the polymeric tubings employed and the uncertainty characterizing meniscus collimations. The proposed procedure can be easily extended to the determination of any organic or inorganic species present in very small samples, provided that their detection can be achieved by any chromatography approach or, more generally, by flow injection analysis.
Sodium Potassium Calcium Apparatus Droplet Small sample

"Determination Of Mercury By Inductively Coupled Plasma-mass Spectrometry"
Microchem. J. 1996 Volume 54, Issue 4 Pages 348-354
B. Passariello, M. Barbaro, S. Quaresima, A. Casciello and A. Marabini

Abstract: Mercury was determined in different liquid and solid (minerals and atmospheric particulates) environmental materials and biological fluids. Several different methods of digestion of solid samples were used (details given) and all gave satisfactory results. To the solution was added Rh as internal standard followed by HNO3. Instrumental detection was performed with a ICP-MS Sciex Elan spectrophotometer. Instrumental parameters are tabulated. The calibration graph was linear up to 10 µg/l and the detection limit was Results were compared with those from a flow injection MS technique.
Mercury Mass spectrometry Sample preparation

"Two-dimensional High Performance Liquid Chromatographic System For The Determination Of Enantiomeric Excess In Complex Amino-acid Mixtures. Single-amino-acid Analysis"
J. Chromatogr. A 1993 Volume 653, Issue 2 Pages 229-234
Arnaldo Dossena, Gianni Galaverna, Roberto Corradini and Rosangela Marchelli*

Abstract: Amino-acids occurring in biological fluids and foods were separated on a sulfonated poly(styrene-divinylbenzene) (6 µm; Li+ form) column (12 cm x 4.6 mm i.d.) operated at 45°C with LiCl/lithium citrate buffer solution as mobile phase. Each peak corresponding to an individual amino-acid was passed to a Spherisorb ODS-2 (3 µm) column (15 x 4.6 mm i.d.) operated at 25 or 35°C with an aqueous buffer solution containing chiral Cu(II) complexes (details given) as mobile phase (0.3-2 ml/min). Details of the chromatographic system and column-switching mechanism are presented. Post-column fluorogenic derivatization was carried out with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole for proline and hydroxyproline and with phthalaldehyde for the other amino-acids. Determination of D-amino-acids up to a D-to-(D + L) ratio of 0.1% in the nanomolar range was possible.
Amino Acids HPLC Post-column derivatization

"Automated Determination Of Amoxycillin In Biological Fluids By Column Switching In Ion-pair Reversed-phase Liquid Chromatographic Systems With Post-column Derivatization"
J. Chromatogr. B 1985 Volume 344, Issue 1 Pages 285-296
Jan Carlqvist and Douglas Westerlund

Abstract: Plasma was deproteinized with HClO4 and buffered with citrate - phosphate buffer solution (pH 5.4) - 1 M NaOH (11:4) before analysis. Urine was adjusted to pH 4.85 with citrate - phosphate buffer solution before analysis. The chromatographic system comprised a guard column (5 mm x 4 mm) of Spherisorb S5 ODS (5 µm) and two analytical columns (10 cm x 4.6 mm) of CP Microspher C18 (3 µm) separated by a switching valve. Amoxycillin(I) was isolated on the first column with a mobile phase (0.75 mL min-1) of 10 to 11% of methanol in phosphate buffer solution (pH 7.4) containing 1 mM Na hexyl sulfate, and the eluate fraction containing I was transferred to the second column; I was eluted with a mobile phase (1 mL min-1) of 30 to 35% of methanol in phosphate buffer solution (pH 7.4) containing 1 mM tetrahexylammonium hydrogen sulfate. The eluate was mixed with fluorescein in acetonitrile before fluorimetric detection at 470 nm (372.5-nm excitation). The detection limits for I in plasma and urine were 10 and 25 ng mL-1, respectively, and the calibration graph was rectilinear for 0.05 to 75.2 µg mL-1 of I in urine.
Amoxycillin HPLC Fluorescence Post-column derivatization

"Indirect Continuous Automatic Determination Of Pharmaceuticals By Atomic Absorption Spectroscopy"
J. Pharm. Biomed. Anal. 1990 Volume 8, Issue 8-12 Pages 655-661
M. Valc&aacute;rcel*, M. Gallego and R. Montero

Abstract: The implementation of continuous separation techniques such as precipitation, liquid-liquid and solid-liquid extraction in FIA manifolds coupled online with an atomic absorption spectrometer for the determination of active components (sulfonamides, local anaesthetics, amphetamines, benzodiazepines, chloramphenicol and methadone) in pharmaceuticals and biological fluids is systematically described. The basic features of the analytical methodologies described (sensitivity, selectivity, precision and rapidity) are also discussed and critically compared. The use is described of continuous separation techniques such as, precipitation, liquid - liquid and solid - liquid extraction in flow injection analysis manifolds coupled online to an AA spectrometer for the determination of active components in pharmaceuticals and biological fluids. Sulfonamides were pptd. with Cu standard solution (more selective) or Ag ions at pH 6 to 7, filtered and the filtrate was measured by AAS. Anaesthetics were pptd. with Co ions. Recoveries were quantitative. The continuous liquid-liquid extraction technique was based on the method described by Nord and Karlberg (Anal. Chim. Acta, 1981, 125, 199) and was applied in the determination of amphetamines and bromazepam. Solid-phase redox columns were used for those compounds with potentially reducible groups, e.g. sulfone, N-oxide groups. The basic features (sensitivity, selectivity, precision and rapidity) of the analytical methods described are discussed.
Bromazepam Amphetamines Anaesthetics Spectrophotometry Sample preparation Automation Precipitation Extraction pH Selectivity Sensitivity Filtration Reduction column Indirect

"Characterization Of N-substituted Polypyrrole Thin-film Electrode Having Immobilized Glucose Oxidase"
Sens. Actuat. B 1993 Volume 14, Issue 1-3 Pages 665-666
Mikito Yasuzawa, Nobuyuki Matsushita, Hiromu Satake and Akira Kunugi

Abstract: The glucose sensor was prepared by the electropolymerization of 1-pyrrole propionic acid (PPA) and/or 1-pyrrole propanol (PPO; details given). The electrode properties were examined by measuring the electrocurrent of H2O2 using a FIA system at 25°C with 0.1 M phosphate buffer of pH 7.4 (0.93 ml/min). The maximum response was achieved at 20 mC/cm2 and pH 7. The PPA film electrode had the highest sensitivity but the reproducibility was poor whilst the PPO film electrode was low in sensitivity but had good reproducibility. The electrode modified by PPA/PPO (1:1) gave good reproducibility and was very sensitive. Repetitive injections of 2.8 mM glucose gave an RSD of 2%. The effects of other electroactive species present in biological fluids were investigated at their physiological maximum concentration (5.6 mM); ascorbic and uric acids interfered strongly and this will have to be overcome for in vivo application of the biosensor.
Glucose Electrode Sensor Detector Interferences

"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

"Tandem Online Separations: An Alternative Sample Presentation In Atomic Spectrometry For Ultra-trace Analysis"
Acta Chim. Hung. 1991 Volume 128, Issue 4-5 Pages 551-558
Sanz Medel, A.;Menendez Garcia, A.;Fernandez, M.L.;Sanchez Uria, J.E.

Abstract: The coupling of continuous-separation - pre-concentration. devices with atomic spectrometers for ultra-trace elementary analysis is discussed. Simple systems are first outlined, including solid - liquid and liquid - liquid online flow injection extraction coupled with AAS or ICP-AES for Al determination in biological fluids, and continuous gas - liquid separation coupled with ICP-AES for As determination in steel and as an introduction device for S2- determination in a microwave plasma. Examples are then given of tandem configurations in which two different continuous separation units are combined in a single online configuration. A tandem online device based on continuous extraction combined with hydride generation and coupled with ICP-AES for direct As, Sb and I- determinations is described, as well as a continuous liquid - liquid extraction device coupled with ICP-AES or AAS for indirect I- determination. Results show that many sensitivity and selectivity limitations of ultra-trace analysis can be overcome by the use of tandem online separation techniques.
Aluminum Arsenic Spectrophotometry Spectrophotometry Sample preparation Extraction Preconcentration Ultratrace

"Determination Of Reduced Type Nicotinamide Adenine Dinucleotide By Flow Injection Analysis Using Immobilized Enzyme-voltammetry System"
Bunseki Kagaku 1984 Volume 33, Issue 6 Pages 310-314
Chow, T.;Yoshida, S.;Itoh, M.;Hirose, S.;Takeda, T.

Abstract: In the flow injection system described, a proton acceptor is reduced by dihydrolipoamide reductase (NAD+), immobilized on glass beads, with oxidation of NADH, and the reduced species is then oxidized and detected voltammetrically. Of three proton acceptors studied, Bindschedler's green(I) was the most suitable; 10 µM-I in 0.1 M phosphate buffer (pH 7.0 to 8.5) was used as carrier solution (0.5 mL min-1). The limit of detection was 1 pM-NADH at +0.04 V vs. silver - AgCl; this was ~100-fold more sensitive than direct determination. In the determination of NADH in biological fluids, bilirubin, haemoglobin and ascorbic acid did not interfere.
Nicotinamide adenine dinucleotide reduced Nicotinamide adenine dinucleotide oxidized Clinical analysis Voltammetry Immobilized enzyme Glass beads Interferences

"Low Results For Inorganic Phosphorus With The SMAC Continuous-flow Analyser"
Clin. Chem. 1981 Volume 27, Issue 3 Pages 490-492
EA Robertson, RJ Elin and E Johnson

Abstract: Serum inorganic phosphorus concentrations as measured with the SMAC are lower than those found with other methods. To resolve this problem we analyzed patients' specimens and performed analytical recovery studies with four different systems (SMAC, AutoAnalyzer II, aca, and the Fiske-- SubbaRow method). With the SMAC, results for patients' specimens are significantly lower (p less than 0.0001) than with any of the other three methods. The SMAC recovered only about 87% of the added inorganic phosphorus. The value assigned to SMAC Reference I for inorganic phosphorus was 0.876 of the value obtained when the material was analyzed by the reference method. Thus there is a significant systematic error in the SMAC method for inorganic phosphorus determination, attributable to an erroneous inorganic phosphorus concentration assigned the SMAC calibration material by the supplier (Technicon).
Phosphorus Clinical analysis

"Therapeutic Agents Affecting Amino-acid Chromatograms"
Clin. Chem. 1989 Volume 35, Issue 9 Pages 1999-2000
MA Brewster and W Starrett

Abstract: Biological fluids were deproteinized and I was adjusted before centrifugal filtration (Amicon Centrifree filter; 20 min). The filtrate was analyzed for amino-acids by HPLC on a column (15 cm x 3 mm) of cation-exchange resin (7 µm; Li+ form) at 45°C with Li citrate buffers (pH 2.75 and 7.5) as gradient eluents (0.3 mL min-1), post-column derivatization with phthalaldehyde and fluorescence detection at 425 nm (excitation at 334 nm). Iohexol and trometamol were eluted near or on the tyrosine peak, phenylpropanolamine was co-eluted with tyramine in the following chromatogram and amikacin gave a post-arginine peak which carried over on to the subsequent 2 to 3 chromatograms.
Iohexol Trometamol Tyrosine Phenylpropanolamine Tyramine Amikacin Arginine HPLC Fluorescence Clinical analysis Post-column derivatization

"Automated Fluorimetric Determination Of Creatine Using Flow Injection Analysis"
J. Chem. Soc. Pak. 1989 Volume 11, Issue 1 Pages 32-36
Masoom, M.

Abstract: The sample was analyzed by computer-controlled stopped-flow flow injection analysis in water as carrier stream (2.5 mL min-1), with mixing with aqueous ethanolic 10% ninhydrin and aqueous ethanolic 10% KOH and fluorimetric detection at 500 nm (excitation at 400 nm). A calibration graph based on the rate of formation of product was rectilinear for up to 0.1 mg L-1 of creatine. The within-batch coefficient of variation at 40 µg L-1 was 2.3% (n = 10). The method can be applied to biological fluids.
Creatine Fluorescence Automation Computer Stopped-flow

"Drug Assays--the Role Of Modern Voltammetric Techniques"
J. Clin. Pharm. Ther. 1987 Volume 12, Issue 2 Pages 117-134
W. F. Smyth, A. D. Woolfson

Abstract: Modern voltammetric techniques, e.g. differential pulse polarography and voltammetry, anodic/cathodic stripping voltammetry and electrochemical detection for high performance liquid chromatography or flow injection analysis, are reviewed with respect to their basic theory, design and usage of available instrumentation and applications to drug assays in formulation and body fluid matrices.
Drugs Clinical analysis Polarography Voltammetry Voltammetry Voltammetry Review Theory

"Picomolar Quantitation Of Potassium Using A Continuous-flow Apparatus"
Kidney Int. 1989 Volume 36, Issue 4 Pages 726-729
Jeffrey L Garvin

Abstract: A new instrument capable of measuring mM concentration. of K in nl-samples such as those obtained from isolated, perfused tubule studies is described. The potassiometer is based on a commercially available K electrode and requires little custom machining. A continuously flowing stream carries the sample to the detector. Sample is injected into the stream and the resulting change in electrode voltage is displayed on a chart recorder.
Potassium Electrode Small sample

"Automated HPLC Analysis System For Direct Determination Of Catecholamines And Their Metabolites In Biological Matrices"
Labor Med. 1987 Volume 10, Issue 7-8 Pages 344-350
Boos, K.S.;Wilmers, B.;Sauerbrey, R.;Schlimme, E.

Abstract: This method for routine determination of adrenaline and noradrenaline in body fluids involves use of a laboratory-prepared SEC-HPAC (phenylboronic acid - vinyl polymer) column packing, a microprocessor-controlled column-switching technique and an integrated system for post-column derivatization and trihydroxyindole fluorescence monitoring. It permits direct injection of an appropriate biological fluid (500 µL) and has a detection limit of 2 pg.
Catecholamines Adrenaline Noradrenaline SEC Fluorescence Post-column derivatization

"Use Of An Enzyme Electrode With Immobilized Glucose Oxidase In A Continuous-flow System For Glucose Determination In Body Fluids"
Z. Med. Lab. Diagn. 1981 Volume 22, Issue 2 Pages 83-88
Bertermann, K.; Scheller, F.; Pfeiffer, D.; Jaenchen, M.; Lutter, J. (SFS)

Abstract: Glucose was determined in body fluids (e.g. blood) with an enzyme electrode in a continuous-flow system which included a sample reservoir, a pump, a thermostat, a glucose meter, a printer, and a temperature-regulated measurement cell. The H2O2, which was produced by immobilized glucose oxidase, was oxidized anodically at a potential of +600 mV, then O2 was determined The sensitivity was 3.2 mg/100 mL, and the standard curve was linear to 400 mg/100 mL. Relative standard deviations were 2.06 and 2.12% for 55 and 220 mg glucose/100 mL, respectively. There was a good correlation between values determined by the title application and by an automated method (r = 0.9805). Approximately 30-60 measurements/h could be made. (SFS)
Glucose Electrode Immobilized enzyme Method comparison

"Versatility Of The Titanium(IV)–Porphyrin Reagent For Determining Hydrogen Peroxide"
Bull. Chem. Soc. Jpn. 2003 Volume 76, Issue 10 Pages 1873-1888
Kiyoko Takamura and Chiyo Matsubara

Abstract: Hydrogen peroxide has been an important analyte in many fields for many years. The Ti-TPyP reagent, i.e., an acidic aqueous solution of oxo[5,10,15,20-tetra(4-pyridyl)porphyrinato]titanium(IV) complex, was developed as a highly sensitive spectrophotometric reagent for determining traces of hydrogen peroxide. Following the addition of hydrogen peroxide to the reagent, the absorbance at 432 nm decreased and a new peak appeared at 450 nm (the Soret band) accompanied by the consumption of the complex and the formation of its monoperoxo complex, respectively. The degrees of the absorbance changes were found to be proportional to the hydrogen peroxide concentration with the apparent molar absorptivities of 1.9 x 105 (432 nm) and 1.1 x 105 (450 nm) M-;1 cm-;1 (1 M = 1 mol dm-;3). Both values are much larger than those obtained by the conventional analysis methods. Based on these facts, the determination of hydrogen peroxide was made by a batch method and a flow injection analysis (FIA) method with the detection limits of 25 pmol and 0.5 pmol per test, respectively. In this account, the Ti-TPyP reagent is assessed for determining hydrogen peroxide in rainwater and in the atmosphere, and for determining several components in foods and biofluids mediated by appropriate oxidase enzymes, to demonstrate its potential for a broad range of applications.
Hydrogen peroxide Spectrophotometry Optimization Method comparison