Papers by Antony Calokerinos
Analytica Chimica Acta, 2004
In the Czech Republic no study on the levels of brominated flame retardants in human milk has bee... more In the Czech Republic no study on the levels of brominated flame retardants in human milk has been conducted, yet. In the first step analytical method for determination of PBDEs in this bioindicator matrix was implemented. Liquid-liquid extraction (LLE) (hexane, diethyl ether), followed by gel permeation chromatography was employed for isolation of PBDEs. Identification and quantification of PBDEs was carried out by GC-MS operated in negative chemical ionisation (NCI). Two mass spectrometric technologies, one employing quadrupole and the other one high resolution (HR) time-of-flight (TOF) analyzer, etc. were used in our study. Detection limits (LODs) obtained by quadrupole analyzer ranged from 0.02 to 0.05 ng g −1 lipid weight, using high resolution time-of-flight analyzer LODs were significantly lower, ranging from 0.002-0.005 ng g −1 lipid weight, what enabled detection of minor PBDE congeners. Within this pilot study 103 breast milk samples, obtained from mothers living in Olomouc region, were examined. Ten PBDE congeners were determined. All samples examined till now contained PBDEs residues, the dominating contaminant representing this group was congener BDE 47. In most of analysed samples levels of this compound ranged from 0.2 to 2 ng g −1 of lipid weight. Three exceptionally contaminated samples, containing levels of PBDEs 5-10 times higher than other samples, were found.
Analytica Chimica Acta, 1995
CONTRIBUTORS ix PREFACE xi ACKNOWLEDGEMENTS xiii CHAPTER 1 THE HISTORY OF MOLECULAR EMISSION CAVI... more CONTRIBUTORS ix PREFACE xi ACKNOWLEDGEMENTS xiii CHAPTER 1 THE HISTORY OF MOLECULAR EMISSION CAVITY ANALYSIS 1 A. Townshend CHAPTER 2 INTRODUCTION AND BASIC PRINCIPLES 5 A. C. Calokerinos 2.1 Flame Chemiluminescence 5 2.2 Historical Origins 6 2.3 Hydrogen Diffusion Flame 8 2.4 Salet Phenomenon 10 2.5 Molecular Emission Spectroscopy 12 2.6 Flame Photometrie Detector 13 2.7 Molecular Emission Cavity Analysis 13 2.7.1 Basic Principles 14 2.7.2 The Importance of the Salet Phenomenon in MECA 25 2.7.3 Sample Introduction into the Cavity 28 2.7.4 Molecular Emissions and Spectra 35 2.8 Conclusions 38 References 39 CHAPTER 3 INSTRUMENTATION AND AUTOMATION 43 N. Grekas References 96
Determination of polychlorinated biphenyls by liquid chromatography following cloud-point extraction
Analytica Chimica Acta, 1998
In this study, a new methodology, based on the `cloud-point phenomenon' of non-ionic surfact... more In this study, a new methodology, based on the `cloud-point phenomenon' of non-ionic surfactants, is applied for the extraction and preconcentration of polychlorinated biphenyls (PCBs). Once the PCBs are extracted from the solution, they are determined by liquid chromatography. The non-ionic surfactants used are polyoxyethylene 4-lauryl ether (Brij 30) and polyoxyethylene-10-oleyl ether (Brij 97). In this study, the optimum conditions for the preconcentration and determination of PCBs have been established and the method has been applied to determine PCBs in sea-water samples.
Analytical Letters, 2015
Since the first event in Izmir, 1998, many analytical chemists from all over the world have also ... more Since the first event in Izmir, 1998, many analytical chemists from all over the world have also attended these biennial conferences. The statistical distribution of those who have participated in the previous six events showed that the AACD conferences have become an international event widely accepted as a forum for presenting new trends and developments in analytical chemistry; discussing new applications of environmental, food, and industrial analysis with a special emphasis to quality aspects; promoting the presentation of young scientists' research; and exchanging ideas and promoting collaborations for joint research projects. The Ninth Aegean Analytical Chemistry Days (AACD2014) was organized in Chios, which is a Greek island in the North Aegean Sea. All scientific sessions were held in Homerion Cultural Center of Chios Municipality which is in the city center within walking distance from all hotels (Figures 1 and 2).
Determination of ammoniacal nitrogen in fertilisers by molecular emission cavity analysis
Analyst, 1977
... MECA 0.88 2.12 4.6 4.5 4.8 5.5 6.3 8.1 9.4 13.1 1 ... Received January 17th, 1977 Depavtment ... more ... MECA 0.88 2.12 4.6 4.5 4.8 5.5 6.3 8.1 9.4 13.1 1 ... Received January 17th, 1977 Depavtment of Chemistry, University of Birmingham, PO Box 363, Birmingham, B15 2TT R. Belcher SL Bogdanski A. C. Calokerinos Alan Townshend Downloaded by google on 01 January 2011 ...
Chemiluminescence in Flow Injection Analysis
Biomedical Chromatography, Mar 1, 1997
Continuous-flow chemiluminometric determination of amiloride and streptomycin by oxidation with N-bromosuccinimide
Analytica Chimica Acta, May 1, 1994
Abstract A rapid continuous-flow method for the determination of 0.50–15.0 μg ml −1 of amiloride ... more Abstract A rapid continuous-flow method for the determination of 0.50–15.0 μg ml −1 of amiloride and 2.00–30.0 μg ml −1 of streptomycin is described. The method is based on the chemiluminogenic oxidation of the analytes by N -bromosuccinimide in alkaline solution. The procedure is automated and solutions can be analysed at a rate of 250 h −1 with a relative error of about 1.6%. When applied to commercial formulations, the procedure was relatively free from interferences from common excipients. The method is evaluated by a recovery study and by the analysis of commercial formulations. The results obtained for the assay of commercial pharmaceutical preparations compared well with those obtained by the official methods and demonstrated good accuracy and precision.
Analytica Chimica Acta, Aug 1, 1994
A flow injection chemiluminescent (FI-CL) method was developed for the determination of pioglitaz... more A flow injection chemiluminescent (FI-CL) method was developed for the determination of pioglitazone HCl. It is based on the sensitizing effect of the drug on the oxidation reaction of sulfite with cerium(IV). The different experimental parameters affecting the chemiluminescence intensity, such as concentration of reagents and some physical parameters of the manifold, were carefully studied and incorporated into the procedure. The method permits the determination of 0.05-3.0 mg ml-1 of pioglitazone HCl with correlation coefficient r = 0.9999. The lower limit of detection (LOD) is 0.01 mg ml-1 (S/N = 2) and the lower limit of quantitation (LOQ) is 0.05 mg ml-1. The proposed method was compared with other reported methods and was found to be equally accurate and precise. It was successfully applied to the determination of the drug in pharmaceutical preparations and in biological fluids.
Talanta, Nov 1, 1990
Snnnnnry-The chemiluminescence produced by oxidation of thiamine by ferricyanide in alkaline medi... more Snnnnnry-The chemiluminescence produced by oxidation of thiamine by ferricyanide in alkaline medium has been investigated by using a simple continuous flow analyser and a procedure developed for the determination of thiamine hydrochloride or nitrate in the range 2.00 x 10-5-5.00 x lo-'M (equivalent to 6.75-169 pg/ml thiamine hydrochloride) with coefficients of variation ~2%. A measurement rate of 112jhr can be obtained. When applied to pharmaceutical formulations, the only interferent among common excipients and coexisting drugs is ascorbic acid. The results obtained for the assay of dosage forms compared well with those obtained by an official method and demonstrated an error ~4%.
Analytical and Bioanalytical Chemistry, May 28, 2010
Analytica Chimica Acta, 1983
The effect of various experimental parameters on the slope and the deviations from linearity of t... more The effect of various experimental parameters on the slope and the deviations from linearity of the S, calibration graph for thiourea when the S, excited species are generated on a m.e.c.a. cavity are studied. Previous explanations for the negative deviations at high concentrations are investigated and the formation of a stable sulphur allotrope is proposed to explain this effect.
Biomedical Chromatography, Mar 1, 1997
The optimized conditions and validation results are shown in Table 1, and further studies on the ... more The optimized conditions and validation results are shown in Table 1, and further studies on the emission enhancement of this system by different fluorescent reagents have been conducted, the results of which are presented in Fig. 1. The proposed system will be applied to the analysis of tiopronin in a commercial pharmaceutical formulation and possible interference effects from classical adjuvants were also evaluated. In addition, extrapolation of the technique to detection in an HPLC setup has simultaneously been carried out and the results, which will be introduced in a subsequent paper, are promising. Figure 2. Precision of determination of tiopronin at 50 M, RSD less than 2% (n = 10). Y. ZHAO ET AL.
Determination of ammonium- and nitrate-nitrogen by molecular emission cavity analysis
Analyst, 1981
... S. L. Bogdanski,; AC Calokerinos$ and Alan Townshendy Department of Chemistry, University of ... more ... S. L. Bogdanski,; AC Calokerinos$ and Alan Townshendy Department of Chemistry, University of Birmingham, PO Box 363, Birmingham, B15 2TT ... The ammonia generated is swept by nitrogen into a molecular emission cavity analysis (MECA) oxy-cavity and the intensity of the ...
Direct potentiometric titration of thiosulfate, thiourea, and ascorbic acid with lodate using an iodide ion-selective electrode
Microchemical Journal, Dec 1, 1983
Abstract A potentiometric method has been developed for the semi-automatic direct titration of th... more Abstract A potentiometric method has been developed for the semi-automatic direct titration of thiourea, thiosulfate, and ascorbic acid with potassium iodate in strongly acidic solutions using an iodide ion-selective electrode to monitor the reaction and locate the endpoint. The method is simple, fast, precise, and accurate. Amounts ranging from 0.15–1.5 mg of thiourea (3.9 × 10 −4 –3.9 × 10 −3 , M ), 0.3–3.0 mg of thiosulfate (5.4 × 10 −4 –5.4 × 10 −3 , M ), and 0.5–5.0 mg of ascorbic acid (5.7 × 10 −4 –5.7 × 10 −3 , M ) have been determined with an average error of about 1%. The method has been applied to the determination of ascorbic acid in tablets. Results checked closely with those obtained with a standard titrimetric method.
Flow-injection chemiluminometric determination of steroids
Analytica Chimica Acta, May 1, 1994
Abstract A rapid, accurate, precise and fully automated flow-injection method is described for th... more Abstract A rapid, accurate, precise and fully automated flow-injection method is described for the determination of 0.02–0.50 μg ml −1 cortisone, 0.02–1.00 μg ml −1 hydrocortisone and 0.20–5.00 μg ml −1 dexamethasone in aqueous solutions and of 1.0–20.0 μg ml −1 prednisolone, methylprednisolone, progesterone, corticosterone and testosterone and 2.0–20.0 μg ml −1 betamethasone in 20% (v/v) acetonitrile solutions. The methods is based on the sensitizing effect of each steroid on the chemiluminogenic cerium(IV)sulphite reaction. Limits of detection are in the ranges 0.013–0.019 and 0.05–4.00 μg ml −1 for aqueous and acetonitrile solutions, respectively. Common excipients do not interfere greatly and the mean recovery of steroids from commercial formulations was 102.6% (range 94.2–109.0%). The method allows the measurement of up to 100 samples per hour and can be used for content uniformity tests and the results were in good agreement with the official method for commercial formulations with a relative error
Analytica Chimica Acta, 2000
A flow injection chemiluminescent (FI-CL) method was developed for the determination of pioglitaz... more A flow injection chemiluminescent (FI-CL) method was developed for the determination of pioglitazone HCl. It is based on the sensitizing effect of the drug on the oxidation reaction of sulfite with cerium(IV). The different experimental parameters affecting the chemiluminescence intensity, such as concentration of reagents and some physical parameters of the manifold, were carefully studied and incorporated into the procedure. The method permits the determination of 0.05-3.0 mg ml-1 of pioglitazone HCl with correlation coefficient r = 0.9999. The lower limit of detection (LOD) is 0.01 mg ml-1 (S/N = 2) and the lower limit of quantitation (LOQ) is 0.05 mg ml-1. The proposed method was compared with other reported methods and was found to be equally accurate and precise. It was successfully applied to the determination of the drug in pharmaceutical preparations and in biological fluids.
Analytica Chimica Acta, 2000
A fast and simple flow injection chemiluminometric method for the determination of trace amounts ... more A fast and simple flow injection chemiluminometric method for the determination of trace amounts of tetracycline (TC) and its major degradation products epitetracycline (ETC), epianhydrotetracycline (EATC) and anhydrotetracycline (ATC) based upon the action of potassium hexacyanoferrate(III) in alkaline solution has been developed. The analytes can be determined with 10σ limits of quantification of 0.5 g for ETC, 2.0 g for TC, 0.01 g for EATC and 0.04 g for ATC. The sensitivity for TC is greatly improved by acidic degradation prior to the chemiluminescence (CL) measurement. The method developed allows measurement within the ranges of 0.040-2.0 g TC and ATC, 0.50-5.0 g ETC and 0.01-2.0 g EATC.
Continuous-flow molecular emission cavity analysis for organic sulphur compounds by alkaline hydrolysis
Analytica Chimica Acta, 1988
Abstract Alkaline hydrolysis of various organic sulphur compounds (thioacetamide, thiosemicarbazi... more Abstract Alkaline hydrolysis of various organic sulphur compounds (thioacetamide, thiosemicarbazide, thiodiacetic acid and dithiooxamide) in a continuous-flow analyzer produces sulphide which can be removed from the solution after acidification. Hydrogen sulphide evolved is measured by molecular emission cavity analysis. Samples can be analyzed at a rate of 30 h −1 with a relative error of 1–2%.
CONTRIBUTORS ix PREFACE xi ACKNOWLEDGEMENTS xiii CHAPTER 1 THE HISTORY OF MOLECULAR EMISSION CAVI... more CONTRIBUTORS ix PREFACE xi ACKNOWLEDGEMENTS xiii CHAPTER 1 THE HISTORY OF MOLECULAR EMISSION CAVITY ANALYSIS 1 A. Townshend CHAPTER 2 INTRODUCTION AND BASIC PRINCIPLES 5 A. C. Calokerinos 2.1 Flame Chemiluminescence 5 2.2 Historical Origins 6 2.3 Hydrogen Diffusion Flame 8 2.4 Salet Phenomenon 10 2.5 Molecular Emission Spectroscopy 12 2.6 Flame Photometrie Detector 13 2.7 Molecular Emission Cavity Analysis 13 2.7.1 Basic Principles 14 2.7.2 The Importance of the Salet Phenomenon in MECA 25 2.7.3 Sample Introduction into the Cavity 28 2.7.4 Molecular Emissions and Spectra 35 2.8 Conclusions 38 References 39 CHAPTER 3 INSTRUMENTATION AND AUTOMATION 43 N. Grekas References 96
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Papers by Antony Calokerinos