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
Website: @unf

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Classification: Oil -> gasoline

Citations 12

"Determination Of Lead In Gasoline By A Flow Injection Technique With Atomic Absorption Spectrometric Detection"
Anal. Chim. Acta 1986 Volume 179, Issue 1 Pages 491-496
Colin G. Taylor and John M. Trevaskis

Abstract: The organic lead compound is oxidized with iodine (3% in toluene) and the product is diluted with a solution of 1% of Aliquat 336 (methyltrioctylammonium chloride) in isobutyl methyl ketone. This solution is injected into a carrier stream of acetone for aspiration into the air - acetylene flame for measurement at 283.3 nm. The response is rectilinear for up to 16 mg L-1 with a limit of detection of 0.1 mg l-1. The standard deviation is between 2 and 5 mg L-1 for gasoline containing between 328 and 384 mg L-1 (n = 4). The results agree closely with those obtained by AAS and titrimetry.
tetraalkyllead Spectrophotometry Method comparison

"Solvent Extraction In Continuous-flow Systems With Intelligent Zone Sampling"
Anal. Chim. Acta 1989 Volume 226, Issue 2 Pages 255-269
Purnendu K. Dasgupta and Wei Lei

Abstract: A portion of extractant (50 to 100 µL) is injected into a flowing reagent stream that passes through an extraction coil of residence time 1 to 3 min, and the extractant is isolated as it flows through the loop of an injection valve, which is activated by sensing by conductivity probes or by appropriate timing. The extractant can then be injected into a second stream for further chemistry before detection of the analyte. The effects of parameters, such as the coil material, configuration and diameter, or the phase ratio and flow rate, were studied. Examples include extraction of C1 to C5 alkanethiols from gasoline, extraction of a dye from aqueous fluoricarbon surfactant solution, and extraction of alkylbenzenesulfonates from water into CHCl3 as its methylene blue ion-pair. In the latter instance, the calibration graph was rectilinear up to 5 µg mL-1 of dodecylbenzenesulfonate; the coefficient of variation for 2.5 µg mL-1 was 1.3%. The detection limit was 50 ng mL-1, and a sampling rate of 60 h-1 should be attainable.
Thiols Spectrophotometry Sample preparation Zone sampling Ion pair extraction Optimization Solvent extraction

"Direct Determination Of Benzene In Gasoline By Flow Injection Fourier Transform Infrared Spectrometry"
Anal. Chim. Acta 1993 Volume 274, Issue 2 Pages 267-274
Máximo Gallignani, Salvador Garrigues and Miguel de la Guardia

Abstract: Gasoline samples (300 µL), diluted 1:9 in hexane, were directly injected into hexane carrier (flow rate 0.28 mL min-1). Peak-height FTIR absorbance measurements were performed at 675 cm-1 and the baseline was established between 712 and 650 cm-1. The calibration graph was rectilinear from 0.02% (detection limit) to 0.8% benzene and the coefficient of variation (n = 5; 0.4% level) was ~1%. The results agreed with those obtained by offline and online standard additions methods. A rapid quality control method was developed which involved the online injection of gasoline samples (diluted 1:9 in hexane) into a carrier stream of 0.5% benzene in hexane; in this case the baseline corresponded to the max. benzene level in gasoline allowed by EC legislation. Samples with a benzene content higher than this upper limit gave positive peaks. The procedure was used to analyze a series of commercial gasoline samples and the results compared well with those of GC.
Benzene Spectrophotometry Method comparison Standard additions calibration

"Flow Injection Derivative Fourier Transform Infrared Determination Of Methyl T-butyl Ether In Gasolines"
Anal. Chim. Acta 1993 Volume 282, Issue 3 Pages 543-550
Miguel de la Guardia, Máximo Gallignani and Salvador Garrigues

Abstract: Unleaded gasoline (10 ml) was diluted with n-hexane to 25 mL and a 320 µL portion of the solution was injected into a stream of n-hexane (0.45 ml/min). FTIR detection between 1350-800 cm-1, using a 0.117 mm path length flow cell with KBr windows, was performed and the first-order derivatives were calculated between 1209-1201 cm-1. Samples spiked with the cited compound (I) from 0.4-1.2% gave recoveries in the range 98.2-101.2%, with a RSD of 0.6% for samples containing 0.8% of I. The calibration graph was linear from 0.035% (limit of detection) to 1.5% of I in n-hexane and results (discussed) compared favourably with those obtained by GC.
Methyl-t-butylether Spectrophotometry Method comparison

"Vapor Generation Fourier Transform Infrared Spectrometric Determination Of Benzene, Toluene And Methyl Tert.-butyl Ether In Gasolines"
Anal. Chim. Acta 1996 Volume 333, Issue 1-2 Pages 157-165
Emilio López-Anreus, Salvador Garrigues and Miguel de la Guardia*

Abstract: A simple and fast procedure has been developed for the direct and simultaneous determination by Fourier transform infrared (FTIR) spectrometry of benzene, toluene and methyl tert.-butyl ether (MTBE) in gasoline samples. The method is based on the injection of 1 µl of gasoline into an electrically heated Pyrex glass reactor in which the sample is volatilized at 90°C. The vapor generated is transported by means of a nitrogen carrier flow of 400 mL min-1 inside an IR multiple pass gas cell and the spectrum in the mid-IR region is registered between 1600 and 500 cm-1 as a function of time. The flow injection recordings obtained for the LR bands between 671-675 cm-1, 727-731 cm-1, and 1210-1214 cm-1 were employed for the determination of benzene, toluene and MTBE respectively, using different criteria for establishing the baseline correction. Results obtained in the analysis of commercial samples of gasoline agree with those found by gas chromatography and another FTIR reference procedure.
Benzene Toluene Methyl-t-butylether Spectrophotometry Gas phase detection Volatile generation Method comparison Volatile generation

"Comparative Study Of Different Approaches For The Flow Injection Fourier Transform Infrared Determination Of Toluene In Gasolines"
Talanta 1994 Volume 41, Issue 5 Pages 739-745
M. Gallignani, S. Garrigues, M. de la Guardia, J. L. Burguera and M. Burguera

Abstract: Three different approaches were evaluated for the determination of toluene in gasolines. The first used a simple flow injection procedure, based on the use of absorbance values. The sample was diluted 1:9 with hexane, into a hexane carrier stream (0.28 ml/min) and the corresponding FTIR spectra was obtained as a function of time. The second method was a flow injection FTIR derivative procedure. Flow injection recordings were established from the first and second order derivative spectra. The third method was based on the use of band quotient between the first order derivative values at the wave number characteristics of toluene and benzene. With the first method and measurement of absorbance at 728 cm-1 the detection limit was 0.01%. With the second method the detection limit was 0.01%.
Toluene Spectrophotometry

"Determination Of Water By Flow Injection Analysis Using Karl Fischer Reagent With Electrochemical Detection"
Analyst 1985 Volume 110, Issue 7 Pages 847-849
Richard E. A. Escott and Arthur F. Taylor

Abstract: The flow injection determination of water in organic samples by use of amperometric and potentiometric detection systems with different electrode combinations and cell configurations was studied; the best results were obtained in a potentiometric system with a platinum indicator electrode and a calomel or silver reference electrode. In the procedure described, samples (50 µL) were injected via an autosampler into a stream (0.56 mL min-1) containing a 20% solution of Karl Fischer reagent in methanol - xylene (1:1), which was then passed through an 80-cm mixing coil. The detector comprised a 1.5-mm diameter horizontal tube with the indicator electrode sealed into the base upstream of a ceramic plug, which was also sealed into the base and connected by silicone-rubber tubing to the reference electrode, which was elevated above the tube. Calibration graphs based on peak height were rectilinear for 0 to 1500 ppm of water and the max. sampling rate was 60 h-1. The method was also applied to the analysis of gasoline - alcohol blends.
Water Amperometry Electrode Karl Fischer analysis Potentiometry

"Flow Injection Fourier Transform Infrared Spectrometric Determination Of Oil And Greases: Preliminary Microwave-assisted Extraction Studies"
Analyst 1996 Volume 121, Issue 8 Pages 1031-1036
Yasmina Daghbouche, Salvador Garrigues and Miguel de la Guardia

Abstract: Mineral oil, edible oil, gasoline or petroleum samples were dissolved in CCl4. A portion (300 ml) of the resulting solution was injected into a carrier stream of CCl4 at a flow rate of 1.5 ml/min. The area under the FTIR absorbance spectrum from 3058-2780 cm-1, corrected for a baseline established between 3200 and 2700 cm-1, was used for quantification. The detection limit was 0.6-1.1 mg/ml oils and greases; RSD was 1.4-4.1% (n=10). The throughput was 60 samples/h. The method was also applied to aqueous solutions containing different types of oils, after microwave-assisted extraction of the oil into CCl4 by irradiation at 420 W for 6 min. Results are presented and discussed.
Sample preparation Spectrophotometry Organic phase detection Solvent extraction Microwave

"Sorbent Isolation And Elution With An Immiscible Eluent In Flow Injection Anlysis"
Anal. Chem. 1989 Volume 61, Issue 5 Pages 496-499
Wei Lei, Purnendu K. Dasgupta, Jorge L. Lopez, and Don C. Olson

Abstract: The use of a flow injection carrier that is immiscible with the sample matrix is illustrated. To determine thiols in gasoline, the sample is passed through a column of Amberlite IRA-401-S strongly basic anion exchanger (OH- form) on which the thiols are concentrated. A portion of aqueous NaOH (>1M) is then injected into the gasoline stream before the column, and elutes the thiols and regenerates the column. This solution enters a flow of the same NaOH, which is mixed with a stream of 1 M NaHCO3 as buffering agent; 1 mM 5,5'-dithiobis-(2-nitrobenzoic acid) is then introduced and the absorbance is measured at 450 nm. To determine aniline in benzene, the mixture is passed through a column of Rexyn-101 strongly acid cation-exchange resin (H+ form), which retains aniline. A portion of 0.1 M H2SO4 is then introduced to elute aniline from the column, and after this flow has merged with more 0.1 M H2SO4 the absorbance is measured at 280 nm. The sensing and delay circuits are illustrated. Response was rectilinear up to 2 mM for thiols and up to 10 ng mL-1 for aniline. Further possible applications are discussed.
Aniline Thiols Spectrophotometry Preconcentration Buffer Amberlite Rexyn

"Low-pressure Inductively Coupled Plasma Ion Source For Molecular And Atomic Mass Spectrometry"
Anal. Chem. 1994 Volume 66, Issue 20 Pages 3400-3407
E. Hywel Evans, Warren Pretorius, Les Ebdon, and Steve Rowland

Abstract: Cyclic voltammetry (CV), UV/visible absorption spectroscopy, and electrospray mass spectrometry (ES-MS) are used in conjunction to study the mono- and/or dications produced in solution from the reaction of three model compounds (b-carotene, cobalt(II) octaethylporphyrin (CoIIOEP), nickel(II) octaethylporphyrin (NiIIOEP)), in three different solvent/electron-transfer reagent systems (methylene chloride/0.1 trifluoroacetic acid (TFA) (v/v), methylene chloride/0.1 TFA/2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) (v/v/200 mM), methylene chloride/0.1 TFA/0.1 antimony pentafluoride (SbF5) (v/v/v)). The reactions were carried out online with ES-MS by means of flow injection. Correlation of the CV data for these analytes with the ionic species determined to be in the solution on the basis of UV/visible absorption spectra and/or on the basis of the ionic species observed in the gas phase by ES-MS, along with our previously published data on these solvent/reagent systems, allowed an effective oxidation potential range, E, to be assigned to these solvent/reagent systems: methylene chloride/0.1 TFA (v/v), 0.6 V ETFA < 0.7 V; methylene chloride/0.1 TFA/DDQ (v/v/200 mM), 0.8 V ETFA/DDQ < 1.0 V; methylene chloride/0.1 TFA/0.1 SbF5 (v/v/v), 1.3 ETFA/SbF5 < 1.5. Knowledge of the solvent/reagent oxidation potentials and the electrochemical redox potentials of a particular analyte of interest allows a solvent/reagent system to be chosen to selectively ionize an analyte, or a range of analytes, to a desired ionic state for subsequent analysis by ES-MS. The ability to detect, in the gas phase, an ionic species produced in solution by chemical electron transfer will depend, however, on the stability of the ion in the given solvent/reagent system and on whether the ion can survive intact the transfer to the gas phase via the ES process. Copyright 1994, American Chemical Society.
Ionic strength Lead Voltammetry Spectrophotometry Mass spectrometry

"Inline Flow Injection Extraction-preconcentration Through A Passive Hydrophilic Membrane. Determination Of Total Phenols In Oil By Flow Injection Analysis"
Fresenius J. Anal. Chem. 1997 Volume 357, Issue 8 Pages 1066-1071
J. F. van Staden and H. E. Britz

Abstract: Phenols were extracted and pre-concentrated from a xylene donor solution, or oil sample, using a selective passive hydrophilic Spectrapor membrane (up to 6000-8000 Da mol. wt.). The extracted phenols were diffused to a basic acceptor stream and the pre-concentrated phenolate was injected into a carrier stream of 4-aminoantipyrine (4-AAP). The carrier stream was then merged with an oxidant stream of K2S2O8. Analysis was carried out using a Unicam 8625 spectrophotometer with a 80 µL flow-through cell; detection was at 500 nm. Optimal flow rates were 1 and 2.5 ml/min for the xylene and the buffered 4-AAP streams, respectively. The system was suitable for the determination of total phenols in oil. Calibration graphs were linear from 1-600 mg/l phenol; detection limits were 0.09, 0.18 and 0.02 mg/l phenol, o-cresol and m-cresol, respectively. RSD was n = 14). Sampling rate was 12 samples/h. The results compared favourably with those obtained using a standard manual 4-AAP and a standard GC method.
Phenols Phenol 4-Cresol 2-Cresol Spectrophotometry Sample preparation Preconcentration Hydrophilic membrane Method comparison Optimization Extraction

"Measurement Of Mercaptans In Gasoline"
Microchim. Acta 1989 Volume 99, Issue 1-2 Pages 35-41
Wei Lei, Purnendu K. Dasgupta, Steve D. Matza and Don C. Olson

Abstract: Portions (10 µL) of 4 mM 5,5'-dithiobis-(2-nitrobenzoic acid) and 2% ethylenediamine solution, each in methanol - acetone (4:1), are injected into a flowing stream of gasoline. The product, viz, 2-nitro-5-mercaptobenzoate, is detected at 412 nm after ~15 s. Calibration graphs were rectilinear for all of the C1 to C10 thiols examined. The system is intended for determination of 64 ppm of S.
Thiols Mercaptans Spectrophotometry Organic phase detection