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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Surface

Classification: Environmental -> water -> surface

Citations 46

"Application Of Chromaticity Characteristics For Direct Determination Of Trace Aluminum With Eriochrome Cyanine R By Diffuse Reflection Spectroscopy"
Anal. Chim. Acta 2000 Volume 408, Issue 1-2 Pages 145-151
Natalija I. Ershova and Vadim M. Ivanov

Abstract: Eriochrome cyanine R (ECR) has been applied as immobilized reagent for the direct determination of aluminum by diffuse reflection spectroscopy. Sorption ability of aluminum species depends on the kind of solid support and increases in the following sequence: anionite AV-17 < silica gel < chromaton-N- super < cellulose. Chromaticity characteristics of the aluminum sorbates, namely, color Lightness (L), chromaticity coordinates (A, B), saturation (S), hue (T), brightness (Y), whiteness (W), yellowness (G), and the total color difference (Delta E), indicate better sensitivity and precision than the diffuse reflection coefficient. The experimental parameters (optical characteristics, acidity of aqueous solution, shaking time, volume of aqueous solution, etc.) affecting the sorption of aluminum species have been optimized. The detection limit is 0.004 mg/l for the aluminum complex immobilized on cellulose. The precision and accuracy of the proposed method was evaluated with real samples, e.g. surface water, salt CH3COONa.
Aluminum Spectroscopy Silica gel Optimization Cellulose Immobilized reagent

"Determination Of The U-234/U-238 Ratio In Water Samples By Inductively Coupled Plasma Mass Spectrometry"
Anal. Chim. Acta 2000 Volume 422, Issue 2 Pages 203-208
L. Halicz, I. Segal, I. Gavrieli, A. Lorber and Z. Karpas

Abstract: U-234 belongs to the U-238 natural radioactive decay series, and at equilibrium, the abundance ratio, U-234/U-238, corresponds to the ratio of their half-lives, i.e. 54.8 x 10^-6. In natural waters, deviations from this ratio reflect radioactive and geochemical processes and can be correlated with the flow path of the water. Alpha spectrometry or thermal ionization mass spectrometry require tedious procedures for separation and pre-concentration of the uranium prior to analysis. Inductively coupled plasma quadrupole mass spectrometry can yield reliable results for the U-234/U-238 ratio without any treatment of the sample (except acidification). Here, we show that combining a flow injection sample introduction system with an ultrasonic nebulizer, significantly increases the sensitivity and enhances the ability to cope with a relatively high salt content in non-saline water samples. The relative standard deviation attained is 5% at 50 pg L-1 U-234. The method is extremely fast (1 min per measurement); pre-treatment is not required and 1 mL of the sample is needed for triplicate measurements. Therefore, it may be used as a fast screening method.
Uranium-234 Uranium-238 Mass spectrometry Isotope ratio

"Determination Of Triazines In Surface Waters By Membrane Separation Coupled Online To A Flow Injection System And Partial Least Squares Regression"
Anal. Chim. Acta 1996 Volume 321, Issue 2-3 Pages 147-155
R. Carabias Mart&iacute;nez*, E. Rodr&iacute;guez Gonzalo, M. P. Santiago Toribio and J. Hern&aacute;ndez M&eacute;ndez

Abstract: An FIA method was developed for screening natural water for chloro- and methyl-thiotriazines. The FIA manifold was equipped with a membrane separation module fitted with a microporous polypropylene membrane (0.025 mm thickness, 0.04 µm pore size) which allowed the analytes to be extracted from a continuously circulating sample stream and to be pre-concentrated into a stationary acceptor solvent (100 µL hexane). At the end of the 3 min pre-concentration period, the acceptor solution was propelled to the detection cell (18 µL volume) of the diode-array spectrophotometer where the spectrum for 220-250 nm was recorded. The overlapping signals of chloro- and methyl-thiotriazines were resolved by a partial least squares method. The RSD (n = 10) for the analysis of binary mixtures containing 80-400 µg/l of terbutryne and propazine were 6%. The detection limits for terbutryne and propazine were 4.8 and 4.5 µg/l, respectively.
Herbicides, triazine Thiotriazines, chloro Thiotriazines, methyl Spectrophotometry Membrane Partial least squares Preconcentration

"Flow Injection Determination Of Anionic Surfactants With Cationic Dyes In Water Bodies Of Central India"
Analyst 1998 Volume 123, Issue 8 Pages 1691-1695
Rajmani Patel and Khageshwar Singh Patel

Abstract: A new, simple and specific flow injection analysis (FIA) procedure for the determination of anionic surfactants, viz., sodium lauryl sulfate (SLS), sodium dodecyl sulfonate, sodium hexadecyl sulfonate and sodium dodecyl benzenesulfonate, with cationic dyes, viz., Brilliant Green, Malachite Green, Methylene Blue, Ethyl violet and Crystal Violet, in water bodies, viz., ponds, tube wells, rivers and municipal wastes, of central India (east Madhya Pradesh) is described. It is based on the precipitation of the cationic dyes with the anionic surfactant due to formation of an ion-associated species within the pH range 5.5-8.0. The apparent molar absorptivity of the ion-associated species formed with various anionic surfactants and cationic dyes is in the range (0.60-1.50) x 104 L mol-1 cm-1 at λmax 590-665 nm. Among them, the pair BG+-LS- was selected for detailed investigation. The detection limit (amt. causing absorbance >3s) of the method with BG is 100 ppb SLS and the sample throughput is 50 h-1. Optimization of FIA and the anal. variables in the precipitation and determination of SLS with BG is described. The method is free from interferences from almost all ions which are commonly present with the surfactant. The proposed method was applied to the mapping of SLS pollution levels in the various water bodies. All surface waters and municipal waste waters and some ground waters lying near the sources were found to be contaminated with SLS beyond permissible limits.
Surfactants, anionic Sodium lauryl sulfate Sodium dodecyl sulfonate Sodium hexadecyl sulfonate Sodium dodecylbenzenesulfonate Spectrophotometry Ion pair formation pH Optimization Interferences

"A Fast Determination Of Nitrate In Rain And Surface Waters By Means Of UV Spectrophotometry"
Fresenius J. Anal. Chem. 1976 Volume 280, Issue 5 Pages 365-368
J. Slanina, W. A. Lingerak and L. Bergman

Abstract: Organic substances are the main interference in the direct U.V. spectrophotometric determination of nitrate at 210 nm. An active carbon filter (Filopur) is therefore proposed which adsorbs all organic interferences. With this filter the U.V. spectrophotometric method gives the same results as the Na-salicylate method. The reproducibility is generally better than 5 %. One determination takes 50 s.
Nitrate Spectrophotometry Activated carbon

"Fast Determination Of Nitrate In Small Samples Of Rain And Surface Waters By Means Of UV Spectrophotometry And Flow Injection Analysis"
Fresenius J. Anal. Chem. 1978 Volume 289, Issue 1 Pages 38-40
J. Slanina, F. Bakker, A. G. M. Bruijn-Hes and J. J. M&ouml;ls

Abstract: An UV-spectrophotometric determination of NO3- in small samples (0.5 mL) of rain and surface waters is described. A variant of flow injection analysis is used in combination with an active C filter for removal of organic interferences. The accuracy and the reproducibility of the method are >3%. One determination takes 30 s.
Nitrate Spectrophotometry Activated carbon Interferences Small sample

"Simultaneous Determination Of Sodium, Potassium, Magnesium And Calcium In Surface, Ground And Domestic Water By Flow Injection Analysis"
Fresenius J. Anal. Chem. 1980 Volume 302, Issue 5 Pages 370-374
Willem D. Basson and Jacobus F. Van Staden

Abstract: A simple, rapid, automated method is described for simultaneous determination of Na, K, Mg, and Ca in surface, ground, and domestic water, which is based on using the flow injection technique in combination with flame photometry and atomic absorption spectrophotometry. The method makes possible the anal. of ~128 samples/h with a coefficient of variation for Na <2.1%, for K <1.7%, for Ca <2.7%, and for Mg <1.8% (during 16 tests for each sample).
Sodium Potassium Magnesium Calcium Spectrophotometry Spectrophotometry Simultaneous analysis Automation

"Automated Turbidimetric Determination Of Sulfate In Surface, Ground And Domestic Water By Flow Injection Analysis"
Fresenius J. Anal. Chem. 1982 Volume 310, Issue 3-4 Pages 239-242
Jacobus F. van Staden

Abstract: A simple, modified, automated method for the turbidimetric determination of sulphate in surface, ground and domestic water, based on the principles of the flow-injection technique, is described. The one loop of a two-position sampling valve is used to sample an alkaline buffer-EDTA solution, alternated with water samples on the other loop. This ensures that the residual precipitate, coating the walls of the flowcell, is redissolved and the system kept clean. The method is suitable for the analysis of sulphate at a rate of up to 60 samples per hour with a coefficient of variation of better than 0.95 %.
Sulfate Turbidimetry

"Automated Prevalve Sample Filtration In Flow Injection Analysis. Determination Of Sulfate In Water Removing Suspended Solids And Color Before Sampling"
Fresenius J. Anal. Chem. 1982 Volume 312, Issue 5 Pages 438-440
Jacobus F. van Staden

Abstract: Suspended solids and the presence of organic substances and color are the main interferences in the turbidimetric spectrophotometric determination of sulphate at 420 nm in water. An automated flow-injection procedure is proposed in which these interferences are automatically removed by using an active carbon filter, which is incorporated in the flow system between the sampler and the sampling valve system. With this automated prevalve sample filter the proposed turbidimetric method gives the same results as a standard flow injection and an automated segmented method where the above mentioned interferences are manually removed prior to sampling. The method is applicable for the analysis of sulphate in surface, ground and domestic waters in the concentration range up to 200 mg/l at a sampling rate of up to 60 samples per hour with a coefficient of variation of better than 1%.
Sulfate Turbidimetry Filter Sample valve manipulation

"Automated Prevalve Dilution In Flow Injection Analysis. The Automated Determination Of Chloride In Surface, Ground And Domestic Water"
Fresenius J. Anal. Chem. 1985 Volume 322, Issue 1 Pages 36-41
Jacobus F. van Staden

Abstract: Surface, ground or domestic water was subjected to flow injection analysis. The sample was mixed with Fe(SCN)2+ and the absorbance was measured at 480 nm. The calibration graph was rectilinear for 120 mg L-1 of Cl- and the coefficient of variation were 1.16%.
Chloride Spectrophotometry

"Investigations On The Equivalence Of Analytical Procedures - Flow Injection Analysis And DIN Method In The Determination Of Orthophosphate In Surface Water"
Fresenius J. Anal. Chem. 1988 Volume 329, Issue 6 Pages 711-713
G. Schulze Contact Information und A. Thiele

Abstract: Sample solution is injected into a carrier stream (H2O, 2.0 mL min-1), mixed with 1% (NH4)6Mo7O24.4H2O solution in 0.6 M H2SO4 (0.8 mL min-1) and further mixed with 0.2% hydrazinium sulfate in 0.5 M H2SO4 (0.6 mL min-1). Detection of molybdenum blue is at 690 nm. Calibration of the procedure is discussed. Results obtained for six water samples by this method and by the DIN method show total similarity for only one sample; for the others the results are equivocal.
Phosphate Spectrophotometry Method comparison Standard method Tecator

"Potential Of Modified Reverse Flow Injection Analysis For Continuous Monitoring And Process Control"
Fresenius J. Anal. Chem. 1988 Volume 329, Issue 6 Pages 668-674
Wolfgang Frenzel

Abstract: The transient detector response observed after injection of standard solution into a continuously flowing sample stream is a measure of the concentration. of standard added to the continuous sample concentration. Calibration of the monitoring system is discussed and compared with that of other systems. Full details are given for application of the technique in the photometric determination of Cl- in tap water, PO43- in surface water and the potentiometric determination of F-, and each analysis is discussed.
Chloride Phosphate Fluoride Potentiometry Spectrophotometry Calibration Process control Reverse Theory

"Online Sample Preparation And Determination Of Phenols With A Flow Analysis Method"
Fresenius J. Anal. Chem. 1992 Volume 342, Issue 4-5 Pages 426-428
C. Kwade Contact Information, R. Voigtl&auml;nder and K. Cammann

Abstract: A flow-analysis system has been developed to automate the phenol determination according to the German standard method DIN 38409-H16-2. The automation leads to a significant acceleration of the procedure. One analysis only lasts 3 min while the complete manual determination requires 3 h. Also the sample, solvent and reagent volumes are reduced to a tenth of the volumes demanded by the standard method. The described phenol determination is based on the integration of an air segmented ('Airsegmented-Flow-Analysis' SFA) part in a flow injection analysis (FIA) system. The main steps of the analytical procedure are: Reproducible inserting of the sample in a carrier stream, sample pretreatment and sample measuring. In the first step the sample is injected into the carrier stream. It transports the sample in the reaction coil and than through the distillation unit. The steam distillation represents the sample preparation step; therefore an air segmented stream is necessary. Afterwards the different phases (liquid and gas) were singled again and the distilled solution is fed into the FIA manifold. The determination itself takes place inside the FIA system. The limit of determination amounts to 0.01 mg L-1 with a standard deviation of 1.5%. Different waste, surface and drinking water samples have been analyzed without any problems. The results correspond very well to those obtained by manual procedure.
Phenols Spectrophotometry Standard method Segmented flow Method comparison

"Speciation Of Antimony By Atomic Absorption Spectrometry. Applicability To Selective Determination Of Antimony(III) And Antimony(V) In Liquid Samples And Of Bioavailable Antimony In Sediments And Soil Samples"
Microchim. Acta 1992 Volume 109, Issue 1-4 Pages 149-155
Mar&iacute;a Beatriz de la Calle Gunti&ntilde;as, Yolanda Madrid and Carmen C&aacute;mara

Abstract: Speciation of Sb(III) and Sb(V) by AAS in liquid samples was evaluated by investigating the (i) determination of Sb(III) and SbV in water by selective extraction with lactic acid - malachite green by graphite-furnace AAS; (ii) determination of Sb(III) and Sb(V) by hydride-generation - AAS coupled to flow injection, batch and continuous-flow systems; (iii) mineralization methods for soil samples. Different sample pre-treatments were evaluated in terms of recovery of total Sb and the ability to speciate Sb(III) and SbV by slurry formation in soil and sediments. The graphite-furnace extraction method was the most convenient method for speciation of Sb(V) and Sb(III) in surface and seawater.
Antimony(3+) Antimony(5+) Spectrophotometry Spectrophotometry Speciation Slurry

"Determination Of Organolead Compounds And Of Chromate Beside Chromium(III)"
Microchim. Acta 1992 Volume 109, Issue 1-4 Pages 137-140
Bernd Neidhart and Christoph Tausch

Abstract: The pre-concentration. and determination of ionic alkyl-lead compounds in surface water and human urine and tetra-alkyl-lead compounds in ambient air are described. Preconcentration and cleanup steps were followed by HPLC separation. Ionic species were pre-concentrated by solid-phase extraction; detection was performed online. The alkyl-lead species were eluted from the HPLC column, partially de-alkylated by iodine solution to form dialkyl-lead species and detected as PAR [4-(2-pyridylazo)resorcinol] complexes after the reduction of excess iodine with thiosulfate and adjustment to pH 9 to 10. Difficulties in the validation of trimethyl-lead and dimethyl-lead in some matrices are discussed. A Cr(VI) speciation method consisting of selective biosampling using human erythrocytes and gas-furnace AAS and reversed flow injection analysis is described.
tetraalkyllead Chromium(VI) Spectrophotometry Reverse Speciation

"Sensitive Liquid Chromatographic Determination Of Alkyl-, Nitro- And Chlorophenols By Pre-column Derivatization With Dansyl Chloride, Post-column Photolysis And Peroxyoxalate Chemiluminescence Detection"
J. Chromatogr. A 1991 Volume 553, Issue 1 Pages 345-356
P. J. M. Kwakman, D. A. Kamminga and U. A. Th. Brinkman, G. J. De Jong

Abstract: Aqueous phenol-containing solution was adjusted to pH 12 with 1 M NaOH, treated with aqueous tetrabutylammonium bromide and dansyl chloride in CH2Cl2. After mixing, a portion of the organic phase was applied to an amino-bonded SPE column and the dansyl derivatives were eluted with CH2Cl2. The eluate was evaporated to dryness and the residue was dissolved in aqueous 50% methanol. A portion of the solution was analyzed by LC on a column (20 cm x 3.2 mm) of LiChrosorb RP-18 (3 µm) with methanol - imidazole buffer of pH 7 as eluent (gradient elution details given). After chromatography, the dansyl derivatives were irradiated in a photochemical reactor (cf. Scholten et al., ibid, 1980, 199, 239) before 2-nitrophenyl oxalate - H2O2 in acetonitrile were added to the column eluate (for chemical excitation); peroxyoxalate chemiluminescence detection at 470 nm (excitation at 340 nm) was used. The method was applied to determine several phenolic compounds in surface water; detection limits were 0.01 to 0.1 ng mL-1.
Phenols, alkyl Phenols, chloro Phenols, nitro Chemiluminescence LC Buffer Column pH Pre-column derivatization Reactor Sensitivity Post-column derivatization

"Polar, Hydrophilic Compounds In Drinking Water Produced From Surface Water. Determination By Liquid Chromatography - Mass Spectrometry"
J. Chromatogr. A 1991 Volume 554, Issue 1-2 Pages 251-266
H. Fr. Schr&ouml;der

Abstract: Samples from waste water treatment-plants, surface waters and drinking water treatment plants were solid-phase extracted (details given) and the cited compounds were detected and identified by LC - tandem MS coupled online by a thermospray interface (details given). After identification, quantification by direct mixture analysis by the system without derivatization and separation, was possible with the availability of standards and with use of flow-injection analysis (details given). Use of GC - MS (described) was only useful for detection of volatile compounds.
Organics, polar LC Mass spectrometry Sample preparation Extraction Interface

"Fast Screening Method For Eight Phenoxyacid Herbicides And Bentazone In Water. Optimization Procedures For Flow Injection Analysis-thermospray Tandem Mass Spectrometry"
J. Chromatogr. A 1993 Volume 647, Issue 2 Pages 329-339
Ren&eacute; B. Geerdink and Paul G. M. Kienhuis, Udo A. Th. Brinkman

Abstract: A two-step procedure was used to optimize instrumental parameters in the cited techniques (details given). Surface or drinking water (3-5 mL) was injected into a carrier solution (1.5 ml/min) of 0.1 M ammonium acetate/acetonitrile (9:1) and analyzed by MS with a thermospray interface at vaporizer and source block temperature 105 and 200°C, respectively. The parent ion intensities were obtained in the single-scan Q3-MS scan mode and daughter ions after collision with Ar at 3-4 mTorr and collision offset voltage l8 and 22 eV, respectively, for phenoxyacid herbicides and bentazone (I). Multiple-reaction monitoring was used with monitoring of two parent ion-daughter ion pairs for the phenoxyacids and one parent and three daughter ions for I (m/e values given). Calibration graphs were linear for 50 µg/l of each analyte with detection limits of 0.2 µg/l for 2,4,5-(trichlorophenoxy)propionic acid to 0.8 µg/l for 2,4,5-(trichlorophenoxy)acetic acid. The method was fully automated with a sample analysis time of 10 min. Results obtained agreed well with those of LC with UV detection.
Herbicides Bentazone 2,4,5-Trichlorophenoxypropionic acid 2,4,5-Trichlorophenoxyacetic acid Mass spectrometry Optimization Method comparison

"Enhanced Ion Chromatography With Sequential Flow Injection Analysis. Determination Of Common Anions And Nitrite"
Am. Environ. Lab. 1998 Volume 10, Issue 2 Pages 6-7
Karmarkar, S.V.

Abstract: Nitrite and F-, Cl-, NO3- Br-, HPO42-, SO42- were determined in wastewater, , groundwater and surface water samples by enhanced ion chromatography with sequential flow injection anal.
Fluoride Chloride Nitrate Bromide Sulfate Nitrite HPIC Sequential injection

"Method Of Flow Injection Analysis - Chloride Estimation In Water"
Cesk. Hyg. 1989 Volume 34, Issue 3 Pages 174-178
Krajak, V.

Abstract: An outline of the principles behind the flow injection analysis (FIA) method is given, and benefits of this method in rapid and easy anal. of a large number of samples are discussed. The method was applied with good results to the determination of Cl- in potable and surface waters using Hg(SCN)2 as the reagent and a spectrophotometer as the detector. (SFS)
Chloride Spectrophotometry

"Gas Diffusion Flow Injection Analysis Applied To The Determination Of Sulfite And Sulfur Dioxide In Environmental Samples"
Chem. Anal. 1995 Volume 40, Issue 4 Pages 619-630
Frenzel, W.;Hillmann, B.

Abstract: To determine free sulfite, sample (300 µL) was injected into a carrier stream (1.2 ml/min) of water which merged with a stream (0.8 ml/min) of 0.2 M H2SO4 and passed through a reaction coil (60 cm x 0.7 mm i.d.). The SO2 produced was transferred to a stream (0.6 ml/min) of color reagent (50 mg 4,4'-dithiodipyridine, 10 mL ethanol and 1.02 g potassium hydrogen phthalate diluted to 250 mL with H2O) in a gas diffusion unit. It then passed through a reactor (45 cm x 0.7 mm i.d.) and the absorbance was measured at 324 nm. To determine gaseous SO2 collected in formaldehyde solution, samples (500 µL) were injected into a H2 carrier and treated with 0.45 M NaOH prior to acidification and release of SO2 (FIA manifold shown). The calibration graphs were linear for 0.25-10 and 0.5-20 mg/l free and bound sulfite, respectively, and the detection limits were 0.08 and 0.15 mg/l, respectively. The RSD were 1-3% and the sampling frequency was 20-30/h. Interferences were investigated. The methods were applied to the determination of sulfite in tap, surface and waste waters and brine, and to the determinations of SO2 in air (details given).
Sulfite Sulfur dioxide Spectrophotometry Gas diffusion Interferences

"Miniaturization Of Solid-phase Reactors For Online Post-column Derivatization In Narrow-bore Liquid Chromatography"
Chromatographia 1985 Volume 20, Issue 8 Pages 453-460
H. Jansen, U. A. Th. Brinkman and R. W. Frei

Abstract: Two systems based on the cited concept are described; both give good results, their principal advantage being economy. One system comprises a stainless-steel tube (4 cm x 1 mm) packed with Aminex A-28 (9 µm; acetate form) for determination of N-methylcarbamate pesticides and the other a similar tube packed with urease immobilized on silica for determination of urea. The eluate from either reactor is mixed with phthalaldehyde (for fluorimetric detection) by use of a low-dead-volume T-piece. An online pre-column trace-enrichment procedure is described for determination of N-methylcarbamates in surface waters; limits of determination are at the low-ppb level.
Carbamates, N-methyl LC Fluorescence Post-column derivatization Preconcentration Miniaturization

"Simultaneous Determination Of Iron And Copper In Waters By Multiligand Flow Injection Analysis"
Collect. Czech. Chem. Commun. 1988 Volume 53, Issue 7 Pages 1461-1475
Kuban, V.;Gladilovich, D.B.

Abstract: The spectrophotometric characteristics were studied and optimum conditions were established for the determination of Fe and Cu with mixtures of disodium 2,9-dimethyl-4,7-diphenyl-1,10-phenanthrolinedisulfonate(I) with disodium 4,7-diphenyl-1,10-phenanthrolinedisulfonate(II) or 3-(2-pyridyl)-5,6-bis(4-sulfophenyl)-1,2,4-triazine (disodium salt) in static and dynamic flow injection systems. In the recommended procedure, 30 µL water samples containing Fe and Cu in concentration. ratios from 1:10 to 10:1 are injected into a stream of 0.6 M I - 0.2 mM II in 0.1 M formate buffer (pH 3.5) - 0.01 M ascorbic acid. The coefficient of variation for 4 to 40 µM-Fe and -Cu were 2 and 5%, respectively. In the reverse flow injection method, 25 µL of reagent mixture is injected into the acid sample stream; multi-channel diode-array detection is used. The coefficient of variation for Fe and Cu concentration. of 1 to 43 µM in ratios of 10:1 to 1:15 is ~2%. The methods were applied in the analysis of drinking and surface waters.
Iron Copper Spectrophotometry Multicomponent Reverse Optimization Simultaneous analysis

"Mass Spectrometric Detection And Identification Of Polar Pesticides And Their Degradation Products: A Comparison Of Different Ionization Methods"
Environ. Monit. Assess. 1997 Volume 44, Issue 1-3 Pages 503-513
H. FR. Schr&ouml;der

Abstract: Due to increasing use of polar pesticides, they are found together with their degradation products in ground- and surface waters serving for drinking water treatment. The triazine derivatives acetamido-atrazine, ametryne, atrazine, cyanazine, deethylatrazine, deethyldeisopropyl-hydroxyatrazine, deethyl-hydroxyatrazine, deisopropyl-atrazin, deisopropyl-hydroxyatrazine, desmetryn, hydroxyatrazine, prometryne, propazine, simazine, terbumeton, terbutryne and terbutylazine, and the pesticides 2,4-D, dichlorprop, isoproturon, diuron, metolachlor, glyphosate, metsulfuronmethyl and dalapon, all of them belonging to this type of pesticides, have been studied. For determination of triazine derivatives UV detection by means of diode array detector (DAD) as well as mass spectrometric (MS) detection coupled by thermospray interface (TSP) have been used successfully after liquid chromatoraphic (LC) separation. Interfaces like thermospray (TSP), electrospray (ESP) and atmospheric pressure chemical ionization (APCI) were examined with regard to their suitability for substance-specific detection of polar pesticides by flow injection analysis (FIA) with MS- and tandem mass spectroscopic detection (MS/MS) without preceding LC separation. Optimized detection conditions for these pesticides using FIA are presented, and solutions for occurring problems are offered.
Pesticides Mass spectrometry Mass spectrometry Mass spectrometry Optimization

"Determination Of Trace Amounts Of Nickel By Online Flow Injection Analysis Ion-exchange Preconcentration Atomic Absorption Spectrometry"
Fenxi Huaxue 1984 Volume 12, Issue 11 Pages 997-999
Fang, Z.L.;Xu, S.K.;Zhang, S.

Abstract: The flow injection technique combined with ion-exchange pre-concentration permitted efficient online determination of Ni by AAS Miniature columns (3.5 cm x 2.5 to 3.0 mm) of PVC or glass were used, packed with chelating resin (type 122; 60 to 100 mesh) with a salicylic acid functional group, and sealed at both ends with nylon net (100 mesh). By means of a multi-functional rotating sampling valve, it was possible to carry out sampling, ion exchange, elution with 2 M HCl and AAS determination sequentially. A 20-fold improvement in sensitivity for the determination of 10 to 500 µg L-1 of Ni was attained; the coefficient of variation at the 500 µg L-1 level was 1.5%. Recovery from tap water and surface water was 90 to 106%. The effect of factors which affect sensitivity, viz, particle size of the exchange resin, column dimension and flow rate of eluate, are considered. Interference from various metals has been investigated.
Nickel Ion exchange Spectrophotometry Interferences Chelation Resin Preconcentration

"Determination Of Phenols In Surface Water With Flow Injection Analysis"
Fenxi Huaxue 1986 Volume 14, Issue 5 Pages 359-362
Yan, H.;Li, F.;Li, Y.

Abstract: The flow injection analysis was carried out with 0.05 M Na2CO3 - NaHCO3 buffer and aqueous 1% NaCl as carrier solution at a flow rate of 4.4 mL min-1 and an applied electrode potential of +0.6 V. The electrode response was rectilinear for concentration. of phenols of ppb to ppm with a coefficient of variation of 2% and a detection limit of 2 ppb.
Phenols Electrode

"Determination Of Fluoride In Water By Flow Injection Potentiometry With The Ion-selective Electrode"
Fenxi Huaxue 1987 Volume 15, Issue 9 Pages 825-827
Cui, H.;Fang, Z.L.

Abstract: A filtered sample of well- or surface water was mixed with a total-ionic-strength-adjustment buffer composed of NaCl, Na acetate, Na citrate and 36% acetic acid. The F- content of this mixture, calibrated against standard solution of F-, was determined by flow injection potentiometry with an ion-selective electrode that incorporated an AlF3 single-crystal slice. Optimum conditions were established with use of 200 ppb of F- in the carrier liquid to increase the stability and speed of response, reduce the signal noise of the potentiometer, and avoid interference by OH-. The detection limit was 0.02 ppm, the standard deviation (n = 11) for 0.5 ppm of F- was ±0.1 mV, and a sampling rate of 80 h-1 was achieved.
Fluoride Electrode Potentiometry Interferences

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

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

"Application Of Flow Injection Analysis With An Amperometric Detector. 2. Analysis Of Trace Free Cyanide In Surface Water By Flow Injection Analysis"
Huanjing Huaxue 1983 Volume 2, Issue 4 Pages 58-65
Ma, Huichang; Jin, Li; Yan, Huiyu

Abstract: Trace cyanide in surface water was determined by amperometry using a gold-tube electrode detector and the flow injection analysis technique with NaOH solution as the carrier fluid. A Pb-granule (20-50 mesh) column (0.35 x 5 cm) treatment can eliminate S2- interference. The cyanide detection limit and relative standard deviation is 1 ppb and <3%, respectively. The measurement frequency using the method is 60-70 times/h.
Cyanide, free Amperometry Column Solid phase extraction

"Application Of Amperometric Flow-through Gold Tubular Detector Determination Of Trace Sulfide Ion By Flow Injection Analysis"
Huanjing Huaxue 1984 Volume 3, Issue 5 Pages 75-79
Ma, Huichang; Yan, Huiyu

Abstract: The amperometric detector using a Au-tubular electrode is suitable for trace sulfide determination in surface water and pulp wastewater at pH > 5-6 and applied external voltage +300 mV. The linear response covers three orders of magnitude in the ppb ppm range, the relative standard deviation is ≤3%, and the detection frequency is 60/h. Interference by phenol and cyanide is insignificant at pH 5-6.
Sulfide Amperometry Electrode Interferences

"Determination Of Potassium, Sodium, Calcium And Magnesium In Surface Water By Flow Injection Analysis"
Huanjing Wuran Yu Fangzhi 1989 Volume 11, Issue 4 Pages 43-45
Zhou, Zhifa; Xu, Wenbin; Ye, Shuaiguan

Abstract: A flow injection analysis - atomic absorption spectrometry method for determining potassium ion, sodium in, calcium ion, and magnesium ion in surface water gave results in good agreement with those by the conventional atomic absorption spectrometry, and relative deviations of 5, 3, 4, and 3%, respectively.
Potassium Sodium Calcium Magnesium Spectrophotometry Method comparison

"Determination Of Zinc, Cadmium, Lead And Copper In Precipitation By Computerized Differential Pulse Voltammetry"
Int. J. Environ. Anal. Chem. 1985 Volume 19, Issue 2 Pages 85-98
Lingerak, W.A.;Van Wensveen Louter, A.M.;Slanina, J.

Abstract: A computerized flow injection analysis - differential pulse anodic-stripping voltammetric system is described and illustrated. Rain-water samples are made 0.2 M in HNO3 and filtered through Ederol 69K activated-carbon-impregnated filters, which retain organic matter; the metals are carried by buffered electrolyte solution to the flow-through cell, with a mercury-drop electrode, for deposition and anodic stripping. The system is controlled by an Apple II computer (details given). From 12.4 to 56.6 ppb of Zn, 0.18 to 0.76 ppb of Cd, 4.9 to 32.7 ppb of Pb and 0.8 to 7.9 ppb of Cu were determined by means of a calibration graph without the need for standard additions, and results were in agreement with those obtained by AAS. Application of the method to seawater, surface water and acid digests of biological samples is discussed.
Zinc Cadmium Lead Copper Electrode Sample preparation Voltammetry Computer Method comparison

"Identification Of Carbamates By Particle Beam/mass Spectrometry"
J. Mass Spectrom. 1997 Volume 32, Issue 1 Pages 43-54
Jaroslav Slobodn&iacute;k, Maria E. Jager, Sacha J. F. Hoekstra-Oussoren, Maarten Honing, Ben L. M. van Baar*, Udo A. Th. Brinkman

Abstract: The possibility of analyzing 33 carbamate pesticides and 14 of their transformation products was investigated utilizing flow injection particle beam/mass spectrometry (PBMS) with electron impact (EI) ionization and ammonia and methane positive and negative chemical ionization (CI). Optimum operating conditions of the interface and mass spectrometer in each mode were determined, with special attention given to spectrum quality; variables investigated included ion source temperature and ion source pressure in CI experiments. Ammonia, as a reagent gas, provided less fragmentation and better quantitative results than methane. The CI response was generally higher with positive ion detection (PCI) than with negative ion detection (NCI), but NCI was found to be highly selective for compounds such as aminocarb, asulam and thiophanate-methyl. As regards analyte detectability, EI performed best for most compounds, with the spectra providing relevant structure information. The response of more polar degradation products is generally larger by 2-3 orders of magnitude compared with the parent compounds. When analyzing real samples, the combined use of CI for molecular mass determination and EI for structure elucidation is required. The spectral information from this study and additional chromatographic data were used for the determination of low- and sub µg L-1 levels of the test carbamates in surface water.
Carbamates Mass spectrometry

"Flow Injection Analysis Of Trace Free Cyanide In Surface Groundwaters With An Amperometric Flow-through Detector"
Kexue Tongbao 1983 Volume 28, Issue 8 Pages 1145-1145
MA HUICHANG JIN LI YAN HUIYU

Abstract: The determination of ions of cyanide is one of the important subjects of environment monitoring. In conventional analytical methods, the procedure of distillation is usually required to eliminate the interference of sulfide. By using a gold tube flow-through electrode described in a previous report and inserting a lead-grain column into a flow injection analysis system, we have successfully determined the cyanide ions at ppb level. Because of the insertion of the lead column, the pretreatment of samples can be easily performed on line and the interference of 100 times sulfide is successfully prevented.
Cyanide, free Amperometry Electrode

"Automated Determination Of Total Alkalinity In Surface, Ground And Domestic Waters By Single-point Titration And Flow Injection Analysis"
Lab. Pract. 1980 Volume 29, Issue 6 Pages 632-637
Basson, W.D.;Van Staden, J.F.

Abstract: NA
Alkalinity Electrochemical analysis Electrode Electrode Buffer Titrations

"Enzyme-modified Carbon Paste Electrodes - A New Way To Reagent-free Enzymic Analysis"
Nova Acta Leopold., Suppl. 1998 Volume 15, Issue 1 Pages 155-175
Spohn, U.

Abstract: A review with many references. Enzyme modified carbon paste electrodes (CPEs) opens up a new way to the reagentless anal. of food and environmental samples as well as bioprocess media. Enzymes, cofactors, redox mediators and additives were immobilized at graphite particles suspended in an organic solvent. Short response times and low background currents were achieved. Peroxidase modified CPEs detect hydrogen peroxide in the range between 0.1 µM and 0.5 mM. Bienzyme modified CPEs were produced by coimmobilization of horseradish peroxidase or fungal peroxidase with oxidases, e.g. lactate oxidase and pyruvate oxidase to detect their substrates selectively at low potentials at -50 - +100 mV vs. Ag/AgCl in the micro- and millimolar range. The sensitivity and the operational stability of the bienzyme electrodes can be improved considerably by adding cationic polyelectrolytes, e.g. polyethylenimine, poly-L-lysine, poly-L-arginine alone or in combination with trehalose and lactitol. Tyrosinase modified CPEs detect phenols with free ortho-positions and dihydroxybenzene derivatives This CPEs were mounted into a flow through cell and combined with a membrane extraction enrichment step. Under FIA (flow injection anal.) conditions phenol and catechols can be determined in the ranges from 10 nM to 10 µM with and from 0.5 µM and 1 mM without enrichment. The membrane extraction step allows the direct anal. of surface and ground water. A D-lactate selective CPE was constructed by coimmobilization of D-lactate dehydrogenase. NAD+ and toluidine blue O bound on polymer backbone. D-lactate and NADH are detectable at -50 mV vs. Ag/AgCl. D-lactate was detected in the range between 20 µM and 20 mM.
Hydrogen peroxide Phenols Catechols d-Lactate Electrode Electrode Reagent consumption Review Membrane Extraction

"Development Of Enzyme-based Amperometric Sensors For The Determination Of Phenolic Compounds"
Trends Anal. Chem. 1995 Volume 14, Issue 7 Pages 319-328
Gy&ouml;rgy Marko-Varga*, Jenny Emn&eacute;us, Lo Gorton and Tautgirdas Ruzgas

Abstract: The development of biosensor-based techniques for the determination of phenolic compounds in surface waters is described. The enzyme's catalytic cycle must first be considered, and then the incorporation of enzyme electrodes into simple flow injection or integrated sample handling units. The catalytic properties of laccases, peroxidases and tyrosinases for the construction of sensors with narrow or broad selectivity can be exploited. (30 references).
Phenols Sensor Amperometry Review

"Evaluation And Comparison Of Ion Chromatography, Segmented-flow Analysis And Flow Injection Analysis For The Determination Of Nitrate In Natural Surface Waters"
Water Res. 1989 Volume 23, Issue 4 Pages 519-521
Eileen M. Burke, F. Xavier Suarez, Daniel C. Hillman,* and Edward M. Heithmar

Abstract: The cited techniques were used in the determination of nitrate (0.04 to 1.5 mg l-1) in water. Suppressed ion chromatography (IC) was performed on an AS4A column, with an AG4 pre-column and an anion micro-membrane suppressor, with a mobile phase (2 mL min-1) of 0.75 mM NaHCO3 - 2.2 mM Na2CO3. For segmented-flow analysis (SFA), a Technicon GTpc AutoAnalyzer II system was used with an ASTM Type II water carrier, sulfanilamide - N-(1-naphthyl)ethylendediamine dihydrochloride color reagent and NH4Cl - EDTA buffer system with a copperized-Cd reduction column. Flow injection analysis (FIA) was performed colorimetrically as in SFA with use of a dual-channel Lachat QuikChem system. The coefficient of variation, accuracy (% recovery) and detection limits were 3%, 103% and 7 µg L-1 for IC, 1%, 101% and 6 µg L-1 for SFA and 1%, 100% and 30 µg L-1 for FIA, respectively. Analysis times were 10 h-1 for IC (including simultaneous Cl- and SO42- determination), and 30 to 60 h-1 for SFA and FIA.
Nitrate HPLC Buffer EDTA Automation Detection limit Redox Injection technique Column Reduction column Segmented flow Lachat

"Flow Injection Analysis For Determining Total Alkalinity In Surface, Ground And Domestic Water Using The Automated Bromocresol Green Method"
Water SA 1984 Volume 10, Issue 3 Pages 168-174
van Staden JF; van Vliet HR

Abstract: The method (flow scheme given) is a combination of the flow injection and bromocresol green methods. Bromocresol green is used in CaCl2 - K H phthalate buffer medium (pH 4.0) and the absorbance is monitored at 610 nm. The reagent solution is stable for 5 days. The buffer capacity of the flow stream affects the rectilinearity of the results. Optimal results are obtained with sample sizes of 50 µL, and 120 samples can be analyzed hourly. The coefficient of variation is better than 1.40% (n = 14). Reproducibility is >99%.
Alkalinity Spectrophotometry

"Flow Injection Analysis Of The Total Alkalinity In Surface, Ground And Domestic Water Using A Single-point Titration System"
Water SA 1986 Volume 12, Issue 2 Pages 93-98
van Staden JF

Abstract: An electrometric single-point titration system for the determination of total alkalinity in surface, ground and domestic water is described. The method is based on a combination of flow injection analysis and single-point titration. The sample is reacted with an acid linear-response buffer solution and the pH of the resulting solution is measured with a glass electrode in a flowthrough assembly. The method is suitable for the analysis of total alkalinity at a rate of up to 120 samples per hour with a coefficient of variation of better than 0,8%. Color and turbidity interferences are eliminated.
Alkalinity, total Electrode Titrations Interferences

"Determination Of Phosphate At Low Concentrations In Surface Waters By Flow Injection Analysis"
Water SA 1988 Volume 14, Issue 3 Pages 125-130
Pauer JJ; van Vliet HR; van Staden JF

Abstract: A flow injection - molybdenum blue colorimetric method is described for the determination of PO43- by using SnCl2 stabilized with hydrazinium sulfate as reducing agent. The method is suitable for determination of 10 to 500 µg L-1 of PO43-. The precision is 0.5% at the 500 µg L-1 level. Silicon concentration. of 30 mg L-1 do not interfere, and interference from the preservative Hg(II) is negated by adding the same amount to both sample and standard solution .
Phosphate Spectrophotometry Interferences Optimization

"Automatic Determination Of Silica In Surface And Groundwater"
Water SA 1990 Volume 16, Issue 3 Pages 205-210
van Staden JF; Pauer JJ; van Vliet HR; Kempster PL

Abstract: An automated flow injection procedure for the determination of silica in surface and groundwater was developed. The reduced heteropoly molybdenum blue formed complex from molybdosilicic acid was used as detection product at 660 nm. Ascorbic acid was used as reductant and oxalic acid was used to decompose the molybdophosphoric acid complex eliminating the interference of phosphate. Interferences of a number of ions were assessed. The proposed method was evaluated in the range 0.07 to 20 mg/L Si. At a sample frequency of 90 samples per hour, good precision and accuracy were achieved and the carry-over between samples was less than 1%.
Silica Spectrophotometry Interferences

"A Capillary-based Amperometric Flow Immunoassay For 2,4,6-trichlorophenol"
Anal. Bioanal. Chem. 2003 Volume 375, Issue 1 Pages 125-132
Catalin Nistor and Jenny Emn&eacute;us

Abstract: This paper describes the development of two different capillary-based heterogeneous competitive flow immunoassay formats (capillary flow injection immunoassay (CFIIA) and capillary sequential injection immunoassay (CSIIA)) for the determination of 2,4,6-trichlorophenol (2,4,6-TCP). The assays are based on the competition between the analyte and an analyte derivative labelled with the enzyme β-galactosidase, for an anti-TCP antibody, followed by the injection of the mixture at equilibrium into a flow stream, where separation between the fractions bound and unbound to the antibody is performed in a glass capillary containing immobilized protein A. The antibody-tracer fraction retained inside the protein A capillary was measured by injection of 4-aminophenyl-β-D-galactoside (4-APG), followed by amperometric detection of the enzymatically generated 4-aminophenol (4-AP), leading to a negative correlation between the signal and the analyte concentration. The two immunoassay formats were compared in terms of sensitivity and speed, giving IC50 values of 1.41±0.03 and 1.64±0.07 µg L-1, detection limits of 0.2 and 0.4 µg L-1, and sample throughputs of 6 and 4 h-1 for the CFIIA and CSIIA system, respectively. The influence of different interfering chlorophenolic compounds in the assay was minor, with only one exception (i.e. 2,4-dichlorophenol). In addition, different water matrices were tested (surface, tap, and rain water), showing that the matrix influence was negligible, except for rainwater, which resulted in a 30% increase in sensitivity. As a conclusion, the assay is suitable for the fast screening of TCP present at low concentration levels in water samples.
2,4,6-Trichlorophenol Amperometry Immunoassay Interferences

"Miniaturized Capillary Electrophoresis System With Contactless Conductivity Detection And Flow Injection Sample Introduction"
Instrum. Sci. Technol. 2004 Volume 32, Issue 3 Pages 303-309
Lixin Wang and Chonggang Fu

Abstract: A miniaturized capillary electrophoresis (CE) system with contactless conductivity detection (CCD) and flow injection (FI) sample introduction was developed. It represents an ideal combination of high-resolution separation of CE with high throughput reproducible sample injection of FI, and universal and robust detection of CCD for the analysis of ionic species. Its design and fabrication method is described in detail. Performance tests of the system were performed for the analysis of surface water. It was found that complete separation of the cations studied (NH4+, K+, Ca2+, Na+, and Mg2+) could be obtained within 60 sec with peak height RSD better than 2.0%, thus achieving a sampling frequency of 60 hr-1. Detection limits were in the order of low µmolarity.
Ammonium Potassium Calcium Sodium Magnesium Electrophoresis Conductometry Injection technique