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: Waste -> sewage -> sludge

Citations 18

"Use Of Flow Injection Sample-to-standard Addition Methods For Quantification Of Metals Leached By Selective Chemical Extraction From Sewage Sludge"
Anal. Chim. Acta 1999 Volume 381, Issue 2-3 Pages 297-305
I. Lavilla, B. Perez-Cid and C. Bendicho

Abstract: The flow injection sample-to-standard addition method (FI-SAM) proposed by Israel and Barnes and a modification of it was employed for determination of the extractable contents of chromium, lead, nickel and zinc in a sewage sludge sample obtained from an urban wastewater processing plant. The new calibration method was a modification of the one established by Israel and Barnes in which the sample was injected into a blank solution and two different standard solutions. The advantages of this modified calibration method were: (i) sample consumption was minimized in comparison with the reverse flow injection method since the sample was not used as carrier; (ii) a blank that was matrix matched to the sample was not required; (iii) a similar precision was observed in comparison with the original procedure. For studying FI-SAM calibration strategies, extractable metals obtained by using two known sequential extraction schemes (Tessier and BCR) were determined. Only fractions that required calibration with the standard addition method for metal determination were considered. FI-SAMs compensate for interference effects caused by concomitants co-extracted at each stage of the sequential extraction scheme from sewage sludge, for all metals studied except for chromium.
Chromium Lead Nickel Zinc Spectrophotometry Standard additions calibration Extraction Reverse Interferences Method comparison

"Transient Oxidation Of Brucine In Solution As A Tool For The Determination Of Chromium(VI) And Brucine"
Anal. Chim. Acta 1983 Volume 146, Issue 1 Pages 181-190
Takeshi Yamane and Horacio A. Mottola

Abstract: The oxidation of the alkaloid brucine by chromium(VI) in sulfuric acid medium in the presence and absence of oxalic acid is described. Photometric monitoring of a red intermediate (λmax = 525 nm) permits determinations of both chromium (VI) and brucine at low concentrations (Cr(VI), 0-7.5 µg mL-1; brucine, 0-197 µg mL-1) in an unsegmented continuous-flow system by direct injection of the sample into the detection area. Detection limits are 0.1 µg mL-1 for chromium and 4 µg mL-1 for brucine. Other alkaloids structurally related to brucine (e.g., strychnine, yohimbine and corynanthine) do not give intermediates with the high molar absorptivity exhibited by brucine. Determination of chromium in water samples and standards is described.
Chromium(VI) Brucine Spectrophotometry

"Online Microwave Oven Digestion Flame Atomic Absorption Analysis Of Solid Samples"
Anal. Chim. Acta 1990 Volume 238, Issue 2 Pages 417-421
V. Carbonell, M. de la Guardia and A. Salvador, J. L. Burguera and M. Burguera

Abstract: A manifold has been developed for on-line microwave oven digestion and flame atomic absorption spectrometric (FAAS) determination of metallic elements in solid samples. The use of a closed flow system permits sample treatment before analysis by FAAS, the direct injection of slurries avoids a filtration step and the interconnection of two conventional rotary injection valves allows the rapid introduction of samples and standards. The determination of lead in sewage sludge was employed as a test system for the proposed on-line sample digestion manifold. The procedure has a limit of detection of 0.2 µg Pb g-1.
Lead Sample preparation Spectrophotometry Microwave Online digestion

"Rapid Determination Of Mercury In Environmental Materials Using Online Microwave Digestion And Atomic-fluorescence Spectrometry"
Anal. Chim. Acta 1995 Volume 308, Issue 1-3 Pages 364-370
A. Morales-Rubio, Ml. Mena and C. W. McLeod*

Abstract: A 70-300 mg portion of environmental material was dispersed in HNO3/H2O (3:2) to form a slurry. A 400 µL portion of the slurry was injected into a 0.01 M HCl carrier stream (2.5 ml/min) and passed through a digestion coil (4 m x 0.8 mm i.d.) mounted in a microwave oven (20 W). The flow passed through a cooling coil (2 m x 0.8 mm i.d.) at 0°C and a degassing module and was merged with a reductant stream (2.5 ml/min) containing 3% SnCl2 in 15% HCl. After passing through the reduction coil (10 cm x 0.8 mm i.d.), the flow entered the gas-liquid separator. The Hg vapor was swept to the atomic-fluorescence detector with an air stream (600 ml/min) and Hg was determined at 253.7 nm. The calibration graph was linear for 2-10 µg/l Hg, the detection limit was 0.23 µg/l and the RSD (n = 3) were ~e;0.5% within the linear range. The method was validated by analyzing certified reference materials including soil, sewage sludge and lake sediment.
Mercury Fluorescence Sample preparation Reference material Microwave Online digestion Phase separator Slurry

"Interference By Volatile Nitrogen Oxides In The Determination Of Mercury By Flow Injection Cold Vapor Atomic Absorption Spectrometry"
Talanta 1993 Volume 40, Issue 5 Pages 729-735
Inge Rokkjær, Boy Hoyer* and Nina Jensen,

Abstract: Volatile nitrogen oxides, formed as reduction products of HNO3 during sample decomposition, interfered with the flow injection AAS determination of Hg by scavenging the reducing agent, thus inhibiting Hg reduction. The interference effect was observed in the determination of Hg in sewage sludge digests and caused poor reproducibility of the mercury peak shape, the peak height being more affected than the peak area. Calibration by standard addition prevented systematic errors in the Hg determination and the interference could be remedied by purging the sample with Ar.
Mercury Spectrophotometry Interferences Standard additions calibration Peak shape

"Comparison Of Reflux And Microwave Oven Digestion For The Determination Of Arsenic And Selenium In Sludge Reference Material Using Flow Injection Hydride-generation And Atomic Absorption Spectrometry"
Analyst 1995 Volume 120, Issue 1 Pages 95-99
Rajananda Saraswati, Thomas W. Vetter and Robert L. Watters Jr.

Abstract: Sludge (0.25 g) was mixed with 5 mL concentrated HNO3 and 5 mL concentrated H2SO4, and a five-stage microwave oven digestion procedure (details tabulated) was used to digest the sample. The maximum temperature and pressure reached during the digestion were 175°C and 190 psi, respectively. The resulting solution was heated on a hot-plate until all the HNO3 was removed, and then diluted to 100 mL with 2% HCl. For As determination, 10 mL of the solution were treated with 5 mL of a solution of 10% KI and 5% ascorbic acid for 1 h before analysis. For Se determination, 10 mL of the solution was diluted to 100 mL with HCl (1:1), followed by heating at 90°C for 25 min before analysis. Analyses were performed by injecting the sample solution (40 µL) into a carrier stream of 10% HCl for subsequent reaction with a solution of 0.25% NaBH4 in 0.05% NaOH. The gaseous hydrides of As or Se produced were analyzed by AAS at 193.7 or 196 nm, respectively. Calibration graphs were linear from 5-20 and from 2-10 ng/ml of As and Se, respectively. The corresponding detection limits were 0.15 and 0.17 ng/ml. Microwave oven digestion with HNO3/H2SO4 provided results comparable to those obtained by reflux column digestion using HNO3/H2SO4/HClO4 and afforded shorter sample preparation times.
Arsenic Selenium Sample preparation Spectrophotometry Reference material Method comparison

"Atomic Absorption Spectrometric Analysis Of Solids With Online Microwave-assisted Digestion"
J. Anal. At. Spectrom. 1992 Volume 7, Issue 7 Pages 1085-1089
V. Carbonell, A. Morales-Rubio, A. Salvador, M. de la Guardia, J. L. Burguera and M. Burguera

Abstract: A description is given of a procedure for online microwave-assisted digestion of solid samples prior to analysis by flame AAS as described previously (Anal. Chim. Acta, 1990, 238, 417). A slurry of the sample is transported in HNO3 - H2O2 (1:1) to extract Cu and Mn quantitatively in a few min. Digestion times vary from 4 min for sewage sludges to 2 min for matrices like artichoke. Detection wavelengths were 324.7 nm for Cu and 279.5 nm for Mn. A closed flow injection system allows digestion to be conducted online. Sample flow rate was 2.8 mL min-1. Over 15 samples h-1 can be analyzed using the procedure which allows for sequential treatment of different samples. A procedure was developed for the online microwave-assisted digestion of solid samples and their anal. by flame atomic absorption spectrometry. The method involves the transport of a slurry of the sample in a 1+1 mixture of concentrated HNO3 and H2O2, which provides quant. extraction of Cu and Mn in a few minutes. Real samples of sewage sludges dispersed in 20 mL of HNO3 and H2O2 can be digested in 4 min and other matrixes, such as artichoke and diet samples dispersed in 10 mL of HNO3 and H2O2 are digested in only 2 min. A closed flow injection system permits the online digestion to be carried out; the use of two interconnected injection valves allows the measurement of standards during the digestion of samples. The method permits the anal. of more than 15 samples per h and provides accurate results, as demonstrated by the anal. of certified samples of sewage sludges and tomato leaves.
Copper Manganese Sample preparation Spectrophotometry Microwave Online digestion Slurry Reference material

"Analytical Characteristics Of An Inductively Coupled Plasma Mass Spectrometer Coupled With A Thermospray Nebulization System"
J. Anal. At. Spectrom. 1995 Volume 10, Issue 9 Pages 575-581
Hans Vanhoe, Steven Saverwijns, Magali Parent, Luc Moens and Richard Dams

Abstract: The effects of different matrix salts and mineral acids on analyte ion signals in ICP-MS was evaluated using the thermospray (TS) sample introduction system of Vanhoe et al. (Ibid., 1994, 99, 815). The results were compared with two other sample introduction systems, the pneumatic nebulizer coupled with a spray chamber (the conventional arrangement; CA) and the same nebulizer coupled with the desolvating unit employed with the thermospray nebulizer. Studies were effected with a 10 µg/l multi-element solution of Be, Al, Sc, Co, In, Gd, Tl, Th and U in 0.14 M HNO3 containing 1-5000 mg/l of the matrix elements Na, Ca, P and S (ICP-MS operating conditions tabulated). Non-spectroscopic interferences from Na and Ca were more pronounced for the TS system than the CA but were almost the same for P and S. The TS system was used for the analysis of Cd and Pb in three environmental reference materials (Community Bureau of Reference (BCR) Certified Reference Materials 141R Soil- calcareous loam, 144R sewage sludge-domestic and 146R sewage sludge-industrial, following digestion with aqua regia (experimental details given). A sample flow injection system was used to eliminate memory effects. Results obtained with the TS system agreed more closely with certified values than those obtained with the CA system.
Cadmium Lead Mass spectrometry Sample preparation Reference material Method comparison Interferences

"Interference Removal For Cadmium Determination In Waste Water And Sewage Sludge By Flow Injection Cold Vapor Generation Atomic Absorption Spectrometry"
J. Anal. At. Spectrom. 1998 Volume 13, Issue 10 Pages 1145-1149
María Liva Garrido, Riansares Muñoz-olivas and Carmen Cámara

Abstract: Cold vapor generation coupled to atomic absorption spectrometry using flow injection (FI-CVAAS) was evaluated as a rapid and simple method for the determination of Cd in wastewater and sewage sludge. Wastewater samples did not need any pre-treatment prior to anal. The sewage sludge was digested in a high pressure microwave oven to ensure good solubilization of the samples. Some elements in the sample (Cu, Pb, Ni, Zn) showed important interferences in the FI-CVAAS method. Elimination of such interferences by adding KCN to the borohydride solution is discussed. Validation of the method was achieved by analyzing a sewage sludge sample used in an interlab. exercise organized by the Water Research Center, UK, and by comparing the results with those obtained by electrothermal atomic absorption spectrometry (ETAAS) using a graphite furnace. Wastewater and sewage sludge samples were analyzed by both FI-CVAAS and ETAAS methods.
Cadmium Spectrophotometry Sample preparation Interferences Method comparison

"Immobilized Cyanobacteria For Online Trace Metal Enrichment By Flow Injection Atomic Absorption Spectrometry"
Anal. Chem. 1994 Volume 66, Issue 21 Pages 3632-3638
Angel Maquieira, Hayat A. M. Elmahadi, and Rosa Puchades

Abstract: Cyanobacteria (Spirulina platensis) immobilized on controlled pore glass pre-concentrate Cu(II), Zn(II), Cd(II), Pb(II), and Fe(III) from aqueous solution with high efficiency as ascertained using an online flow injection atomic absorption spectrometry system. The degree of metal binding depends on the pH of the solution. Quantitative retention of copper, zinc, and cadmium occurred at a wide range of pH values, while the retention for lead and iron was pH-dependent. The latter metals were adsorbed strongly only at pH 6 and 7, respectively. The breakthrough capacity was determined from the breakthrough curve, with values of 0.0035, 0.0008, 0.0011, 0.0028, and 0.0017 ng/mL for Cu, Zn, Cd, Pb, and Fe, respectively, being obtained. The analysis of a certified reference sample, sewage sludge of domestic origin (BCR No. 144), for cadmium and copper with a high accuracy ensures the feasibility of this technique for environmental analysis. Copyright 1994, American Chemical Society.
Copper Cadmium Lead Iron Spectrophotometry Immobilized cell Preconcentration pH Controlled pore glass Reference material

"Investigations On The Equivalence Of Analytical Procedures - Determination Of Chloride By Flow Injection Analysis And DIN Method In Water Analysis"
Fresenius J. Anal. Chem. 1989 Volume 334, Issue 1 Pages 9-12
G. Schulze, O. Elsholz, R. Hielscher, A. Rauth, S. Recknagel und A. Thiele

Abstract: Water was de-gassed and analyzed by one of the following methods. (i) A portion is injected into a stream of water, then mixed with a 15% methanolic solution of 2 mM Hg(SCN)2, 80 mM Fe(NO3)3 and 50 mM HNO3 and the absorbance is measured at 463 nm. (ii) A portion is injected into a stream of water, then mixed with 0.7 M Na acetate followed by 0.1 M Na acetate containing 1 mg mL-1 of Cl-. Detection is by means of tubular silver flow-through electrodes. (iii) A portion is injected into a stream of 2 M HNO3, this is mixed with a solution of 100 mg L-1 of AgNO3, the ppt. is filtered off and the filtrate is analyzed by AAS at 328.1 nm. The results obtained were reproducible and accurate and compared well with those obtained by the German standard (DIN) method. The methods developed were faster and more economic in the use of reagents than the standard method. For methods (i), (ii) and (iii), 120, 180 and 40 samples h-1, respectively, could be analyzed.
Chloride Spectrophotometry Spectrophotometry Electrode Precipitation Filter Standard method

"Automatic Flow Injection System For The Determination Of Heavy Metals In Sewage Sludge By Microwave Digestion And Detection By Inductively Coupled Plasma Atomic-emission Spectrometry."
Fresenius J. Anal. Chem. 1996 Volume 355, Issue 2 Pages 112-119
Luis Bordera, Vicente Hernandis and A. Canals

Abstract: An automated dual-channel flow injection manifold was used to determine heavy metal concentrations of 77.7-4059 µg/g in sewage sludge. A suspension of sewage sludge containing 0.5-0.75% of solids in 1.5 M HNO3 was loaded into a digestion coil (3 m x 0.8 mm i.d.) and subjected to microwave radiation at 662 W for 360 s. The digest (~e;6 ml) was inserted into a 1.5 M HNO3 carrier stream (1 ml/min) and propelled to the sequential ICP-AES spectrometer where signals for Zn (213.856 nm), Cu (324.756 nm), Pb (220.353 nm), Cr (283.563 nm), Cd (228.802 nm) and Ni (231.604 nm) were recorded. The method was validated by analyzing a certified reference material (BCR No. 146) and relative errors of -4.8 to +2% were obtained for all elements apart from Ni (-10.4%). The complete analysis took ~e;12 min.
Metals, heavy Zinc Copper Lead Chromium Cadmium Nickel Sample preparation Spectrophotometry Reference material Microwave Online digestion Slurry

"Some Observations On The Sensitivity Of Flow Injection Techniques For Atomic Absorption Spectrophotometry"
Microchem. J. 1989 Volume 40, Issue 2 Pages 233-241
Carbonell, V.;De La Guardia, M.;Salvador, A.;Burguera, J.L.;Burguera, M.

Abstract: Means of improving sensitivity of flow injection AAS systems are discussed, including use of T-connector interfaces, different carriers and flow compensation solvents. The optimized system was applied in the determination of Mn and Cu in sewage sludge.
Copper Manganese Spectrophotometry Optimization Sensitivity Interface Nebulizer

"Speciation Of Calcium By Flame Atomic Absorption Spectrometry Using Slurries"
Analusis 1991 Volume 19, Issue 7 Pages 213-217
Martinez Avila, R.;Salvador, A.;De La Guardia, M.

Abstract: Divalent calcium ion and solid Ca3(PO4)2 (I) are determined simultaneously in a single slurry sample (dispersed solid size of 6.3 to 20.5 m) by flame AAS at 422.7 nm with use of an air - acetylene or N2O - acetylene flame and La as an interference buffer. Results are interpreted from two separate calibration plots for dissolved Ca2+ and I, and an equation relating measured absorbance to the intercept and slope of the individual calibration plots and the concentration. of both forms of Ca is presented. Lower limits of detection were obtained with the N2O - acetylene flame, e.g., 0.02 and 0.03 mg L-1 for Ca2+ and I, respectively; the air - acetylene flame was more sensitive (0.048 and 0.028 absorbance units (mg mL-1)-1 for Ca2+ and I. For both flames, the coefficient of variation was 1% for Ca2+ and 3% for I. Results for synthetic samples are reported.
Calcium Iron Lead Manganese Spectrophotometry Slurry Speciation

"Slurries Introduction In Flow Injection Atomic Absorption Spectroscopic Analysis Of Sewage Sludges"
J. AOAC Int. 1990 Volume 73, Issue 3 Pages 389-393
Martinez-Avila, R.; Carbonell, V.; Guardia, M. de la; Salvador, A

Abstract: The effects were studied of flow injection parameters on the determination of Cu, Mn and Pb in sewage sludge, by injection of a sample into a carrier stream and detection by air - acetylene flame AAS. Samples were pre-digested with HNO3 with heating in a microwave oven. AAS instrumental parameters are given for each metal. The limits of detection were 0.06, 0.05 and 0.3 ppm, respectively, which are adequate for analysis of real samples. The method was applied to two reference materials; accuracy was better than that obtained by continuous aspiration.
Copper Manganese Lead Spectrophotometry Sample preparation Slurry Detection limit Reference material

"Microcomputers In A Water Authority Laboratory"
J. Autom. Methods Manag. Chem. 1985 Volume 7, Issue 4 Pages 192-196

Abstract: The microcomputer-based system (designated LABDAPS) described is currently in use in five laboratories that are engaged in monitoring the quality of river water, drinking water and sewage and trade effluents. The system can process data from, e.g., measurement of BOD and suspended solids and from AAS and continuous-flow analyzes; the individual microcomputers are linked to a central computer.

"Using FIMS To Determine Mercury Content In Sewage Sludge, Sediment And Soil Samples"
J. Autom. Methods Manag. Chem. 1996 Volume 18, Issue 6 Pages 221-223

Abstract: Sewage sludge (0.01 g) spiked with Hg was weighed into a digestion flask, moistened with a few drops of water and 21 mL HCl and 7 mL HNO3 were added. Digestion was carried out in accordance with DIN 38414, Part 12. The cooled solution was diluted to 100 mL with water. A portion (100 µL) of 0.5% K2Cr2O7 in HNO3/H2O (1:1) was added to 1 mL supernatant and the mixture was diluted to 10 mL. Samples were reduced with 1.5% SnCl2 in 1% HCl prior to Flow injection Mercury Systems (FIMS) analysis. Recoveries of Hg in spiked sewage sludge were 96-100% and analyzes of standard reference samples were in agreement with certified values. RSD (n = 3) were ~2% for 10 µg/l of Hg. Results obtained by FIMS were in agreement with values obtained by FIA generation of Hg vapor and AAS.
Mercury Spectrophotometry Sample preparation FIMS Volatile generation Method comparison Reference material Volatile generation

"Mercury Determination By CV-AAS In Wastewater And Sewage Sludge From A Stabilization Pond System"
Fresenius J. Anal. Chem. 1996 Volume 355, Issue 3-4 Pages 319-320
Katiuska Araujo, Marinela Colina, Román Mazurek, José Delgado, Hilda Ledo, Elizabeth Gutierrez and Lenín Herrera

Abstract: The mercury concentrations in wastewater and sewage sludge of a stabilization pond system have been evaluated. The system is built by three parallel facultative ponds followed by two systems of three maturation ponds in series. The samples of wastewater and sludge were digested using nitric acid and placed into a Parr-type bomb for 4 h at 110°C. Mercury was measured by Cold Vapour Atomic Absorption Spectrometry (CV-AAS) at 253.7 nm with sodium tetrahydroborate as reductant. The methodologies were checked with an USEPA quality control sample, a standard reference material from NIST and with another method of mineralization (cold mineralization) showing good results. Concentrations of mercury in wastewater between 1.47 ± 0.75 µg L-1 have been found at the entrance of the system and 0.74 ± 0.0 µg L-1 at the exit, while in sludge the results were between 0.29 ± 0.12 µg kg-1 in the facultative pond and 0.04 ± 0.02 µg kg-1 in the second maturation pond (exit).
Mercury Spectrophotometry Method comparison Reference material