Cloud point extraction (CPE) has been used for the preconcentration of cadmium, after the formation of a complex with 1, 5-bis(di-2-pyridylmethylene) thiocarbonohydrazide (DPTH), and further determination by flame atomic absorption spectrometry (FAAS) using Triton X-114 as surfactant. The main factors affecting the CPE, such as concentration of Triton X-114 and DPTH, pH, equilibration temperature and incubation time, were optimized for the best extract efficiency. Under the optimum conditions i.e., pH 5.4, [DPTH] = 6x10-3%, [Triton X-114] = 0.25% (v/v), an enhancement factor of 10.5 fold was reached. The lower limit of detection (LOD) obtained under the optimal conditions was 0.95 μg L?1. The precision for 8 replicate deter- minations at 20 and 100 μgL?1 Cd were 2.4 % and 2 % relative standard deviation (R.S.D.). The calibration graph using the preconcentration method was linear with a correlation coefficient of 0,998 at levels close to the detection limit up to at least 200 μgL?1. The method was successfully applied to the determination of cadmium in water, environmental and food samples and in a BCR-176 standard reference material.
KeywordsCadmiumFlame Atomic Absorption SpectrometryCloud Point ExtractionTriton X-114Water SamplesFood Samples
A. C. Davis, P. Wu, X. F. Zhang, X. D. Hou and B. T. Jones, “Determination of Cadmium in Biological Sam- ples,” Applied Spectroscopy Reviews, Vol. 41, No. 1, 2006, pp. 35-75.
S. Arce, S. Cerutti, R. Olsina, M. R. Gomez and L. D. Martinez, “Trace Element Profile of a Wild Edible Mushroom (Suillus Granulatus),” Journal of Association of Official Analytical Chemists International, Vol. 91, No. 4, 2008, pp. 853-857.
M. W. Ashraf and S. Akram, “Physicochemical Charac- teristics and Heavy Metal Contents of Saudi Arabian Floral Honeys,” Fresenius Environmental Bulletin, Vol. 17, No. 7b, 2008, pp. 877-881.
S. L. C. Ferreira, J. B. Andrade, M. G. A. Korn, M. G. Pereira, V. A. Lemos, W. N. L. dos Santos, F. M. Rodri- gues, A. S. Souza, H. S. Ferreira and E. G. P. da Silva, “Review of Procedures Involving Separation and Preconcentration for the Determination of Cadmium Us- ing Spectrometric Techniques,” Journal of Hazardous Materials, Vol. 145, No. 3, 2007, pp. 358-367.
M. A. Bezerra, M. A. Z. Arruda and S. L. C. Ferreira, “Cloud Point Extraction as a Procedure of Separation and Préconcentration for Metals Determination Using Spec- troanalytical Techniques: A Review,” Applied Spectros- copy Reviews, Vol. 40, No. 4, 2005, pp. 269-299.
C. B. Ojeda and F. S. Rojas, “Separation and Preconcen- tration by a Cloud Point Extraction Procedure for Deter- mination of Metals: An Overview,” Analytical and Bio- analytical Chemistry, Vol. 394, No. 3, 2009, pp. 759-782.
C. G. Pinto, J. L. P. Pavón, B. M. Cordero and E. R. Beato, “Cloud Point Preconcentration and Flame Atomic Absorption Spectrometry: Application to the Determina- tion of Cadmium,” Journal of Analytical Atomic Spec- trometry, Vol. 11, No. 1, 1996, pp. 37-41.
M. A. M. da Silva, V. L. A. Frescura and A. J. Curtius, “Determination of Trace Elements in Water Samples by Ultrasonic Nebulization Inductively Coupled Plasma Mass Spectrometry after Cloud Point Extraction,” Spec- trochimica Acta B, Vol. 55, No. 7, 2000, pp. 803-813.
J. Chen and K. C. Teo, “Determination of Cadmium, Copper, Lead and Zinc in Water Samples by Flame Atomic Absorption Spectrometry after Cloud Point Ex- traction,” Analytica Chimica Acta, Vol. 450, No. 1, 2001, pp. 215-222.
J. L. Manzoori and A. T. Bavili, “Cloud Point Preconcen- tration and Flame Atomic Absorption Spectrometric De- termination of Cd and Pb in Human Hair,” Analytica Chimica Acta, Vol. 470, No. 2, 2002, pp. 215-221.
J. L. Manzoori and G. Karim-Nezhad, “Development of a Cloud Point Extraction and Preconcentration Method for Cd and Ni Prior to Flame Atomic Absorption Spectro- metric Determination,” Analytica Chimica Acta, Vol. 521, No. 2, 2004, pp. 173-177.
C. G. Yuan, G. B. Jiang, Y. Q. Cai, B. He and J. F. Liu, “Determination of Cadmium at the Nanogram per Liter Level in Seawater by Graphite Furnace AAS Using Cloud Point Extraction,” Atomic Spectroscopy, Vol. 25, No. 4, 2004, pp. 170-176.
L. M. Coelho and M. A. Z. Arruda, “Preconcentration Procedure Using Cloud Point Extraction in the Presence of Electrolyte for Cadmium Determination by Flame Atomic Absorption Spectrometry,” Spectrochimica Acta B, Vol. 60, No. 5, 2005, pp. 743-748.
T. A. Maranh?o, D. L. G. Borges, M. A. S. da Veiga and A. J. Curtius, “Cloud Point Extraction for the Determination of Cadmium and Lead in Biological Samples by Graphite Furnace Atomic Absorption Spectrometry,” Spectro- chimica Acta B, Vol. 60, No. 5, 2005, pp. 667-672.
P. Liang, J. Li and X. Yang, “Cloud Point Extraction Preconcentration of Trace Cadmium as 1-Phenyl-3- methyl-4-benzoyl-5-pyrazolone Complex and Determi- nation by Flame Atomic Absorption Spectrometry,” Mi- crochimica Acta, Vol. 152, No. 1-2, 2005, pp. 47-51.
A. Afkhami, T. Madrakian and H. Siampour, “Flame Atomic Absorption Spectrometric Determination of Trace Quantities of Cadmium in Water Simples after Cloud Point Extraction in Triton X-114 without Added Chelat- ing Agents,” Journal of Hazardous Materials, Vol. 138, 2006, pp. 269-272.
P. Wu, Y. Zhang, Y. Lv and X. Hou, “Cloud Point Extraction—Thermospray Flame Quartz Furnace Atomic Absorption Spectrometry for Determination of Ultratrace Cadmium in Water and Urine,” Spectrochimica Acta B, Vol. 61, No. 12, 2006, pp. 1310-1314.
J. L. Manzoori, H. Abdolmohammad-Zadeh and M. Am- jadi, “Ultratrace Determination of Cadmium by Cold Vapor Atomic Absorption Spectrometry after Preconcentration with a Simplified Cloud Point Extraction Methodology,” Talanta, Vol. 71, No. 2, 2007, pp. 582-587.
X. S. Zhu, X. H. Zhu and B. S. Wang, “Determination of Trace Cadmium in Water Samples by Graphite Furnace Atomic Absorption Spectrometry after Cloud Point Ex- traction,” Microchimica Acta, Vol. 154, No. 1-2, 2006, pp. 95-100.
S. Xiao, J. Chen, X. Wu and Y. Miao, “Determination of Cadmium in Water Samples by Graphite Furnace Atomic Absorption Spectrometry after Cloud Point Extraction,” Journal of Analytical Chemistry, Vol. 62, No. 1, 2007, pp. 42-45.
P. R. Aranda, R. A. Gil, S. Moyano, I. De Vito and L. D. Martinez, “Cloud Point Extraction for Ultra-Trace Cd Determination in Microwave-Digested Biological Samples by ETAAS,” Talanta, Vol. 77, No. 2, 2008, pp. 663-666.
G. L. Donati, K. E. Pharr, C. P. Calloway Jr., J. A. Nóbrega and B. T. Jones, “Determination of Cd in Urine by Cloud Point Extraction—Tungsten Coil Atomic Absorption Spec- trometry,” Talanta, Vol. 76, No. 5, 2008, pp. 1252-1255.
H. Filik, F. Dondurmacioglu and R. Apak, “Micelle Me- diated Extraction of Cadmium from Water and Tobacco Samples with Glyoxal-bis(2-hydroxyanil) and Determi- nation by Electrothermal Atomic Absorption Spectrome- try,” International Journal of Environmental Analytical Chemistry, Vol. 88, No. 9, 2008, pp. 637-648.
V. A. Doroshchuk and S. A. Kulichenko, “Preconcentra- tion of Cadmium with OP-10 Nonionic Surfactant Phases at the Cloud Point,” Journal of Analytical Chemistry, Vol. 60, No. 5, 2005, pp. 400-403.
T. D. A. Maranh?o, E. Martendal, D. L. G. Borges, E. Carasek, B. Welz and A. J. Curtius, “Cloud Point Extraction for the Determination of Lead and Cadmium in Urine by Graphite Furnace Atomic Absorption Spectrometry with Multivariate Optimization Using Box—Behnken Design,” Spectrochimica Acta B, Vol. 62, No. 9, 2007, pp. 1019-1027.
L. A. Portugal, H. S. Ferreira, W. N. L. Santos and S. L. C. Ferreira, “Simultaneous Pre-Concentration Procedure for the Determination of Cadmium and Lead in Drinking Water Employing Sequential Multi-Element Flame Atomic Absorption Spectrometry,” Microchemical Jour- nal, Vol. 87, No. 1, 2007, pp. 77-80.
S. M. Talebi, S. Habib-Ollahi and A. Semnani, “Cloud Point Extraction and Flame Atomic Absorption Spec- trometric Determination of Lead and Cadmium in Natural Waters,” Asian Journal of Chemistry, Vol. 19, 2007, pp. 2445-2451.
E. L. Silva and P. dos S. Roldán, “Simultaneous Flow Injection Preconcentration of Lead and Cadmium Using Cloud Point Extraction and Determination by Atomic Absorption Spectrometry,” Journal of Hazardous Mate- rials, Vol. 161, No. 1, 2009, pp. 142-147.
S. D. Abkenar, M. Hosseini and M. Salavati-Niasari, “Cloud Point Extraction and Preconcentration of Silver and Cadmium Using Schiff Base Prior to Flame Atomic Absorption Spectrometric Determination,” Asian Journal of Chemistry, Vol. 20, No. 6, 2008, pp. 4291-4300.
M. Arvand, A. Pourhabib, A. Afshari, M. Bagherinia, N. Ghodsi and R. J. Shemshadi, “Determination of Cad- mium and Zinc in Water Samples by Flame Atomic Ab- sorption Spectrometry after Cloud-Point Extraction,” Jour- nal of Analytical Chemistry, Vol. 63, No. 10, 2008, pp. 954-959.
E. L. Silva, P. S. Roldan and M. F. Giné, “Simultaneous Preconcentration of Copper, Zinc, Cadmium, and Nickel in Water Samples by Cloud Point Extraction Using 4-(2- Pyridylazo)-Resorcinol and Their Determination by In- ductively Coupled Plasma Optic Emission Spectrome- try,” Journal of Hazardous Materials, Vol. 171, No. 1-3, 2009, pp. 1133-1138.
M. Ghaedi, A. Shokrollahi, K. Niknam, E. Niknam, A. Najibi and M. Soylak, “Cloud Point Extraction and Flame Atomic Absorption Spectrometric Determination of Cadmium(II), Lead(II), Palladium(II) and Silver(I) in En- vironmental Samples,” Journal of Hazardous Materials, Vol. 168, No. 2-3, 2009, pp. 1022-1027.
M. C. Talio, M. O. Luconi, A. N. Masi and L. P. Fernández, “Determination of Cadmium at Ultra-Trace Level by CPE-Molecular Fluorescence Combined Methodology,” Journal of Hazardous Materials, Vol. 170, No. 1, 2009, pp. 272-277.
X. Wen, P. Wu, L. Chen and X. Hou, “Determination of Cadmium in Rice and Water by Tungsten Coil Electro- thermal Vaporization-Atomic Fluorescence Spectrometry and Tungsten Coil Electrothermal Atomic Absorption Spectrometry after Cloud Point Extraction,” Analytica Chimica Acta, Vol. 650, No. 1, 2009, pp. 33-38.