Acta Chim. Slov. 2003, 50, 807-814. 807 PRECONCENTRATION OF Cu (II), Fe(III), Ni(II), Co(II) AND Pb(II) IONS IN SOME MANGANESE SALTS WITH SOLID PHASE EXTRACTION METHOD USING CHROMOSORB-102 RESIN Sibel Saracoglu* Erciyes University, Faculty of Education, 38039 Kayseri-TURKEY. E-mail: saracs@erciyes.edu.tr Mustafa Soylak Erciyes University, Faculty of Art and Science, Department of Chemistry, 38039 Kayseri-TURKEY Latif Elci Pamukkale University, Faculty of Art and Science, Department of Chemistry, 20020, Denizli-TURKEY Received 22-03-2003 Abstract An enrichment/separation procedure for the atomic absorption spectrometric determinations of Cu (II), Fe(III), Ni(II), Co(II) and Pb(II) ions in Mn(N03)2 and KM11O4 has been established. The ammonium pyrrolidinedithiocarbamate (APDC) complexes of the analyte ions were adsorbed on the Chromosorb-102 column and then desorbed with 10 mL acetone. The effects of manganese concentrations as interferent were discussed. The method has been successfully applied to the determination of Cu, Fe, Ni, Co and Pb in analytical reagent grade manganese salts. Under optimized conditions, the recovery values were > 95%. The relative standard deviations (n=5) with related to the determinations in the Mn(N03)2 and KM11O4 was in the range of 1-9% and 6-14%, respectively. Introduction Metallic manganese of relatively pure grade is the basic material for a series of alloys with special electrical and thermal characteristics. Impurities are generally in the range of ppm and less. Of different manganese compounds, Mn(N03)2.4H20 and M11O2 are of particular technical importance. For this reason, the quantitative determination of impurities in these compounds is important. The direct determination of metal impurities by fiame atomic absorption spectrometer (FAAS) in analytical reagent-grade salts is often difficult or even impossible because of their low levels and matrix effects. For this reason, a preconcentration and separation procedure is required. In trace element analysis, S. Saracoglu, M. Soylak, L. Elci: Preconcentration of Cu(II), Fe(III), Ni(II), Co(II), and Pb(II) Ions... 808 Acta Chim. Slov. 2003, 50, 807-814. preconcentration and separation methods also enhance the sensitivity and precision of the determination. Separation and preconcentration techniques such as adsorption, membrane filtration, cloud point extraction, solvent extraction and coprecipitation have been carried out. " Among these techniques used in trace element preconcentration, solid phase extraction is an attractive technique based on the use of a sorbent that retains the analytes. The retained analytes are eluted from the sorbent using relatively small volume of a suitable solvent. This feature provides a high analvtical preconcentration factor for large volume samples. Various sorbents such as Amberlite XAD resins, " silicagel, C-18, " activated carbon " etc. have been used for the solid phase extraction of metal ions from the different matrices. Chromosorb resins are svnthetic polvmeric materials ' and have been used in gas chromatographv as stationary phases, because they have good physical and chemical properties such as porosity, high surface area, durability and purity and are resistant in concentrated mineral acid, concentrated bases and organic solvents for a long tirne. Chromosorb-102 resin is an adsorbent based on polystyrene divinvl benzene copolymer having hydrophobic character. It has been widely used as adsorbents suitable in gas chromatographic separation of organic compounds. ' Chromosorb resins have been used for the preconcentration of traces heavy metal ions in various samples. Ammonium pyrrolidinedithiocarbamate (APDC) as a chelating reagent in solid phase extraction method has been widely applied to the preconcentration of trace metals, prior to their determination by AAS. This paper presents a separation/preconcentration procedure for ammonium pyrrolidinedithiocarbamate (APDC) complexes of some trace metal ions in some manganese salts on a column filled with Chromosorb-102 adsorption resin prior to their flame atomic absorption spectrometric determinations. Experimental Apparatus A Perkin Elmer Model 3110 atomic absorption spectrometer was used for determination of metals. Ali measurements were carried out in air/acetylene flame and without background correction. The instrumental parameters were set as recommend by S. Saracoglu, M. Soylak, L. Elci: Preconcentration of Cu(II), Fe(III), Ni(II), Co(II), and Pb(II) Ions... Acta Chim. Slov. 2003, 50, 807-814. 809 the manufacturer. pH measurements were performed with a Nel pH 900 digital pH meter and combined glass electrode. Reagents Analytical reagent-grade chemicals were employed for the preparation of ali solutions. Doubly distilled water was used in ali experiments. Metal stock solutions of the working elements (1000 mg/L) were prepared by dissolving their respective nitrates in 1% HNO3. The stock solutions of the analytes were standardized by titrimetrically. Working standard solutions were prepared in 1 M HNO3 by diluting just prior to use. Acetone used for elution, concentrated hydrochloric and nitric acids, Mn(N03)2 and KMnC>4 from Merck, Darmstadt in extrapure quality. An ammonium pyrrolidinedithiocarbamate (APDC) solution, 0.05%, was prepared by dissolving the required amount of APDC in water immediately before use. Resin and Column Preparation The Chromosorb-102 resin (Phase Separations, 750 614) having a surface area of 300-400 m /g and a particle size of 80-100 mesh was used as solid phase. A 500 mg Chromosorb-102 resin suspended in water was slurry packed into a glass column (10 mm id x 100 mm length, height of the resin approximately 15 mm). It was washed successively with water, acetone and water, respectively. Before the use, the column was preconditioned with 5-10 mL of blank solution. After each experiment, the resin in the column was washed with large volumes of water. Procedure for Preconcentration The performance of column method was tested with model solution prior to its application to manganese salts. For this, 25 mL of the model solution containing 10 µg each of Cu, Fe, Co and Ni and 20 µg Pb was buffered to the desired pH. Three millilitres of 0.05% (w/v) APDC solution was added to form the metal-APDC chelates. The sample solution was permitted to flow through the column under gravity at the flow rate of 5 mL/min. After passage of the solution finished; the column was washed with a blank solution. The retained analyte ions were eluted from the Chromosorb-102 column by 10 mL of acetone at flow rate of 7.5 mL/min. The eluate was evaporated to -1-2 mL S. Saracoglu, M. Soylak, L. Elci: Preconcentration of Cu(II), Fe(III), Ni(II), Co(II), and Pb(II) Ions... 810 Acta Chim. Slov. 2003, 50, 807-814. on a hot plate in a hood. The solution was transferred into a 2-10 mL volumetric flask with 1 M HNO3 solution. The analyte ions in the final solution were determined by FAAS. Analysis of Manganese Salts For the analysis of analyte ions contents of manganese nitrate, 3.000 g Mn(N03)2.4H20 was dissolved in 100 mL water. Then the preconcentration procedure given above was applied. Prior to the analysis of KMn04, the reduction of KMnC>4 was necessary because of decomposing of Chromosorb 102 resin structure by KMn04. For the reduction of Mn(VII) to Mn(II), sodium oxalate was used. 1.000-1.500 g of KMnC>4 was reduced with 90 mL of 0.2 M Na2C2C>4 in 1 M H2SO4. The solution was neutralized with 6 M NH3. Then the preconcentration procedure given above was applied to this solution. The analvtes ions were determined by FAAS. Results and discussion Recently, it has been explained that the determination of some trace metal ions in various samples could be performed after separation and preconcentration by sorbing the metal-APDC complexes on the Chromosorb-102 column. In this study, the Chromosorb-102 column method has been modified for the separation/preconcentration of trace metal ions in manganese salts. The optimum conditions for the preconcentration method are given Table 1. The analvte ions were quantitatively recovered at pH range of 4-7. The volume of the buffer solution (10 mL) has not any effect on the recoveries. 1.5 mg of APDC and 500 mg of Chromorb-102 was used in ali experiments. The analvte ions were quantitatively recovered in the sample volume range of 25-600 mL. Quantitative recoveries of the analyte ions were obtained by using 10 mL of acetone at 7.5 mL/min flow rate. The detection limit was calculated after presented preconcentration procedure applied to 50 mL of the blank solutions. The detection limit for analyte ions based on three times the standard deviations of the blank were in the range of 0.009 µg/g for Cu-0.22 µg/g for Fe (N=20). These results are comparable with the results in reference 25. S. Saracoglu, M. Soylak, L. Elci: Preconcentration of Cu(II), Fe(III), Ni(II), Co(II), and Pb(II) Ions... Acta Chim. Slov. 2003, 50, 807-814. 811 Table 1. The Effect of Some Parameters on the Recovery with APDC of Trace Elements with Solid Phase Extraction Method Using Chromosorb 102 Resin. Parameters Investigated Range Best values pH of Sample Solution 1-10 6 Amount of Chromosorb-102 300-700 mg 500 mg Amount of APDC 0.5-5 mg 1.5 mg Types of Eluent Acetone, 1 M HNO3 in acetone, 1 M HNO3, 1 M HCl Acetone Volume of Eluent 5-15 mL 10 mL Flow Rate of Eluent 1-10 mL/min 5 mL/min Flow Rate of Sample 2-12 mL/min 7.5 mL/min Matrix Effects The recoveries were quantitative for Cu (H), Fe(III), Ni(II), Co(II) and Pb(II) in optimum conditions using APDC as a chelating reagent, however the recoveries of Mn(II) was smaller than 5%. For this reason, preconcentration and separation of analvte ions from manganese salts was examined. In order to investigate the effect of manganese concentrations on the recoveries of the examined elements, the procedure has been carried out with 100 mL of sample solutions containing different amounts of Mn(II). The results are given in Table 2. The retentions of investigated analvte ions were not affected by manganese concentrations as Mn(N03)2.4H20 set up to 7500 mg/L Mn (II). Table 2. The Effect of Manganese Concentrations on Recoverv of Analvte Ions (N=3). Recovery,% Mn(N03)2.4H20 KMn04 Conc. of Mn, mg/L Cu Fe Co Ni Pb 2500 95 100 95 95 100 5000 95 100 95 100 99 7500 96 95 93 100 100 10000 89 61 86 100 100 1000 96 98 96 95 100 2000 95 94 92 98 97 4000 97 95 96 98 100 The effect of the Mn (VE) on the recoveries of analvtes was also investigated. The resin was decomposed by the addition of the permanganate solution. Due to this, the preconcentration procedure was applied to the permanganate solutions after reduction of S. Saracoglu, M. Soylak, L. Elci: Preconcentration of Cu(II), Fe(III), Ni(II), Co(II), and Pb(II) Ions... 812 Acta Chim. Slov. 2003, 50, 807-814. Mn(VII) to Mn(II) by sodium oxalate. We have found that there is no effect of oxalate ions on preconcentration of the examined analytes. The quantitative recovery values were obtained with 90 mL of 0.2 M Na2C2C»4 in 1 M H2SO4. As can be seen from Table 2 in the working range of Mn from 1000 to 4000 mg/L as KMnC^, the recoveries of examined analytes were quantitative. According to these data, it can be concluded that Cu (II), Fe(III), Ni(II), Co(II) and Pb(II) in Mn(N03)2 and KMn04 can be determined by the preconcentration procedure proposed. Analytical Performance of the Method The accuracy of the procedure was confirmed by the recoveries of spikes from Mn(N03)2.4H20 (Mn content is 7500 mg/L). The results were given in Table 3. Quantitative recoveries of different amounts of the investigated metal ions spikes were obtained. Thus, confirming the accuracy of the procedure and its independence from the matrix effects. Table 3. The Recoveries of Metal Ions in Manganese (II) Nitrate (Merck) (Volume of Sample: 100 mL, N=3). Element Added, µg Found, µg Recovery,% Cu 0 3.8 - 3.0 6.6 93 5.0 8.6 96 Fe 0 8.9 - 5.0 13.7 96 20.0 28.7 99 Co 0 0.7 - 0.5 1.2 100 1.0 1.6 90 Ni 0 4.1 - 3.0 7.2 103 5.0 8.9 96 Pb 0 3.8 - 2.0 5.7 95 4.0 7.4 90 S. Saracoglu, M. Soylak, L. Elci: Preconcentration of Cu(II), Fe(III), Ni(II), Co(II), and Pb(II) Ions... Acta Chim. Slov. 2003, 50, 807-814. 813 Applications The proposed method was applied to the determination of Cu, Fe, Co, Ni and Pb ions in analytical reagent grade Mn(N03)2.4H20 and KMnC>4. The levels of the investigated ions are given in Table 4. The results have been calculated on the assumption of 100% recovery of metal ions. The concentrations of Cu, Fe, Co, Ni and Pb in manganese (II) nitrate were less than the contents guarantied by the distributor of the reagents. The concentration of Pb in potassium permanganate was below the detection limit. The relative standard deviations (n=5) with related to the determinations in the Mn(N03)2 and KMn04 was in the range of 1-9% and 6-14%, respectively. Table 4. Concentrations of Metal Ions in Manganese (II) Nitrate and Potassium Permanganate (N=5). Concentration (µg/g)* Sample Cu Fe Co Ni Pb Mn(N03)2 1.10 ± 0.06 2.72 ± 0.37 0.20 ± 0.01 1.21 ± 0.04 1.07 ± 0.10 KMn04 2.54 ± 0.29 9.29 ± 0.64 0.42 ± 0.06 2.74 ± 0.49 BDL * P=0.05, ± ts?N, BDL: Below the limit of detection. Conclusions The proposed column preconcentration method provides a simple, sensitive, accurate and selective method for the preconcentration and separation of investigated analvte ions in manganese salts. The precision and recovery (>95%) were satisfactory. The proposed method can be used for the preconcentration and separation of traces of Cu (H), Fe(III), Ni(II), Co(II) and Pb(II) ions in the other matrices, such as natural water samples and geological materials, etc. The present method is promising for enrichment of analvte ions with the preconcentration factor of 50 and is superior to those reported in the literature 26-30. The vvorking pH range (4-7) for ali the metal ions is slightly acidic and therefore there is no possibility of their hydrolysis. The effects of manganese salts investigated as matrix for the analyte ions were reasonably tolerable. The relative standard deviations of the determinations were lower comparing to other methods. ' ' " Also the apparatus used in the experiments is simple. S. Saracoglu, M. Soylak, L. Elci: Preconcentration of Cu(II), Fe(III), Ni(II), Co(II), and Pb(II) Ions... 814 Acta Chim. Slov. 2003, 50, 807-814. Acknowledgements The authors would like to thank TÜBITAK (the Scientific and Technical Research Council of Turkey) for providing the Perkin-Elmer 3110 atomic absorption spectrometer used in the present study. References 1. A. Mizuike, Enrichment Techniques of Trace Analysis, 1983, Springer, Berlin. 2. J. L. Manzoori, A. Bavili-Tabrizi, Microchim. Acta 2003, 141, 201–207. 3. Y. Yamini, A. Tamaddon, Talanta 1999, 49, 119–124. 4. L. Elci, Z. Arslan, J. F. Tyson, Spectrochim. Acta 2000, 55B, 1109–1116. 5. A. F. S. Junior, M. G.A . Korn, H. V. Jaeger, N. M. S. Silva, A. C. S. Costa, Quim. Nova 2002, 25, 1086–1090. 6. M. Soylak, A. U. Karatepe, L. Elci, M. Dogan, Turk. J. Chem. 2003, 27, 235–242. 7. S. Saracoglu, M. Soylak, L. Elci, Trace Elem. Electrolyt. 2001, 18, 129–133. 8. A. R. Turker, A. Tunceli, Fresen. J. Anal. Chem. 1993, 345, 755–758. 9. M. G. Pereira, M. A. Z. Arruda, Microchim. Acta 2003, 141, 115–131. 10. G. M. Wuilloud, R. G. Wuilloud, J. C. A. Wuilloud, R. A. Olsina, L. D. Martinez, J. Pharmaceut. Biomed. 2003, 31, 117–124. 11. B. S. Garg, J. S. Bist, R. K. Sharma, N. Bhojak, Talanta 1996, 43, 2093–2099. 12. V. J. Leepipatpiboon, Chromatogr. 1995, 697A, 137–143. 13. A. Gaspar, J. Posta, Fresen. J. Anal. Chem. 1998, 360, 179–183. 14. H. Ji, Z. Liao, J. Sun, Z. Jiang, Fresen. J. Anal. Chem. 1998, 360, 721–723. 15. H. Cesur, M. Macit, B. Bati, Anal. Lett. 2000, 33, 1991–2004. 16. K. Nakagawa, K. Haraguchi, T. Ogata, T. Kato, Y. Nakata, K. Akatsuka, Anal. Sci. 1998, 14, 317–320. 17. T. C. Thomas, J. N. Seiber, Bull. Environ. Contam. Toxicol. 1974, 12, 17–21. 18. L. D. Butler, M. F. Burke, J. Chromatogr. Sci. 1976, 14, 117–126. 19. Y. Cai, G. B. Jiang, J. F. Liu, X. Liang, Atom. Spectr. 2002, 23, 52–58. 20. Y. Cai, G. Jiang, J. Liu, Talanta 2002, 57, 1173–1180. 21. Y. Ca, G. Jiang, J. Liu, B. He, Anal. Sci. 2002, 18, 705–707. 22. M. Soylak, S. Saraçoglu, L. Elçi, Bull. Korean Chem. Soc. 2003, 24, 555–558. 23. M. Kimura, K. Kawanami, Talanta 1979, 26, 901–903. 24. K. Anezaki, X. Chen, T. Ogasawara, I. Nukatsuka, K. Ohzeki, Anal. Sci. 1998, 14, 523–527. 25. S. Saracoglu, L. Elci, Anal. Chim. Acta 2002, 452, 77–83. 26. J. Basset, T. C. Denney, Vogel's Text-Book of Quantitative Inorganic Analysis, 1983, Longman, London. 27. Y. Bakircioglu, D. Bakircioglu, S. Akman, J. Trace Microprobe T. 2003, 21, 467–478. 28. M. Alkan, D. Kara, J. Trace Microprobe T. 2003, 21, 479–492. 29. S. Cerutti, R. F. Orsi, J. A. Casquez, R. A. Olsina, L. D. Martinez, J. Trace Microprobe T. 2003, 21, 421–432. 30. A. A. Ensafi, T. Khayamian, M. H. Karbasi, Anal. Sci. 2003, 19, 953–956. Povzetek Razvili smo postopek predkoncentriranja/separiranja za določitev Cu(II), Fe(II), Ni(II), Co(II) in Pb(II) z atomsko absorpcijsko spektrometrijo v Mn(NO3)2 in KMnO4. Komplekse določevanih ionov z amonijevim pirolidinditiokarbamatom (APDC) smo adsorbirali na koloni, napolnjeni z nosilcem Chromosorb-102, in desorbirali z 10 mL acetona. Preučili smo interference, ki jih povzroča mangan v različnih koncentracijah. Metodo smo uspešno uporabili za določitev Cu, Fe, Ni, Co in Pb v manganovih soleh čistosti p.a. Izkoristek pri optimiziranih pogojih je bil > 95%. Dobili smo relativne standardne odmike (n=5) v območju 1-9% za določevanje ionov v Mn(NO3)2 in 6-14% za KMnO4. S. Saracoglu, M. Soylak, L. Elci: Preconcentration of Cu(II), Fe(III), Ni(II), Co(II), and Pb(II) lons...