Talanta Determination of chloride in admixtures and aggregates for ...

368 J. Junsomboon, J. Jakmunee / Talanta 76 (2008) 365–368or Y = 96.5X − 16.1 (r 2 = 0.989), respectively, were obtained. However,these ions are usually present in the sample at relativelylow concentrations compared to Cl − and do not significantlyinterfere.3.3. Application to real samplesThe system was applied to cement aggregate and admixturesamples. The samples were prepared as described in Section 2.4.The contents of Cl − in the samples were calculated using a calibrationgraph (Y =57.6X − 23.3, r 2 = 0.9994) and were found in rangeof 8–113 mg L −1 , which were converted to % (w/w) of Cl − in samplesas summarized in Table 2. The analysis of aggregate samples bytitrimetric standard method [2] and admixture samples by potentiometrictitration standard method [3] was also carried out forcomparison. The standard methods are applied for determinationof total halides, except F − , reported as Cl − content. The Cl − contentsobtained from the proposed method were in good agreementwith those from the standard methods, evaluating by t-test at 95%confidence level [20]. It should be noted that the proposed methodhas lower detection limit (0.0002%, w/w), so it can determine lowerlevelofCl − in samples with good precision. It is also faster and consumedsmaller amounts of reagents. The permission level of Cl − inconcrete admixtures by Thai Industrial Standard (TIS 733–2530) is0.20 ± 0.01%, while British Standard is 0.10%. The application of themethod could be extended to analysis of water used in preparingof cement.4. ConclusionA simple Cl − ISE and FI potentiometric method have beendeveloped for the determination of water soluble Cl − content inaggregates and admixtures for concrete. In comparison to the standardmethods, the developed method provided agreeable results,moreover it is lower cost, lower reagent consumption, fasterand has lower detection limit. The system gave linear range of10–100 mg L −1 Cl − , detection limit of 2 mg L −1 Cl − , relative standarddeviation of 0.6–1.2% and sample throughput of 60 h −1 ,whicharecomparable to the previous flow based systems, but with simplerin instrumentation and no use of toxic or expensive chemicals.AcknowledgementsWe thank the Center for Innovation in Chemistry: PostgraduateEducation and Research Program in Chemistry (PERCH-CIC), theCommission on Higher Education (CHE) and the Thailand ResearchFund (TRF) for financial support.References[1] http://en.wikipedia.org/wiki/Reinforced concrete (access on 26/1/2008).[2] British Standard: testing aggregates, Part 117: method for determination ofwater soluble chloride salts (BS 812: Part 117: 1988, Method A), British StandardInstitution, 1988.[3] British Standard: admixtures for concrete, mortar and grout – Test Methods– Part 10: determination of water soluble chloride content (BS EN 480 – 10:1997), British Standard Institution, 1997.[4] J.F. Liu, Y.D. Feng, G.B. Jiang, J. AOAC Int. 84 (2001) 1179.[5] J.F. Liu, G.B. Jiang, Talanta 54 (2001) 329.[6] J.F. van Staden, S.I. Tlowana, Fresenius J. Anal. Chem. 371 (2001) 396.[7] C.R. Silva, H.J. Vieira, L.S. Canaes, J.A. Nobrega, O. Fatibello-Filho, Talanta 65(2005) 965.[8] F. Maya, J.M. Estela, V. Cerda, Talanta 74 (2008) 1534.[9] R.B.R. Mesquita, S.M.V. Fernandes, A. Rangel, J. Environ. Monitor. 4 (2002) 458.[10] M. Zenki, Y. Iwadou, Talanta 58 (2002) 1055.[11] V.G. Bonifacio, L.C. Figueiredo-Filho, L.H. Marcolino, O. Fatibello-Filho, Talanta72 (2007) 663.[12] A. Andrade-Eiroa, J.A. Erustes, R. Forteza, V. Cerda, J. Lima, Anal. Chim. Acta 467(2002) 25.[13] A.M. Pimenta, A.N. Araujo, M. Conceição, B.S.M. Montenegro, C. Pasquini,J.J.R. Rohwedder, I.M. Raimundo-Júnior, J. Pharm. Biomed. Anal. 36 (2004)49.[14] J.E. da Silva, M.F. Pimentel, V.L. da Silva, M.D. Montenegro, A.N. Araujo, Anal.Chim. Acta 506 (2004) 197.[15] A.N. Araujo, M. Montenegro, L. Kousalova, H. Sklenarova, P. Solich, R.P. Olmos,Anal. Chim. Acta 505 (2004) 161.[16] I.S. da Silva, E.M. Richter, C.L. do Lago, I.G.R. Gutz, A.A. Tanaka, L. Angnes, Talanta67 (2005) 651.[17] J. Jakmunee, L. Patimapornlert, S. Suteerapataranon, N. Lenghor, K. Grudpan,Talanta 65 (2005) 789.[18] W. Frenzel, Fresenius J. Anal. Chem. 335 (1989) 931.[19] T. Altunbulduk, H. Meier zu Koecker, W. Frenzel, Fresenius J. Anal. Chem. 351(1995) 593.[20] G.D. Christian, Analytical Chemistry, 6th ed., Wiley, New York, USA, 2004.