Determination of inorganic anions in red algae (Eucheuma cottonii ...

R. Suhaili et al. Proceeding of The International Seminar on Chemistry 2008 (pp. 406-410)Jatinangor, 30-31 October 2008Conductivity (µS/cm)600004000020000123 4 5651 2 3 4 6 7 800 5 10Figure 2 Chromatogram of anion separation a. Eucheuma cottonii, b. Anion Standard solution 0.3 mM. Flowrate of Na 2 CO 3 : NaHCO 3 [1.2:1.4 mM] 0.7 mL/min, Columns TSKgel IC-Anion PW XL (50x4.6 mmi.d). Column temperature: room temperature, Injection volume: 20 µL. Peak: 1. F - , 2. Cl - , 3. NO 2 - , 4.Br - , 5. NO 3 - , 6. HPO 4 - , 7. SO 4 = , 8. I -7Retention Time (min)8baTable 3 Anion contained in red algae (Eucheuma cottonii) and carragenanSamplePureCarrageenanExtractedCarrageenanEucheumacottoniiAnion contained mg/100gF - Cl - -NO 2 Br - -NO 32-HPO 42-SO 4 I -1.75 16.60 1.28 5.22 445.47 8.64 19.16 11.661.80 17.79 0.89 5.10 442.45 8.02 25.14 10.132.33 10.02 1.71 7.77 448.94 7.99 22.14 15.12Good separations for common inorganic anions wereachieved. Ion contain in sample is shown in Table 3.-Table 3 shown that the sample contains NO 3 as amain component in both red algae (Eucheumacottonii) and carragenan. The heigh concentration ofnitrate in samples is caused by red algae consumednitrate very rapidly due to light conditions [1].ConclusionsIn conclusion, an ion chromatographic system usingtwo 6-port switching valves and two packed columnsuppressors to maintain the suppressed conductivity,were used for continuous suppression to obtain bettersensitivity. Eight common inorganic anions (F - , Cl -,NO 2 - , Br - , NO 3 - , HPO 4 2- , SO 4 2- , I - ) could bedetermined by contactless conductivity detector. Themixture of 1.4 mM sodium bicarbonate and 1.2 mMsodium carbonate with flow rate 0.7 mL/min wassuitable for the determination of the above inorganicanions. The system was satisfactorily applied to thedetermination of common anions in red algae(Eucheuma cottonii) and carrageenan could be carriedout within 15 min. The relative standard deviations(RSDs) for the retention time, peak area and peakheight of eight common inorganic anions (0.3 mMeach of F - , Cl - , NO 2 - , Br - , NO 3 - , HPO 4 2- , SO 42-and I - )were between 0.0-0.2, 0.1-0.4 and 0.1-0.3%.References1. Anna. C.U, M. B´athorib, G. Blundenc, 2000,Determination of elements in algae by differentatomic spectroscopic methods, MicrochemicalJournal 67,.39-422. Saari-Nordhaus R., J.M. Anderson Jr. 1997,Recent advances in ion chromatographysuppressor improve anion separation anddetectionJ. Chromatogr. A 782, 75.3. Shinji S ,, Y. Ogura, A. Miyanaga, T. Sugimoto,2002 Ion chromatographic system with a novelswitching suppression device, Journal ofChromatography A, 956 53–584. Chen. Y, L. Jing, X. Li, Y. Zhu, 2006 Suppressedanion chromatography using mixed zwitter-ionicand carbonate eluents, Journal ofChromatography A, 1118, 3–115. Toshimitsu. O, A. Isozakib, H. Nagashima, 1998,Studies on elution conditions for thedetermination of anions by supressed ioninteractionchromatography using a graphitizedcarbon column, Journal of Chromatography A,800, 239–245409