Application of simultaneous determination of inorganic ionic species by advanced ion chromatography

2012年4月色语Vol. 30 No. 4April 2012Chinese Journal of Chromatography365 ~ 368Meeting paper of the 5th Asia- Pacific Symposium on Ion AnalysisDOI: 10. 3724/SP. J.1123. 2011. 12050Application of simultaneous determination of inorganic ionicspecies by advanced ion chromatography for waterquality monitoring of river water and wastewaterNobutake NAKATANT', Daisuke KOZAKT , Kazuhiko TANAKA'(1. Department of Environmental and Symbiotic Science, College of Agricullure, Food andEnvironment Sciences. Rakuno Gakuen University, Hokkaido 069-8501 , Japan;2. Graduate School for Intermnational Development and Cooperation,Hiroshima Universily, Hiroshima 739 8529, Japan)Abetract: In this study, our recent work on advanced ion chromatographic methods for the simultaneousdetermination of inorganic ionie species such 8s common anions (SO: , Cl- and NO; ) and cations (Na* , NH: ,K*, Mg° , and Ca* ), nutrients ( phosphate and silicate) and hydrogen ion/ alkalinity are summarized first.Then, the applicatons using these methods for monitoring environmental water quality are also presented. Forthe determination of common anlons and cations with nutrients, the separation was successfully performed by apolymethacrylate-based weakly acidic cation-exchange column of TSKgel Super IC-A/C (Tosoh, 150 mm x6.0mm i.d.) and a mixture solution of 100 mmol/L ascorbic acid and 4 mmolL 18-crown-6 as acidic eluent withdual detection of conductivity and spectrophotometry. For the determination of hydrogen lonalkalinity, theseparation was conducted by TSKgel ODS-1002 column (Tosoh, 150 mm x4.5 mm i. d. ) nodifhed with lithiumdodecylsulfate and an eluent of 40 mmoVL LiCV0. 1 mmo/L lithium dodecylsulfate/0. 05 mmoVL H,SO, withconductivity detector. The differences of ion concentration between untreated and treated wastewater showedthe variation of iontc species during biological treatment process in a sewage treatment plant. Occurrence anddistrlbution of water-quality conditions were related to the bioavailability and human activity in watershed.From these results, our advanced ion chromatographic methods have contributed significantly for water qualitymonitoring of environmental waters.Key words: advanced ion chromatography; anions and cations; nutrlents; hydrogen ion/alkalinity; river warter; wastewater; water quality monitoringCLC number: 0658 Document code: A Article 1:1000-8713(2012>04-0365-04Determination of ionic species in water samplesachievedusingion-exclusion/ cation-exchangeprovides the useful information to evaluate andchromatography ( IEC/CEC ) with conductivitymanage the water quality. Since ion chromatogra-detector [2]. In this method, separation of ani-phy (IC) was developed as an effective tool forons by ion-exclusion mechanism and cations byseparation and detection of ionic species in natu-cation-exchange mechanism has been conductedral water and wastewater by Small et al. [1], itusing a single column packed with weakly acidichas been commonly applied for the water qualitycation-exchange resin and weakly acidic eluent.'monitoring. Recently, we have developed severalUsing the same column with ultra pure water oradvanced ion chromatographic methods. Simulta-diluted sulfuric acid as eluent, simultaneous spec-neous determination of anions ( sO?，Cl~,trophotometric determination of phosphate andNO;,I~, F~, HCOO" and CH,COO") and cat-silicateion-exclusion chromatographyions (Na*，NH', K*, Mg"* and Ca2*) was-(IEC) followed by postcolumn derivatization with中国煤化工●Corresponding author: Nobutake NAKATANI, Tel/Fax: +81|Y片C N M H G rakuno. ac.Jp.Foundation item: This work was supported by the Chugoku Regional Development Bureau of the Ministry ofLand, Infrastructure , Transport and Tourism, Japan.Received date: 2011-12-19，366●色第30卷molybdate was also conducted i3,4]. The IECcooling blocks. After filtration through a filtersystem for determination of phosphate and silicatepaper with 0.2 μm pore size, the water sampleswas simplified by using an ascorbate solution aswere stored in the dark room al 5 C until theeluent [ 5 ]. Furthermore, we have combinedanalysis. The Personal lon Analyzer ( PIA-1000 ,these methods to develop the simultaneous deter-Shimadzu) or Tosoh IC-2001 ion chromatographymination of common inorganic anionic speciessystem was used. The separation columns used inand cations in natural water and wastewater bythis study were a Tosoh TSKgel Super 1C-A/CIEC/CEC with dual detection of conductivity and(150 mmx6.0 mm i.d. ) at40 C for the simulta-spectrophotometry in tandem [6]. Hydrogen ionneous determination of common inorganic anionic(H* ) or alkalinity with monovalent cations werespecies and cations and a Tosoh TSKgel ODS-separated and detected using IC with conductivity100Z (150 mm x4.6 mm i.d.) at 40 C modified .detection by an OetadecylsilyI ( ODS ) -silica col-with lithium dodecylsulfate (Li-DS) for the deter-umn modified with lithium dodecylsulfate [7,8].mination of alkalinity. The modification of theInstead of conductivity detector， Ultra-Violetcolumn was achieved by passing 40 mmol/L Li-DS(UV) detector was used for simultaneous deter-solution through the column at a flow rate of 1.0mination of monovalent cations, hardness, andmL/min for 10 h.acidity/ alkalinity using unmodified silica gel col-umn and acidic copper sulfate solution as an elu-2Results and discussionent [9]. In addition, electrostatic IC [ 10] andTypical chromatograms for simultaneous determi-IEC/ anion- exchange chromatography [ 11] werenation of common anions and cations includingalso examined. These methods were individuallyphosphate and silicate in treated wastewater fromapplied to the determination of ionic species ina biological sewage treatment plant are shown inpractical water samples and demonstrated theFig.1. The separation of the common anions andusefulness of the methods.cations was performed using IEC/CEC by elutionIn this study， the water quality monitoring forwith 100 mmol/L ascorbic acid and 4 mmol/L 18-various environmental waters were examined withcrown-6 (pH 2.6) at 0. 6 mL/min, after whichan effective combination of advanced IC methods;the ions were detected by conductivity detector.simultaneous determination of common inorganicSubsequently，the postcolumn derivatization ofanionic species and cations [6 ] and determinationphosphate and silicate with the mixture solutionof alkalinity which was correlated with bicarbon-ate ion (HCO; ) [7]. We describe the validity of30I!our advanced ion chromatographic methods and10the useful information obtained from the analyti-20cal results.10;;1 ExperimentalRiver-water samples were collected from Gono-10[River in northern Hiroshima Prefecture in Novem-t1 minber 2008，and from Bibi River in Chitose City, .Fig. 1 Chromatograms of treated wastewater (2-timesHokkaido, Japan from May to August 2009. Indiluted) obtained from a biologieal sewageaddition, treated and untreated w astewater sam中国煤化工petor responses of conples were obtained from a biological sewage treat-dMYHCNMHGively.ment plant in Hiroshima Prefecture. The waterPeaks:1. sO;:2. UI ;3. NU, ;4. eluent dip for conduc-samples in polyethylene botles were transportedtivity detector;s. Na*;6. NH;;7. K';8. Mg*;9. Ca';10. phosphate; 11. silicate.to our laboratory in a cooling box with frozenNobutake NAKATANI, et al. : Application of simultancous determinationof inorganic ionic species by advanced ion chromatography for第4期water quality monitoring of river water and wastewater●367●of 50 mmol/L H,SO and 30 mmol/L sodiumconcentrations were almost the same，suggestingmolybdate occurred in a reaction coil, after whichthat the effect of biological treatment process tothe ionic species were detected by spectrophoto-reduce organic matter on the variation of thesemetric detector at 700 nm. The analytical per-ionic species is very few. On the other hand ,formance including linearity， detection limit ，NH+ concentration in treated wastewater was lessreproducibility and recovery was good [6_. In allthan a quarter of that in untreated water whileriver water samples，the concentration of NH:NO; concentration remains constant (Fig. 3). Inwas less than detection limit. Fig. 2 shows typi-the biological treatment plant， nitrification ofcal chromatogram for alkalinity with monovalentammonium ion and denitrification of NO; couldcations such as Na*， NH2* and K' in treatedoccur through the treatment process. Reducedw astewater. To maintain a constant amnount of Li-phosphate concentration in treated wastewaterDS on the stationary phasc of column, the eluentssuggests that phosphate is partially taken up withalways contain 0.1 mmol/L Li-DS. The separationactivated sludge and settled down during sedimen-of the common monovalent cations and alkalinitytation. From these results， our advanced ICwas performed by elution with 40 mmol/L LiCl/methods could be used for the management of a0. I mmolL Li-DS/0. 05 mmol/L H2SO,(pH 4. 0)sewage treating process.at 1.5 mL/min with conductivity detector with the20satisfactory analytical performance [ 7 ]. Themonovalent cations separated by the cation-曾15exchange mechanism were detected as positive10peaks, while the alkalinity was detected as a neg-ative peak in a vacant peak of acidity. There wasgood agreement in the analytical result of Na 'concentration in Gono River water samples (n =0UntreatedTreated10) between these two methods (y =0.97x，r=0.93)，while those of K* and NII* could not be2.0evaluated due to the low sensitivity of the lattermethod. This result suggests that the analyticalresults obtained by these two methods are compa-1.0rable.In untreated and trealcd wastewater of the sew-age treatment plant, Na', K', CI~ and silicate会0.050-1000.5 t-150中国煤化工售12141618YHC N M H GlreatedFig.2 Chromatogram of treated wastewater obtainedFig. 3 Concentrations of NI: . NO; and phosphatefrom a blological sewage treatment plantm in untreated and treated wastewaterPeaks: 1. Na ;2. NH:' ;3. K'; 4. alkalinity.obtnined from a biological sewage plant●368●色第30卷Distribution of ion concentrations from upstream3 Conclusionsto downstream of Gono and Bibi Rivers were vari-able. Concentrations of CI~ , SO:，Na*, Mg°*.Advanced IC methods， which were our recentCa'* and alkalinity were gradually increased fromwork, were successfully applied to monitor theupstream to downstream. However, the concen-water quality. These effective methods can betrations of nutrients such as NO; ，silicate andused for managing the w astewater treatmentphosphate in water of dam lake were much smal-process and for improving the environmental con-ler than those in upstream water of Gono River,ditions related to water quality.indicating that the nutrients flowing into the damAcknowledgementlake were used in biochemical process by phyto-We thank the staff members of Tosoh Corporationplankton. In Bibi River, the highest nitrate con-for their useful suggestions.centration was observed in headwaters (Fig. 4).There are many dairy and chicken farms aroundReferences:headwaters, suggesting that nitrate ion and relat-[1] Small H, Stevens TS, Bauman w C. Anal Chem, 1975, 47:ed nitrogen compounds derive from domestic ani-1801 .[2] Kozaki D, Goto R, Masuda W. et al. Bunseki Kagaku,mal wastes to Bibi River.2008, 57: 651[3] Nakatani N, Kozaki D, Masuda W. et al. Anal Chim Acla,口Ma;2008 , 619: 110[4: Nakatani N, Masuda W, Kooaki D. et al. Bunseki Kagaku,880 JulyIAu2009，58: 305Nakatuani N, Masuda W. Kozaki D, et al. Anal Sci, 2009 ,25: 3796° Nakatani N, KozakiD, Mori M, etal. Anal Scl, 2011, 27:49:7] Koraki D, Goto R, Nakatant N, et al. Bunscki Kagaku,2009, 58: 887°8] KozakiD, Goto R, Nakatani N, et al. Indst Wat. 2010.600: 71[9] Kozaki D, Goto R, Nakalani N. et al. Indst Wat. 2009，C。D597: 74Upsteam .Sampling siteDowteramn.L10] Masuda w. Kozaki D. Nakatani N, et al. 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