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Column: IonPac AS21, 2 mmEluent: 200 mM methylamineTemperature: 30 °CFlow Rate: 0.35 mL/minInj. Volume: 100 µLDiversion: Eluent divert valve before detector to send common anions

(e.g., chloride, bicarbonate, sulfate) to waste (openuntil 2 min prior to elution of perchlorate)

Detector: Triple quadrupole MS/MSPeaks: 1. Perchlorate 2.0 µg/L (ppb)

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The IonPac AS21 hydroxide-selective, anion-exchange column isdesigned for the fast separation ofperchlorate in drinking water,groundwater, and other matrices priorto detection with MS or MS/MS. TheAS21 2 × 250 mm column format wasspecifically developed for LC-MS orLC-MS/MS compatibility to allow useof volatile mobile phases such asmethylamine. Also, the AS21 can beused with Reagent-Free™ IonChromatography (RFIC™) eluentsin combination with suppressedconductivity detection prior to MSdetection. The IonPac AS21 is thespecified column in U.S. EPA Method331.0. The AS21 is ideal for theseparation of a variety of environ-mental anions including arsenate,tungstate, chromate, iodide,and perchlorate.

Superior ChromatographicPerformance

• Recommended anion-exchange

column for fast separation ofperchlorate prior to MS orMS/MS detection

• Optimized for methylamine or

hydroxide mobile phases

• Specified column for U.S. EPA

Method 331.0

• Optimum capacity: 45 µeq per

column (2 × 250 mm column)

• Operate at ambient or elevated

temperatures; column selectivityoptimized for a 30 °C operatingtemperature to ensure reproducibleretention times

• Compatible with HPLC organic

solvents that optimize the perfor-mance of the electrospray interface(ESI) to an MS or MS/MS detector,modify column selectivity, or thatallow effective column cleanup

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Figure 1. Structure of an IonPac AS21 packing particle.

Figure 2. Determination of perchlorate using the IonPac AS21 and MS/MS detection.

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Column: IonPac AS21, 2 mmEluent: 200 mM methylamineTemperature: 30 °CFlow Rate: 0.35 mL/minInj. Volume: 100 µLDiversion: Eluent divert valve before detector to send

common anions (e.g., chloride, bicarbonate, sulfate)to waste (open until 2 min prior to elution of perchlorate)

Detector: Finnigan LCQ Deca Ion Trap MS

Peaks: 1. Perchlorate 2.0 µg/L (ppb)

Conceptual illustration of surface modification

Parameter LC-MS/MSIon Source ElectrosprayPolarity NegativeSheath Gas (N2) 80Aux Gas (N2) 20Capillary Voltage –23 VCapillary Temp 275 °CSpray Voltage 6.00 KVTube Lens –35 VMultipole1 Offset 9.00 VLens Voltage 68 VMultipole2 Offset 12.50 VMultipole RF Amp 120Entrance Lens Voltage 44.00 VCoarse Trap dc Offset 10.17 VFine Trap dc Offset 10.15 VAnalyzer Temp 26 °CMultiplier Voltage –930 VMass Range LowInjection RF m/z 50Collision Energy 52%

High-Efficiency Particle StructureDionex has developed the IonPac

AS21 column using a new polymer-bonding technology. The stationaryphase consists of a novel hyper-branched anion exchange condensationpolymer, electrostatically attached tothe surface of a wide-pore polymericsubstrate. The substrate is surface-sulfonated in exactly the same manneras other Dionex latex-coated, anion-exchange packing materials. However,in this anion-exchange resin,alternating treatments of epoxymonomer and amines produce acoating that grows directly off thesurface of the substrate. Figure 1illustrates a model of the resinstructure. The resin capacity iscontrolled through the number ofalternating coating cycles. Theresulting polymer is extremelyhydrophilic and therefore has excellentselectivity for both methylamine andhydroxide eluents, allowing the useof lower eluent concentrations. TheIonPac AS21 column capacity(45 µeq/column) and selectivitywere optimized to determine traceperchlorate in drinking water matrices.

Determination of Trace Perchlorate inDrinking Water Using LC-MS/MS

Perchlorate (originally asammonium perchlorate), which iswidely used in the manufacture ofrocket propellants, has been found indrinking waters in areas whereaerospace materials and munitionshave been manufactured and tested.Perchlorate is a potential healthconcern because it interferes with theproduction of thyroid hormones. TheIonPac AS21 column was designedfor the fast analysis of low-levelperchlorate prior to MS or MS/MSdetection. The IonPac AS21 is thespecified column in U.S. EPA Method331.0 for the determination of traceperchlorate using LC-MS orLC-MS/MS. Figure 2 shows thedetermination of trace perchlorate in a

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Figure 3. IC/MS determination of perchlorate in drinking water using the IonPac AS21 column.

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(B) SIM m/z 107 35Cl18O4–ISTD*

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(B) SIM m/z 99 35Cl16O4–

Column: IonPac AG21, AS21, 2 mmEluent: 15 mM potassium hydroxideEluent Source: EGC II KOH cartridge with CR-ATCTemperature: 30 °CFlow Rate: 0.35 mL/minInj. Volume: 2.5 µLDetection: Suppressed conductivity,

ASRS ULTRA II, 2 mm,AutoSuppression® recycle mode

Peaks: 1. Fluoride 2 mg/L (ppm)2. Chloride 23. Nitrate 54. Carbonate –5. Sulfate 56. Tungstate 307. Chromate 308. Perchlorate 309. Phosphate 30

10. Arsenate 30

Figure 4. Analysis of environmental anions using the IonPac AS21 column.

Column: IonPac AG21, AS21, 2 mmEluent: 15 mM potassium hydroxideEluent Source: EGC II KOH with CR-ATCFlow Rate: 0.35 mL/minTemperature: 30 °CInj. Volume: 100 µLMatrix Diversion: 0–6.5 min.Auxiliary Pump Solvent: 50/50 acetonitrile/waterAuxiliary Pump Flow Rate: 0.3 mL/minDetection: (A) Suppressed conductivity,

ASRS MS, AutoSuppression,external water mode(B) Mass spectrometry

MS Instrument: MSQ™ PlusMS Conditions: –ESI, 70 V, 550 °CMatrix: Drinking WaterInternal Standard: Perchlorate-18O, 1 µg/L (ppb)Peaks: 1. Chloride –

2. Sulfate –3. Perchlorate 1

*ISTD = Internal Standard

drinking water sample using a 200 mMmethylamine mobile phase. Sub-µg/L(ppb) concentrations of perchlorate areeasily detected using MS/MS detection.Minimum reliable quantification levels ofperchlorate using the AS21 and LC-MS/MS are typically less than 50 ng/L (ppt).

Determination of Trace PerchlorateUsing IC-MS

The IonPac AS21 can also beused for the determination of traceperchlorate using IC-MS and IC-MS/MSwith a potassium hydroxide mobilephase. This method combines RFIC withmatrix diversion of common salts prior toMS detection. This method is verysensitive and selective when used for thedetermination of perchlorate isotopes(mass 99 and mass 101) as shown inFigure 3. Minimum reliable quantificationlimits for perchlorate using the AS21 inan IC separation mode with either MS orMS/MS detection are typically 50 ng/L(ppt) or less.

Determination of EnvironmentalAnions Using Suppressed ConductivityDetection

The AS21 column can be usedwith suppressed conductivity detectionfor the determination of environmentalanions, including the commoninorganic anions plus arsenate,tungstate, chromate, and perchlorate.Using an isocratic potassium hydroxideeluent generated by the eluent generator,these analytes can be separated inapproximately 16 min, as shown inFigure 4.

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SPEC IF ICAT IONS ORDER ING INFORMATION

��Printed on recycled and recyclable paper.

Dimensions:IonPac AS21 Analytical Column:

2 × 250 mm

IonPac AG21 Guard Column:2 × 50 mm

Maximum Operating Pressure:3000 psi

Mobile Phase Compatibility:pH 0–14; 0–100% HPLC solvents

Substrate Characteristics:Analytical Column:

Supermacroporous resinBead Diameter (µm): 7Pore Size: 2000 ÅCross-Linking (%DVB): 55%

Guard Column:Microporous resinBead Diameter (µm): 11Pore Size: <1 ÅCross-Linking (%DVB): 55%

Ion-Exchange Group:Functional Group: Alkanolquaternary ammonium ion

Functional Group Characteristics:Hydrophobicity: Ultralow

Capacity:45 µeq (2 × 250 mm column)1.5 µeq (2 × 50 mm column)

Column Construction:PEEK with 10-32 threadedferrule-style end fittings. Allcomponents are nonmetallic.

To order in the U.S., call 1-800-346-6390, or contact the DionexRegional Office nearest you. Outside the U.S., order through yourlocal Dionex office or distributor. Refer to the followingpart numbers.

Analytical and Guard Columns

IonPac AS21 Analytical Column (2 × 250 mm) .............. P/N 063009IonPac AG21 Guard Column (2 × 50 mm) ....................... P/N 063071

Dionex Corporation Dionex Corporation Dionex U.S. Regional Offices Dionex International Subsidiaries1228 Titan Way Salt Lake City Technical Center Sunnyvale, CA (408) 737-8522 Australia 61 (2) 9420 5233 Austria (01) 616 51 25 Belgium (03) 3-353 42 94 Canada (905) 844-9650 China (852) 2428 3282P.O. Box 3603 1515 West 2200 South, Suite A Westmont, IL (630) 789-3660 Denmark 36 36 90 90 France 01 39 30 01 10 Germany 06126-991-0 Italy (06) 66 51 50 52 Japan (06) 6885-1213 Korea 82 2 2653 2580Sunnyvale, CA Salt Lake City, UT Houston, TX (281) 847-5652 The Netherlands (0161) 43 43 03 Switzerland (062) 205 99 66 United Kingdom (01276) 69172294088-3603 84119-1484 Atlanta, GA (770) 432-8100 * Designed, developed, and manufactured under an NSAI registered ISO 9001 Quality System.(408) 737-0700 (801) 972-9292 Marlton, NJ (856) 596-06009

MSQ is a trademark of Thermo Electron Corporation.Reagent-Free and RFIC are trademarks, and AutoSuppression and

IonPac are registered trademarks of Dionex Corporation.

LPN 1674 7M 1/05©2005 Dionex Corporation