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Avoiding Matrix Interferences in Ion Chromatography Using Solid Phase Extraction. Alltech Associates, Inc. Brandstraat 12, 9160 Lokeren Phone: 09 340 65 65 • Web Site: www.alltechweb.com. Types of Sample Matrix Interferences in Ion Chromatography.
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Avoiding Matrix Interferences in Ion Chromatography Using Solid Phase Extraction Alltech Associates, Inc. Brandstraat 12, 9160 Lokeren Phone: 09 340 65 65 • Web Site: www.alltechweb.com
Types of Sample Matrix Interferences in Ion Chromatography • Samples with components that will damage the column. • Samples that are too acidic for cation analysis. • Samples that are too basic for anion analysis. • Samples that contain high concentrations of interfering ions.
Problems with Common Sample Preparation Techniques • Dilution and Filtration are not suitable when: • • The analytes are present at trace levels. • • The analytes differ greatly in concentration. • • Interfering compounds and analytes are both soluble.
Solid Phase Extraction (SPE) Cartridges for Ion Chromatography • Stable from pH 2 to 13. • Low IC interference levels. • Requires only 2 - 3mL of samples.
The Alltech Maxi-Clean™ IC Cartridge Construction Polypropylene Housing Packing Material Female Luer Inlet Male Luer Outlet Polyethylene Frits
Types of Maxi-Clean™ IC SPE Cartridges: • Maxi-Clean™ IC-RP • Maxi-Clean™ IC-Ag • Maxi-Clean™ IC-Ba • Maxi-Clean™ IC-OH • Maxi-Clean™ IC-H • Maxi-Clean™ IC-Na • Maxi-Clean™ IC-Chelate
General Procedure for Using Maxi-Clean™ IC Cartridges • 1. Precondition the cartridge by passing 5-10mL of IC grade water (use 5mL of methanol followed by 5mL of Water for Maxi-Clean™ IC-RP). • 2. Load the sample at a rate of 1mL/min or less. (Adjust the sample size to use 50% or less of the device’s capacity). • 3. Discard the first 1mL eluate. • 4. Collect and analyze the remaining eluate.
Maxi-Clean™ IC-RP Product Specifications • Packing: Polystyrene • Particle Size: 300µm • Retains: Hydrophobic components by a reversed-phase mechanism • Applications: Removal of hydrophobic organic components
Maxi-Clean™ IC-RP Removes Organic Contaminants • Trace Anions in Aniline 5351 1. Chloride 2. Nitrate 3. Sulfate Column: Anion/S, 250 x 4.1mm Mobile Phase: 4mM KHP pH 4.5 Flowrate: 2.0mL/min Detector: Alltech Conductivity Original Sample After Cleanup with Maxi-Clean™ IC-RP
Sample Preparation by Precipitation • Maxi-CleanTM IC-Ba • • For removal of sulfate and phosphate prior to analysis • Resin-2-Ba+2 + M+2SO4-2 Resin-2-M+2 + Ba+2SO4-2 • Maxi-CleanTM IC-Ag • • For removal of halides prior to analysis • Resin--Ag+ + M+X- Resin--M+ + Ag+X- • M=Sample cations X= Cl-, Br-, I-
The Solubility of Barium and Silver Salts in Aqueous Solutions Compound Solubility (g/100mL) Temperature (°C) BaF2 0.12 25 BaCl2 37.5 26 Ba(NO2)2 67.5 20 Ba(NO3)2 8.7 20 BaHPO4 0.01 - 0.02 N/A Ba2SO4 2.2 x 10-4 25 AgF 182 15.5 AgI 2.8 x 10-7 25 AgCl 8.9 x 10-5 10 AgNO2 0.155 0 AgBr 3.7 x 10-4 100 AgNO3 122 0 Ag2SO4 0.57 100
Maxi-Clean™ IC-Ba Product Specifications • Packing: Strong cation exchanger in the Ba2+ form • Particle Size: 106µm • Capacity: 0.8/2.4 meq. • Retains: Sulfate by precipitation • Applications: Removal of sulfate before the analysis of other anions
Maxi-Clean™ IC-Ba Removes Sulfate 5348 • 1. Fluoride • 2. Chloride • 3. Nitrite • 4. Bromide • 5. Nitrate • 6. Phosphate • 7. Sulfate Anions in Battery Acid Column: Anion/R, 250 x 4.1mm Mobile Phase: 5mM p HBA, pH 8.5 Flow rate: 1.5mL/min. Detector: Alltech Conductivity Original Sample After Cleanup with Maxi-Clean™ IC-BA
Maxi-Clean™ IC-Ag Product Specifications • Packing:Strong cation exchanger in Ag+ form • Particle Size: 106µm • Capacity: 0.8/2.4 meq. • Retains:Halides by precipitation • Applications:Removal of halides before analysis of other anions
Maxi-Clean™ IC-Ag Removes Chloride 5347 1 • Column: 250 x 4.1mm • Packing: Anion/R • Mobile Phase: 5mM p HBA, pH 8.5 • Flow rate: 1.5mL/min. • Detector: Alltech Conductivity Nitrite in Brine 1. Chloride 2. Nitrite 2 Original Sample After Cleanup with Maxi-Clean™
Maxi-Clean™ Cartridges to Adjust Sample pH • Baseline disturbances and/or system peaks result when sample pH differs from eluant pH. • Strong anion exchange resin in the hydroxide form removes anions and neutralizes an acidic sample. • Cation exchange resin in the hydrogen form removes cations and neutralizes an alkaline sample.
Maxi-Clean™ IC-OH Product Specifications • Packing:Strong anion exchanger in OH- form • Particle Size:75µm • Capacity:0.6/1.8 meq • Retains:Anions • Applications:Adjusting sample pH before cation analysis
Maxi-Clean™ IC-OH Neutralizes Acid • Column: Cation/R, 100 x 43.1mm • Mobile Phase: 3.2mM nitric acid • Flowrate: 1.0mL/min • Detector: Alltech Conductivity 5352 Monovalent Cations in 1M Nitric Acid 1. Sodium 2. Potassium Original Sample After pH Neutralization with Maxi-Clean™ IC-OH
Maxi-Clean™ IC-H Product Specifications • Packing:Strong cation exchanger in H+ form • Particle Size:106µm • Capacity:0.8/2.4 meq. • Retains:Cations • Applications:Adjusting sample pH before anion analysis
Maxi-Clean™ IC-H Neutralizes Hydroxide 5349 Trace Anions In Caustic Solution • Column: Anion/R, 150 x 4.1mm • Mobile Phase: 5mM pHBA, pH 8.5 • Flowrate: 1.5mL/min. • Detector: Alltech Conductivity 1. Fluoride 2. Bicarbonate 3. Chloride 4. Nitrite 5. Bromide 6. Nitrate 7. Phosphate 8. Sulfate Original Sample After pH Neutralization with Maxi-Clean™ IC-H
Maxi-Clean™ IC-Na Product Specifications • Packing:Strong cation exchanger in Na+ form • Particle Size:106µm • Capacity:0.8/2.4 meq. • Retains:Cations (exchanges cations for sodium) • Applications:Removal of cations from sample without changing sample pH
Maxi-Clean™ IC-Na+ Isolates Iron (III) 5813 • Column: Alltech Universal Anion, 150 x 4.6mm • Mobile Phase: 2mM EDTA, disodium salt • Flowrate: 1.0mL/min. • Detector: UV at 330nm • *Problem with IC-H+--> the precipitation of H4EDTA Analysis of Iron (III) Procedures: 1. Precondition IC-Na+ cartridge with 5mL water. 2. Load the sample to preconcentrate iron (III) present. 3. Wash with 10mL water. 4. Elute the iron (III) with 5mL of 25mM EDTA, disodium salt. 5. Analyze the eluant for iron (III). 1. Iron (III)
Maxi-Clean™ IC-Chelate Product Specifications • Packing:Styrene-divinylbenzene copolymer containing iminodiacetate ion • Particle Size:225µm • Capacity:0.2/0.6 meq. • Retains:Polyvalent metal ions (exchanges cations for sodium) • Applications:Removal of polyvalent metal ions from sample
Benefits of Alltech Maxi-Clean™ IC Cartridges • Remove interfering components from the sample matrix. • Little or no loss of sample. • Easy, quick, and convenient. • Disposable.