Reagent for Ion-Pair Chromatography

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  The low UV type ion-pair reagent has minimal UV absorption in the short wavelength region. In addition, it is easily dissolved in the mobile phase because it is the solution.

  Use quaternary alkyl ammonium salts for compounds with an acidic functional group and alkyl sulfonates for compounds with a basic functional group.

• Specification (Low UV Type)
  (ex. 0.5 mol/L Tetrabutylammonium Dihydrogenphosphate Solution)

  Appearance	Colorless clear liquid
  Absorbance	200 nm: max. 0.50　254 nm: max. 0.15 210 nm: max. 0.30　300 nm: max. 0.10 240 nm: max. 0.15　350 nm: max. 0.05
  Fluorescence Test	to pass test
  Content	0.45-0.55 mol/L

Comparison of Absorbance

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Comparison between General Ion-Pair Reagents and Low UV Type Ion-Pair Reagent in the Low-Wavelength Region

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  (Fig.1)
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  (Fig.2)

• Analysis Conditions

  Column：	Wakosil®-Ⅱ 3C18HG (4.6 φ × 50 mm)
  Eluent ：	(Fig.1)	KH2PO4 (819 mg) + NaH2PO4 (714 mg) + 0.5 M Tetra-n-butylammonium Phosphate Sol. (10 mL) in 1,000 mL H2O
  	(Fig.2)	KH2PO4 (819 mg) + NaH2PO4 (714 mg) + 0.5 M Tetra-n-butylammonium Phosphate Sol. (Low UV Type 10 mL) in 1,000 mL H2O
  Flow rate： Detector： Sample：	1.0 mL/min. at 40℃ UV 205 nm, 210 nm Potassium Bromaide in H2O

Reference: Column washing after using ion-pair reagent

When using quaternary alkyl ammonium salts

For use of the mobile phase spiked with quaternary alkyl ammonium salts such as tetrabutylammonium hydroxide, immediately flowing water for column cleaning after use may cause the liquid in the column to become alkaline and deteriorate the silica gel packing agent.

In this case, wash with 0.1% phosphoric acid solution and replace with distilled water for HPLC and the storage solvent in this order.

The passed volume of each solvent is about 10 times the column volume.

Use of alkyl sulfonate

For column washing after using the mobile phase spiked with alkyl sulfonate, it is effective to wash not only with distilled water for HPLC but also with a solution prepared by mixing an equal volume of organic solvents (e.g., methanol, acetonitrile).

Then, replace with distilled water for HPLC and storage solvent, but attention should be paid to an increase in the column pressure.

The passed volume of each solvent is about 15 to 20 times the column volume.