Ion chromatography of cations using indirect photometric of fluorometric detection

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:6712837

Sherman, J H

Copper(II) and cerium(III) were compared as mobile phase counter-ions with a strong cation exchange column for indirect photometric chromatography (IPC). Sample ion retention time was found to be dependent upon both counter-ion size and charge, as well as mobile phase ionic strength. Detection limits of all sample ions were found to be highly dependent on the molar absorptivity of the counter-ion at the wavelength of detection. At 254nm, a cerium(III) mobile phase provided detection limits at least 100 times lower than did a copper(II) mobile phase. The detection limit of sodium was about 4 ppb, corresponding to 3.5 pmoles, using a Ce(III) mobile phase. Cerium(III) was used as a mobile phase counter-ion with a strong cation exchange column using indirect fluorescence detection. Separation of the alkali metal ions along with the ammonium ion was achieved with baseline resolution. The detection limit of sodium was 3 ppb, corresponding to 2.6 pmoles. Separation and quantitation of sodium, ammonium, and potassium ions in diluted urine was straightforward. In contrast, using indirect UV detection, interference from the sample matrix was a problem. IPC using a cerium(III) mobile phase was used to determine sodium, potassium, magnesium, and calcium ions in milk and infant formulas. Separation was complete within 17 minutes. No interference from the sample matrix was noted. Good agreement between the IPC results and atomic absorption spectroscopy was found. Several complexes of chromium(III) were studied as mobile phase candidates for indirect photometric chromatography. A complex of tris(bipyridine)chromium(III) possessed the required spectral properties of an IPC counterion, but proved to be somewhat labile in either water or methanol but not acetonitrile.

• Research Organization: Miami Univ., Coral Gables, FL (USA)
• OSTI ID: 6712837
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102* -- Chemical & Spectral Procedures
ABSORPTION SPECTROSCOPY
ALKALI METALS
ALKALINE EARTH METALS
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
BODY FLUIDS
CALCIUM
CATIONS
CERIUM
CHARGED PARTICLES
CHEMICAL ANALYSIS
CHROMATOGRAPHY
CHROMIUM COMPLEXES
COMPLEXES
COPPER
ELEMENTS
FLUORESCENCE
FOOD
ION EXCHANGE CHROMATOGRAPHY
IONS
LUMINESCENCE
MAGNESIUM
MATERIALS
METALS
MILK
PERFORMANCE TESTING
PHOTOMETRY
POTASSIUM
RARE EARTHS
SEPARATION PROCESSES
SODIUM
SPECTROSCOPY
TESTING
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENTS
URINE
WASTES