Modification of capillaries coupled to micro-flow nebulizers: a new strategy for on-line interference removal in inductively coupled plasma mass spectrometry.
The application of interference removal within modified silica capillaries for the introduction of liquid samples by a micro-flow nebulizer into an inductively coupled plasma quadrupole mass spectrometer is described using the example of (103)Rh and its mass interferences resulting from (63)Cu (ArCu(+)), (87)Rb (RbO(+)), (87)Sr (SrO(+)) and (206)Pb (Pb(2+)). A strong cation exchanger was covalently bound to the capillary surface and its ability to interact with cations in aqueous solution was investigated. At pH 7. 0 the interfering elements can be selectively adsorbed within the capillaries without hampering the elution of Rh. The capillaries are easily regenerated by flushing with 10(-3) M hydrochloric acid in order to exchange retained cations for protons. Calibrations show no significant difference between the absence and presence of interfering elements, so the detection limit for Rh of 6.0 ng l(-1) (3sigma) is not influenced by adding up to a 100-fold excess of interferents. The method developed is compared with a mathematical correction model for inductively coupled plasma mass spectrometry using the example of Rh determination in particulate car exhaust fumes and the results obtained are discussed.
Institut für Chemo- und Biosensorik, Münster, Germany.
H G
HG
Riepe
M
M
Gómez
C
C
Cámara
J
J
Bettmer
D002138:Calibration; D004785:Environmental Pollutants / Q000032:analysis; D013058:Mass Spectrometry / Q000379:methods; D012238:Rhodium / Q000032:analysis*
D004785:Environmental Pollutants; D012238:Rhodium