DETERMINATION OF YTTERBIUM IN ANIMAL FECES BY TUNGSTEN COIL ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY

A method for ytterbium determination in animal faeces by tungsten coil electrothermal atomic absorption spectrometry (TCAAS) was developed. Faeces were dry-ashed in a muffle furnace, the ashes were treated with hydrochloric acid, and 10 mu l of sample solution were delivered into 150-W tungsten coil atomizer. A matrix-matching procedure employing a 66-s heating program proved to be efficient for obtaining accurate re sults. Characteristic mass and detection limit were 7.1 pg and 0.35 mu g g(-1) Yb, respectively. The tungsten coil atomizer lifetime exceede d 300 firings with digested solutions and R.S.D. of measurements was 1 .9% after ten consecutive injections of 10.0 mu g l(-1) Yb. Accuracy o f the proposed method was assessed by employing a graphite furnace ato mic absorption spectrometric procedure. Application of the paired t-te st did not reveal any significant difference for ytterbium contents de termined by both methods at 95% confidence level, it was demonstrated that the proposed procedure can successfully be used for evaluation of kinetic passage rate of feed through digestive tract of animals. (C) 1998 Elsevier Science B.V. All rights reserved.