Feasibility of using beryllium as internal reference to reduce non-spectroscopic carbon species matrix effect in the inductively coupled plasma-mass spectrometry (ICP-MS) determination of boron in biological samples

The mechanism by which carbon matrix species cause non-spectroscopic matrix interference on boron (B) and beryllium (Be) during the determination of B in biological samples is investigated. The study indicates that, unlike ot her matrix species such as Ca and Na that cause non-spectroscopic matrix in terference only through space charge effect, carbon species manifest non-sp ectroscopic interference by two mechanisms. The minor non-spectroscopic int erference of carbon is through space charge effect. However, the major non- spectroscopic effect of carbon is by a charge transfer mechanism from C+-sp ecies to B and Be atoms in the central channel of the plasma discharge. The large difference in the magnitude of the carbon charge transfer non-spectr oscopic matrix interference between Be and B makes Be unsuitable as an inte rnal reference for B in solutions containing more than 1500 mu g/ml dissolv ed organic carbon (DOC). This DOC content is approximately half the DOC usu ally present in the final sample solution for B determination in biological samples. However, Be still acts as a perfect internal reference to B in so lution containing matrix elements that exert their non-spectroscopic interf erence effect through space charge mechanism (such as Na, K, Ca, etc.). (C) 1999 Elsevier Science B.V. All rights reserved.