Analysis of Multiple Markers in Nutrition Research

Abstract

A method is described to measure quantitatively by neutron activation analysis the rare earth elements lanthanum, europium, samarium, neodymium, terbium, ytterbium, lutetium, and elements chromium, cobalt, and scandium in digesta or fecal samples. Dried or ashed samples were placed in polyethylene vials, sealed, activated for 2 h at a neutron flux of 6 × 1012 neutrons cm−2s−1, and allowed to decay for 7 days (reducing interference from background matrix radiation, primarily sodium-24). Concentrations of each element then were determined simultaneously by induced gamma radiation measured with a lithium-doped germanium gamma ray detector. Detection of these elements is more sensitive with neutron activation analysis than by other analytical methods. Amounts required for quantitative measurement within a digesta or fecal matrix of 1 g (in micrograms) were: lanthanum .06, europium .02, samarium .004, neo-dymium .1, terbium .02, ytterbium .07, lutetium .04, chromium 1.2, cobalt .5, and scandium .004. Utilizing some or all of these elements as markers allows a large number of characteristics to be estimated simultaneously in the same animal. © 1985, American Dairy Science Association. All rights reserved.