INAA with anticoincidence counting significantly reduces interferences from the 554.3-keV photopeak of ⁸²Br to allow reliable measurements of nanogram levels of arsenic in solid biological materials via the 559.1-keV photopeak of ⁷⁶As

It is rather difficult to measure low levels of arsenic by instrumental neutron activation analysis (INAA) in biological materials containing high levels of bromine and antimony in particular, as well as sodium and potassium. The 559.1-keV photopeak of ⁷⁶As is interfered with by the 554.3- and 564.1-keV photopeaks of ⁸²Br and ¹²²Sb, respectively. The use of INAA in conjunction with anticoincidence spectrometry (INAA-AC) was found to reduce the background under the 559.1-keV photopeak by factors of 4–16 for the biological reference materials analyzed and to decrease the detection limit to 0.35 µg kg⁻¹ making the measurement of nanogram amounts arsenic in them possible.