The technique has the advantage of allowing isotopic differences to be detected using a standard atmospheric atomiser and a conventional hollow cathode source. The measurements are sufficiently robust to tolerate a limited variability of sample composition, background absorption from matrix species, and some instrumental parameters such as source intensity. Different isotopes show different responses with varying magnetic field strength across the atomiser. This allows a distinction to be made between the isotopes even though only a single source of natural isotopic composition is used. Results illustrating this behaviour are given for Pb 206, Pb 207, Pb 208.