Pre-treatment of river sediment and soil samples for cosmogenic isotope analyses (¹⁰Be, ²⁶Al) includes purification steps to obtain pure quartz sands prior to dissolution and element separation by ion chromatography column chemistry. From sieved samples, minerals are separated by magnetic separation and/or heavy liquids, and silicate and oxide minerals are chemically separated from quartz by leaching with acids (HF, HCl, HNO₃) at elevated temperatures.