The AOX/TOX sample preparation device has been designed by Analytik Jena. The APU system is extremely flexible and efficient, enabling the throughput of AOX samples to be increased. The APU system is an unparalleled two-channel system which doubles the speed or sample preparation and enables two samples to be prepared simultaneously, doubling the sample throughput. APU 28 provides individual sample and wash volumes and processes individual samples immediately in succession. APU 28 S can prepare two samples quickly and simultaneously and is a globally unparalleled two-channel system. APU 28 SPE provides fully automatic sample preparation including samples with a high saline content. The automatic filtration unit (AFU) provides semi-automated sample preparation of up to 3 samples simultaneously by batch method.