many sample loading options are available with biologic duoflow chromatography systems. single injections of samples may be made using the many injection loops （from 50 µl to 5 ml） available for the avr7-3 sample inject valve. dynaloop dynamic loops are available in 25 ml and 90 ml for large-volume sample loading or repetitive injections of smaller volumes. use either the econo gradient pump or the model ep-1 econo pump to load large sample volumes directly onto the column. the sv5-4 buffer-se-lect valve can automate sample loading and chromatography protocols.