If the analyser does operate with a cut-off then the detection limit shall be determined by
making at least 10 repeat measurements of a certified reference material (CRM). The CRM
concentration shall either be at 100% of calibration / certification range or at a value that is
three times the concentration where the analyser is believed to cut-off or three times the
expected detection limit, whichever the greatest. The detection limit shall be determined
using equation (C1). When the detection limit is reported it shall be specified whether it was
determined using zero gas or a CRM.