Table 2: Results of retainability tests. Front, Back1, and Back2 were the front, 1st backup and 2nd backup tubes in series. Amounts of TMSOH in three tubes were expressed as the percentages of the initial amount spiked to the front tube.

Amount (ng)Vol (L)Flow Dual-bed tubesSingle-bed tubes
Front (%)Back1 (%)Back2 (%)Front (%)Back1 (%)Back2 (%)

101 N298.21.10.791.64.43.9
105 N296.00.73.366.628.74.8
1010 N299.40.40.278.720.80.5
1020 N297.81.01.268.527.14.5
2001 N299.50.50.194.35.70.0
2005 N298.90.30.824.634.041.4
20010 N297.81.11.218.435.046.7
20020 N299.50.40.123.038.538.5
20020Air99.70.3n.a.35.864.2n.a.
20020Air98.41.6n.a.40.959.1n.a.

Notes: aFlow matrix: the gas blown through tubes in retainability tests. n.a.: not available.