Updated: January, 2008
Seven standards now comprise the GMD CCl4 scale. Four standards prepared in 1996 were
removed from the scale due to inconsistent performance.
The 2008 scale is 0.4% lower than the 1996 scale based on ECD results.
Standard Prepared Assigned Difference
(ppt) (ppt) (ppt)
SX-3519 49.8 49.02 -0.76
SX-3518 25.4 26.18 0.78
SX-3522 41.5 41.21 -0.29
SX-3506 94.3 94.91 0.64
SX-3505 47.3 46.97 -0.30
ALM-33800 127.71 127.93 0.22
ALM-65990 153.09 152.80 -0.29
std dev 0.57