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CH3CCl3 Scale
New CH3CCl3 standards were prepared in 2001-2003 from new reagent material (99.8% purity). | |||||||
The 1996 scale was based on standards made from reagent now known to | |||||||
contain several impurities (approx 94% pure). The interim 2002 scale was based | |||||||
on these new standards, but was not well-defined at mixing ratios less than 40 ppt. | |||||||
The following table defines the 2003 scale. Two equations are used to convert the 1996 | |||||||
scale and the interim 2002 scale to the current 2003 scale. | |||||||
CH3CCl3 calibration standards | |||||||
updated: October 2003 | |||||||
year | prepared | assigned | residual | ||||
(ppt) | (ppt) | (ppt) | |||||
ALM-64608B | 2001 | 99.1 | 99.5 | 0.4 | |||
ALM-65990A | 2002 | 124.8 | 125.1 | 0.3 | |||
ALM-33800A | 2002 | 104.0 | 102.7 | -1.4 | |||
ALM-38422A | 2002 | 187.2 | 187.1 | -0.1 | |||
SX-3506 | 2002 | 76.7 | 76.6 | -0.1 | |||
SX-3518 | 2003 | 20.7 | 20.6 | 0.0 | |||
SX-3519 | 2003 | 40.8 | 40.5 | -0.2 | |||
SX-3522 | 2003 | 33.8 | 33.9 | 0.1 | |||
std dev | 0.58 | ||||||
Convert 2002 scale to 2003 scale | |||||||
Y = -2.0022e-4*X^2 + 1.0402*X - 2.68 | |||||||
where X = conc (ppt) from 2002 scale | |||||||
convert 1996 scale to 2003 scale | |||||||
Y = -1.6120e-4*X^2 + 0.9654*X + 0.2 | |||||||
where X = conc (ppt) from 1996 scale |
