| 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 |
|
|
|
|
|
