ASTM D3341 Test Method for Lead in Gasoline-Iodine Monochloride Method
10. Report
10.1 Report the result to the nearest 0.01 g Pb/US gal at 60°F, 0.01 g Pb/UK gal at 60°F, or 0.002 g Pb/L at 15°C, as appropriate.
11. Precision and Bias
11.1 Precision - The precision of the method as determined by statistical examination of interlaboratory test results is as follows:
11.1.1 Repeatability - The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty:
Litre: 0.00365 + 0.0073A2
where:
A2 = the average of the results in grams of lead per litre at 15.5°C.
US gallon: 0.0138 + 0.0073A
where:
A = the average of the results in grams of lead per US gallon at 60°F (15.5°C)
UK gallon: 0.0166 + 0.0073A1
where:
A1 = the average of the results in grams of lead per UK gallon at 60°F (15.5°C)
11.1.2 Reproducibility - The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following values only in one case in twenty:
Litre: 0.0135 + 0.027A2
where:
A2 = the average of the results in grams of lead per litre at 15.5°C.
UK gallon: 0.0613 + 0.027A1
A1 = the average of the results in grams of lead per UK gallon at 60°F (15.5°C)
US gallon: 0.0511 + 0.027A
where:
A = the average of the results in grams of lead per US gallon at 60°F (15.5°C)
NOTE 9 - The above precision was obtained in an ISO cooperative test program on samples covering a range from 1.0 to 3.3 g Pb/US gal. In a subsequent ASTM testing program the range was extended down to 0.1 g Pb/US gal with equal or better precision. Although no samples with lead concentrations, as high as the 5.0 g Pb/US gal specified in the Scope were tested, there is no obvious reason why the method should not be equally satisfactory at that concentration.
NOTE 10 - In the cooperative test program from which the above precision was obtained, dimethyl yellow was used as the indicator.
11.1.3 Bias - It is not practicable to specify the bias of this test method for measuring lead because the responsible subcommittee, after diligent search, was unable to attract volunteers for an interlaboratory study.
12. Keywords
12.1 gasoline; iodine monochloride; lead
