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Details for article 1 of 7 found articles
| Title: |
Comparative study of the linearity and sensitivity of electron capture and flame photometric detectors using a pesticide standard |
| Author: |
Cochrane, W. P. Maybury, R. B. Greenhalgh, R. G. |
| Appeared in: |
Journal of environmental science and health. Part B, Pesticides, food contaminants, and agricultural wastes |
| Paging: | Volume 14 (1979) nr. 2 pages 197-212 |
| Year: |
1979 |
| Contents: |
A study was undertaken to compare and evaluate the different types of 63Ni and 3H electron capture (ECD) and flame photometric detectors (FPD) as part of the Canadian Check Sample Program on Pesticide Residue Analysis. Twenty-seven laboratories were supplied with chlorpyrifos standard solutions for the determination of linear range and minimum detectable amounts (MDA). Each laboratory selected its own operating conditions except for the FPD study. Results for the FPD were compared with standardized flame conditions designed to optimize the exponential factor in the S-mode. The MDA of the ECDs (pulsed and direct-current) ranged from 0.09 to 0.17 pg/sec for 63Ni and 3H sources respectively. The corresponding MDA for the linearized ECDs (pulse modulated or constant current) was 0.04 pg/sec and a linear range of 104 or greater with nitrogen as the carried gas. Use of argon/methane and a pulse width of 0.1 usec extended this range to 105 but the sensitivity was not as great as with nitrogen carrier gas. The practical limit of detector sensitivity was found to be instrument dependent depending primarily on the noise level. In the FPD study, operating in the P-mode gave an average MDA of 5.97 pg/sec and a linear range of 2 x 103. Similarly, the S-mode parameters were 81.1 pg/sec and 8 x 102 respectively with an average exponential factor of n 1.8. Attempts to apply optimized detector gas-flow conditions improved sensitivity and linearity in the S-mode only. |
| Publisher: |
Taylor & Francis |
| Source file: |
Elektronische Wetenschappelijke Tijdschriften |
Details for article 1 of 7 found articles
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