Composition of Extracts of the Elastomer
| pH | Concentration of Analytes (μg/g) | |||||
|---|---|---|---|---|---|---|
| Prepared | Measured | Ca | Zn | Stearate | Palmitate | Net TOC (1) |
| Low pH, 0.05 M sodium phosphate buffer | ||||||
| 2.5 | 2.6 | 28 | 450 | 1 | 2 | 370 |
| 3.0 | 3.1 | 14 | 320 | 1 | 2 | 320 |
| 3.5 | 3.6 | 7 | 510 | 1 | 2 | 330 |
| 4.0 | 4.1 | 6 | 340 | 1 | 2 | 350 |
| 4.5 | 4.7 | 8 | 290 | 1 | 2 | 320 |
| Intermediate pH, 0.05 M potassium phosphate buffer | ||||||
| 5.0 | 5.1 | 4 | 480 | 4 | 4 | 1630 |
| 5.5 | 5.6 | 2 | 350 | 4 | 5 | 1830 |
| 6.0 | 6.1 | 3 | 320 | 4 | 5 | 1670 |
| 6.5 | 6.6 | 4 | 250 | 4 | 6 | 1830 |
| 7.0 | 7.0 | 4 | 220 | 4 | 6 | 1940 |
| 7.5 | 7.5 | 4 | 150 | 7 | 12 | 1990 |
| High pH, 0.025 M borax (sodium tertaborate decihydrate) buffer | ||||||
| 8.0 | 8.0 | 27 | 15 | 5 | 51 | 790 |
| 8.5 | 8.5 | 43 | 23 | 24 | 160 | 850 |
| 9.0 | 9.0 | 36 | 59 | 72 | 450 | 5220 |
| 9.5 | 9.4 | 40 | 43 | 117 | 680 | 5850 |
| 10.0 | 9.9 | 59 | 58 | 152 | 920 | 2040 |
| 10.5 | 10.1 | 51 | 73 | 320 | 1550 | 7210 |
| 11.0 | 10.6 | 60 | 73 | 506 | 1890 | 7740 |
Note: (1) TOC = Total organic carbon. Extracted TOC = TOC in extract − TOC in extraction blank.