Document XQdxwrN8kNLMoY35G7KnR7KB

AR226-2037 PECKSR 08/06/98 12:16 AM To: cc: Subject: SZAKATBK, MILLERSR , HALBERRM ESTILUO , 21PPEL, MILLERW, MAYLESM , air C8 recheck PARSONMA fts shown in the Table below, all air samples collected 7-29-98 appear to contain appreciable levels of C-8 except for the blank. These samples were analyzed with fresh reagent (from a new shipment that arrived late Wednesday). In addition to the "blank" Tenax tube, three additional blanks were examined. All blanks showed essentially clean baselines which verify the purity of the reagent. The GC response at retention time of "3.7 minutes (corr C8 pk) is shown to emphasize the levels of C8 observed. Table 1; C-8 in Air SAMPLE corr LOCATION A smoking area? 162 roof Liters C8 pk 18547 of air 50.7 ug C8 0.738 Bl blank tube 1309 44.2 0 Cl top of SW stairs, unit side 37058 52.3 1.545 01 SB rail 32870 45.6 1.363 E mid-rail, North 23812 48.2 0.968 mpb C8 0.82 0 1.66 1.67 1.13 Table 2t Calibration results corr Standard blank (0 ug) 0.1 ug standard 0.5 ug standard 1.0 ug standard C8 pk. 693 4090 14539 23797 Slope; 22948 intercept; 1600 R-2; 0.989 It should be stressed that although the electron capture detector (BCD) used in this GC method is extremely sensitive for fluorinated species (e.g. "C-8"), it is incapable of providing positive (qualitative) identification of analytes. It is theoretically possible that. the response (peak) interpreted as "c-8" is another substance ^ (or mixture) which co-elutes with C-8. ^ >--* K> Recommend additional samples be collected ASAP. Duplicates should be "^ obtained where possible as we are still working to improve robustness >-> EID937318 of this method and understand run-to-run variations. SP EID937319