Document byXzM7QoQRjL9X42B5kbVxLv6

/ Report to ` Monsanto Industrial Chemicals Trace Analysis of TCDD University of Nebraska Department of Chemistry Lincoln, Nebraska 68588 September 11, 1979 Submitted by: Director Midwest Center for Mass Spectrometry SUBJECT TO PROTECTIVE ORDER. Assistant Director Midwest Center for Mass Spectrometry G0CLC67 GC/HRMS Analysis A Kratos MS-5076 ultra high resolution mass spectrometer was used for this analysis. The mass spectrometer was interfaced to a Perkin Elmer Sigma II gas liquid chromatograph. Data acquisition was accomplished with a Nicolet Model 1170 signal averaging computer. A. Gas Chromatography The column was a 6 ` x 1/4" O.D. glass containing a Dow mixed phase packin Typical operating conditions were: Helium flow rate of 17 cc/min: injector 270 C; column temperature program: 1.5 min at 250 and then ramped at 1Q c/min to 300 C and held there until the dioxin has eluted. The GC/MS inter face was a simple glass lined stainless steel capillary (no separator) and wa held at an average temperature of 250 C, Typical retention time for 2,3,7,8 TCDD was 4.0 minutes (peak width at 10% height approximately 60 seconds), B. Mass Spectrometer Conditions The electron impact source was used at 70eV ionizing energy and an accelerating voltage of 8KV. The source was set at 260 C. The instrument was tuned to a resolving power of 10,000 (10% valley definition). Data were acquired by the standard ion switching feature. The initial run was made monitoring the 320,322 peaks for the 2,3,7,8-TCDD. Then the instrument was adjusted to look at the 286/288 ions for the trichlorodioxins during a second run (retention time 2.0 min). The time required to sample two ions of interest was .8 sec. (.4 sec, per peak). The sweep width was 300 parts-per-tril1ion (+96 millimass units with the various TCDD signals c the center of the scan). The data were integrated for about 75 sweeps over the retention time of TCDD. The amplifier bandwidth was set at 3K Hertz, SUBJECT TO PROTECTIVE ORDER. GO D1663 C. Calculation of Results For these analyses, a calibration curve was prepared using standard solutions of trichloro and tetrachlorodioxins supplied by Monsanto for this study. From the sample signal intensity, the concentration of dioxin could be determined from the calibration plot. The detection limit was calculated by taking 2.5 times the noise level at 322(288) as the minimum detectable signal. The data in the attached tables summarizes our results. \ COOlo^9 Table I Analysis of Cl^-dibenzodioxin by GLC High Resolution Mass Spectrometry * ID Conc.(ng/ml) 6AM BAM IBM Method Blank #2 #3 #4 #5 nd 5 .064 .35 2600 2700 2200 6100 1300 350 o "J Detection Limit (ng/ml) .3 .02 .09 40 140 80 450 20 28 '32c/: -- .61 .82 .96 .79 .86 .77 .72 .77 .77 Many samples showed previously eluting peaks which may be isomers other than 2,3,7,8-TCDD. $ / 2 t* k su J ^ Q r C `. is l i J. ; U r/a C o-r^t^-C-! 0 1 /J CT TO PROTECTIVE: m ivr^ 022310 00L670 Table II Analysis of Cl3-dibenzodioxin by GLC High Resolution Mass Spectroscopy ID Cone, (ng/ml) 1Detection Limit (ng/ml) i 320/322 CcOn #2 440 #3 2 1 0 0 #4 900 #5 130 8 35 14 2 A later eluting peak (possibly another isomer) #3 12000 200 #4 30000 400 .99 .96 .95 .94 .96 r AT SUBJECT TO PROTECTIVE ORDER. 02234i G O O 16 71