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1 <br /> SOP TO-14A/15 <br /> ' Rev 4 <br /> December 2007 <br /> ' Packard instruments should correctly integrate 90% or greater of the ion chromatograms correctly. It is <br /> recommended that the operator allow this to occur and to simply view or monitor the result. <br /> ' Sometimes manual integration is necessary. The following are some common examples in TO-15 where <br /> manual integration may be necessary. <br /> I. Gaseous VOCs at low levels <br /> Due to noise at the top of the peak the program may only choose one half of the peak <br /> to integrate. <br /> ' 2. Peak tailing <br /> Excessive peak tailing can add significant area to a peak. The peak should be cut off <br /> ' such that the peak is as symmetrical as possible. <br /> 3. Unresolved peaks <br /> ' The program may pick the wrong peak to quantitative. E.g.the internal standard <br /> chlorobenzene-d5 is not always completely resolved from chlorobenzene and the latter <br /> can be chosen. This may be manually integrated using a drop to baseline method. <br /> ' 4. Interference <br /> Interference with the target ion may require manual integration. E.g.the surrogate 1,4 <br /> ' bromofluorobenzene is often interfered by fuel hydrocarbons. <br /> 5. Noise in the baseline <br /> ' Noise in the baseline may add area to compounds which may incorrectly increase the <br /> amount detected. This is more often a problem at the lower levels. A noisy baseline <br /> can be witnessed by several small "bumps" in the ion chromatogram preceding or <br /> t following the peak of interest. If noise is evident it shall be acceptable to manually <br /> integrate from the top of the noise line instead of the "zero' baseline level. <br /> ' When manual integration is necessary, it must be documented. The operator should follow the <br /> following guidelines. <br /> ' Check to see how the particular compound integration is performed on the standards(ICAL,CCAL). <br /> Is it baseline, valley to valley, etc? <br /> Manually integrate the compound in the new data file in a manner as consistent with (a) as possible. <br /> ' Print copies of the computer integrated and manually integrated ion chromatogram showing the <br /> integration. <br /> ' Document the reason for the manual integration (see 1-4 above) sign and initial the hardcopies. <br /> ' 13.5 Qualitative Analysis <br /> ' Page 14 of 24 <br /> 1 <br />