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How to handle Surrogates in MassHunter Enviro GC or GCMS

Question asked by smeier on Apr 3, 2020
Latest reply on Apr 7, 2020 by smeier

We have been running MassHunter Data Analysis for several years doing volatiles THMs and EPA 624. In both of those methods the surrogate is always the same as it is added by the Purge and Trap. Now that we are bringing online extraction methods where you calibrate at one concentration and then back calculate to the concentration in the separatory funnel, the Outlier "Surrogate % Recovery" is not as useful as it is based on an added concentration and percent recovery limits that you choose. Thus, if I set it up for my separatory funnel determinations, then it flags all of my calibration standards.  I realize that for QC and Matrix Spike, I can enter limits into those separate outliers for those specific samples, but the issue still comes back to samples vs cal. The only solution I have found is to use a surrogate dilution column and set a dilution limit so that everything back calculates based on 20 ppb. 

In our setup the midpoint is 20 ppb as a calibration standard and a separatory funnel should be 100 times diluted (1000 mL to 10 mL when concentrated) so the separatory funnel is 200 ppt (or 0.2 ppb). When the sample is blown down it becomes 20 ppb in the volumetric flask though.  I am just curious is there a better way to set this up in MassHunter so that it doesn't flag every cal standard.  See the attached pdf for a visual explanation.