2017 EPA Method Update Rule and EPA Method 624.1

Poster Presentation

Prepared by

Contact Information: [email protected]; 979-690-5226


Method 624 is for the determination of volatile organic compounds in industrial discharges and other liquid environmental samples by gas chromatography combined with mass spectrometry (GC/MS). The method was developed and validated through inter-laboratory studies more than 29 years ago. The purge and trap parameters were restricted to purging the sample at ambient temperature at 40ml/minute for 11 minutes and desorbing for 4 minutes. The method also required a closing CCV.

Method 624.1 will be a performance based method. New technology such as capillary columns, better purge and traps, optimized instrument parameters, and more sensitive GC/MS instruments will enable laboratories to achieve better %RSD’s than the prescribed 35% in Method 624 and 624.1. Allowing such high RSD’s on most compounds is often an indicator that the analytical system is out of control and associated data may be suspect. Internal Standards and Surrogate Standards can now be varied by compound and concentration to match 8260. Also since laboratories are permitted to use more stringent acceptance criteria than the method prescribes, it may be possible to analyze samples for Method 624.1 and 8260 at the same time. Method 624.1 requires running a matrix spike and matrix spike duplicate on 5% of every site or discharge sample set, which is a can be challenging when the work load is heavy. Method 624.1 also provides improvement in the procedure for Method Detection Limit (MDL) studies using 40 CFR Part 136 studies which many labs are already in the process of implementing

The purpose of this poster is to use method criteria from 624.1 and 8260 in a way that will most effectively and efficiently allow labs to run 624 and 8260 in the same batch.