Application Note: Solid phase extraction (SPE) in US EPA Method 625.1, the performance of smaller samples
15 May 2023
Environmental methods for water analysis often specify sampling 1 L of water to provide the sensitivity needed for determination
of contaminants at low concentrations for health monitoring. In the past decade sensitivity of the analytical technique (GC/MS)
has improved and with split/splitless introduction and large volume injection options a wide range of concentrations can be
effectively measured. Coupled with reduced concern about sample homogeneity and flexibility in sample size for automated
samplers, the possibility of smaller samples bears investigation. Other benefits of smaller samples include reduced shipping costs
and they are easier to handle and store than large bottles. Less solvent is needed for extraction and therefore less will be
evaporated when the sample extract is reduced. If solid phase extraction is used, rather than liquid-liquid, the solvent used may
be further reduced. In this application note, Biotage examines the results for a dramatically reduced sample size of 100 mL in EPA
Method 625.1. Several different matrices are examined,
including reagent water, synthetic wastewater, and an acetic acid mixture used in the toxicity characteristic leaching procedure.
Samples are spiked with a test mixture to determine recoveries of varying unknown concentrations.
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