Introduction
Supported Liquid Extraction (or Simplified Liquid Extraction) is very popular in the clinical research industry however the technique is gaining popularity in other industries as a faster, easier, and more reliable alternative to liquid-liquid extraction. This technical note will investigate an application with implications for the food safety industry using Novum SLE to clean up and extract acrylamide from both instant and brewed coffee.
According to the American Cancer society, cooking at high temperatures causes a chemical reaction between certain sugars and asparagine which causes acrylamide to form. Acrylamide is commonly found in foods that are made from plants such as potato products, grain products, and coffee whose preparation often requires longer cooking times and higher temperatures. In this technical note we explore how to use Novum SLE tubes to clean up a coffee matrix in order to quantitate known acrylamide levels, demonstrating that the SLE technique can be applied to a variety of compounds and sample matrices outside of the clinical research industry.
Experimental Conditions
Extraction Procedure
Sample Pre-treatment
Coffee was prepared the same way that it would normally be consumed. Prepared control coffee was left on the bench to reach room temperature before further pre-treatment.
- Ground Coffee Control (40 mg/mL)
- 60 g of ground coffee was percolated with 1500 mL of boiling water
- Instant Coffee Control (8 mg/mL)
- 2 g of instant coffee was dissolved in 250 mL of boiling water
Acrylamide standard was spiked into control coffee to reach 100 ng/mL (ground coffee) and 200 ng/mL (instant coffee) by adding 20 μL Acrylamide-13C3 (4 μg/mL in water) to 800 μL of the prepared coffee.
Sample Loading
- Add 150 μL 2 % Ammonium hydroxide in water to the spiked samples (from Pre-treatment step), vortex for 30 seconds.
- Load the sample onto the Novum SLE 6 cc tubes and apply a short and gentle pulse of vacuum (~5-10 seconds at 5” or less of Hg) until the sample has completely entered the media.
- Wait for 5-6 minutes.
Note: Inadequate or excessive wait periods can lead to variable recoveries and poor precision.
Elution
- Dispense 2x 2.5 mL of Ethyl acetate/Tetrahydrofuran (1:1) onto the Novum SLE sorbent and collect the solvent under gravity into a collection tube that contains 10 μL Ethylene glycol.
- Apply vacuum at 5” of Hg (or lower) for 20-30 seconds to complete the extraction.
Note: To reduce analyte loss due to dry down, ethylene glycol was added to the collection tube to prevent the sample from drying completely during the dry down step.
Dry Down
- Evaporate extracted samples to complete dryness under a slow stream of N2 at 45° C .
- Reconstitute sample in 300 μL of water.
>> Download the full Application Note as PDF
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