Breaking it Down – The Importance of Sample Digestion in Analytical Chemistry

Chemical analysis is undertaken to understand the composition of a sample, and is critical in a wide variety of industries, from food manufacturing to pharmaceuticals. A common method employed is known as the Kjeldahl method, which can quantitatively determine the level of nitrogen within organic samples.

However, a wide variety of systems (including Optical Emission Spectrometers and Mass Spectrometers) require samples be in a compatible format for analysis. Sample digestion is a critical step in the process of forming a homogenous solution.

Back to basics of Sample Preparation

The simple answer to what digestion is the decomposition of a solid sample to a liquid state, which can employ the use of a variety of reagents ranging from strong acids, alkalis, or enzymes. By raising the temperature of this solution to above boiling, the process of dissolution can be greatly sped up.

A huge variety of materials are routinely prepared for elemental analysis through acid digestion. Pharmaceuticals, cosmetics, food products, metals, and biological matter… just to name a few!

The primary benefit of sample digestion is that the resultant solution is representative of the original material, in a format processable by a variety of analytical instruments and eliminating complex matrix events. The main downside is that understanding of relevant dissolution chemistry is relatively poor, which can lead to poor sample dissolution efficiency.

Ultimately when it comes to sample digestion you want to maximise acceleration of the process and sample homogeneity, which will lead to an increase in operational throughput and cost-efficiency!

Automatic vs Semi-Automatic – Which is right for me?

At A1 Envirosciences we offer the VELP Scientifica range of digestors, the DK semi-automatic series and the DKL fully automated models. They both come in a variety of capacities, for increasing the number of processed samples simultaneously and for different sizes of test tubes.

The basic procedure and benefits, including rapid heating aluminium block and reduced energy consumption compared to microwave digestor units, are the same for both the DK and DKL models. The main difference, is that the DKL series can be pre-set with up to 54 programmes (30 pre-set, 24 customisable), allowing for operator-free digestion. It truly is a case of hitting ‘START’ and going to make a cuppa. That, or spending your time more efficiently within the lab with alternate analysis (operator’s choice!)


Until chemical analytical instrumentation develops to the point where solid samples can be immediately added, liquified and analysed, digestion will continue to play a necessary role in sample preparation. What’s important is that if sample digestion is required in your lab, that you invest in a quality and efficient system. That will leave you time to focus on your remaining lab work and critical tea brewing opportunities.

If you are interested in investing a high-quality semi/fully automatic digestor unit, ring us on 0845 873 8181 or get in touch with us by email!