Nuclear magnetic resonance: its use to test fat content in food

This contract laboratory, with numerous sites throughout the UK and Ireland, provides quality control (QC) analytical services to the food industry. In converting from the wet chemistry method to an MQC benchtop nuclear magnetic resonance (NMR) analyser for measuring fat content, the laboratory has reaped significant economic and environmental benefits. Table 1 provides a brief overview of the advantages of NMR over secondary methods.

Wet chemistry resulted in bottlenecks
Customers send food samples to this contract QC laboratory, which offers a fast turnaround service. A typical request includes five or six measurements, including fat (oil) content. The Soxhlet method used for the oil measurement is slow, with results taking up to six hours. This situation led to serious bottlenecks that reduced throughput and affected the laboratory’s ability to deliver its promised rapid analysis service. The process is also rather cumbersome, can be inaccurate, and requires highly skilled personnel. In addition, many of the hazardous chemicals used are becoming increasingly unacceptable by international environmental standards.

Alternatives investigated
The laboratory began to seek a rapid technique that would improve turnaround time without increasing operating costs, and one that would also be comparable to the industry standard Soxhlet technique. There are a number of analytical methods that can be used to conduct the testing. They are often referred to as secondary techniques, as they are usually set-up to match the results produced by solvent extraction.