Identification of Composition and Origin of a White Plastic Fragment

HRL was approached by a client to investigate a foreign object found in a food item. The object was described as a small white plastic fragment. The client was concerned about the potential impact of foreign objects on their product quality and wanted to identify the source of the fragment. HRL was tasked with identifying the composition of the fragment and determining its origin.

HRL used a combination of analytical techniques to identify the composition of the fragment and determine its origin. The following methods were used:

1. Scanning Electron Microscopy with Energy Dispersive X-ray Analysis (SEM/EDX): SEM/EDX was used to analyse the surface morphology and elemental composition of the fragment. The technique allowed for the identification of the elements present in the fragment and their relative concentrations.

2. Fourier Transform Infrared Spectrometry (FTIR): FTIR was used to analyse the molecular composition of the sample. The FTIR spectra of the sample was compared with reference spectra of known materials to identify the composition of the fragment.

3. Semi-quantitative Sink-Float Density Test: The fragment's density was determined through a semi-quantitative sink-float density test. This test involved immersing the fragment in ethanol and water mixtures with known densities. The fragment's behaviour, whether it sank or floated, was observed to determine its relative density.

The FTIR spectrum of the fragment was compared with reference spectra of known materials and was found to be consistent with polyethylene. The SEM/EDX analysis confirmed the presence of carbon, which are the main components of PE. The density of the fragment was found to be consistent with High Density Polyethylene (HDPE).

Based on the results of the analysis, it was concluded that the fragment was a piece of HDPE plastic film. The client’s reference samples were analysed and compared, narrowing down the possible sources to one area of the packaging process.

In conclusion, the use of a combination of analytical techniques allowed HRL to identify the composition of the foreign object and determine its origin. The results of the analysis provided valuable information to the client and helped them improve their quality control procedures.