A further model was generated for samples under positive ionisation without pH modification, over 80% of the sample set (n=40), with the remaining 20% (n=10) used to validate the model and provide reassurances against over-fitting. To ensure that all classes were represented in the model, splicing of the dataset was undertaken such that 20% of each class forms the 20% validation set chosen at random. The generated model correctly classified all 10 validation samples, indicating an absence of over-fitting while validating the model as a classification tool.