Development and validation of a multivariate calibration method for determining interfacial tension of transformers insulating oils by near infrared spectroscopy

作者：Godinho Mariana S; Oliveira Anselmo E; Sena Marcelo M^*

来源：Journal of Near Infrared Spectroscopy, 2011, 19(4): 243-251.

DOI：10.1255/jnirs.933

• NIR spectroscopy
• PLS
• power transformers
• insulating oil
• chemometrics
• net analyte signal
• NAS
• multivariate analytical validation

The aim of this study was to develop and validate a multivariate calibration method based on partial least squares (PLS) and near infrared spectroscopy for determining the interfacial tension of insulating oils used in electricity power transformers. Forty-eighty oil samples were obtained from an electricity power company and were divided into a calibration set of 38 leaving 10 for the validation set. The reference values were measured with a ring tensiometer and ranged from 15 dyn cm(-1) to 45 dyn cm(-1). The spectra were registered from 1280 nm to 2500 nm and the best PLS model was selected with 10 latent variables, providing a root mean square error of prediction of 2 dyn cm(-1) and a coefficient of determination between reference and predicted values of 0.962. This method was validated in the context of multivariate calibration and was considered to have adequate accuracy (prediction errors between -9% and 12%), precision and linearity. A bias test verified the absence of systematic errors in the model. A pseudo-univariate calibration curve was constructed based on the concept of net analyte signal. The proposed method was simple, rapid, non-destructive and considered appropriate for the routine use in a quality control laboratory of an electricity power company.

• 出版日期2011