ATR-FTIR spectroscopy and quantitative multivariate analysis of paints and coating materials

• Quantitative analysis of paints and coatings by ATR-FTIR and PLS data analysis.
• Individual components in mixtures of binding media and pigments can be quantified.
• In most cases standard uncertainties of quantification are below 3 g/100 g.
• The method has the potential to quantify classes of components in alkyd resins.

The applicability of ATR-FTIR spectroscopy with partial least squares (PLS) data analysis was evaluated for quantifying the components of mixtures of paint binding media and pigments, and alkyd resins. PLS methods were created using a number of standard mixtures. Validation and measurement uncertainty estimation was carried out.Binary, ternary and quaternary mixtures of several common binding media and pigments were quantified, with standard measurement uncertainties in most cases below 3 g/100 g. Classes of components – aromatic anhydrides and alcohols – used in alkyd resin synthesis were also successfully quantified, with standard uncertainties in the range of 2–3 g/100 g. This is a more demanding application because in alkyd resins aromatic anhydrides and alcohols have reacted to form a polyester, and are not present in their original forms.Once a PLS method has been calibrated, analysis time and cost are significantly reduced from typical quantitative methods such as GC/MS. This is beneficial in the case of routine analysis where the components are known.

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