The use of partial least squares (PLS) in quantitative FTIR: Determination of gas concentrations in smoke gases of burning textiles

Abstract

Fourier transform infrared spectroscopy can be used for on-line smoke gas analysis of burning textile materials for several gases simultaneously. The technique is sensitive enough for the determination of the concentrations of compounds like H,O, CO,, CO, NO, NO,, SO,, C,H,O, HCI, HBr, HCN and HF. Quantitative analysis is, however, sometimes difficult to perform due to spectral interferences of two or more components. Simple mathematical techniques based on the direct relation between concentration and peak height or peak area then becomes impossible since they cannot be completely assigned to one component. Spectral subtraction can then be used but the results are sometimes unsatisfactory. Alternative techniques, like Partial Least Squares (PLS), provide excellent possibilities to overcome the problems due to overlapping spectral features, without making use of spectral subtraction. Robust calibration curves, based on PLS, can be constructed and used for prediction of unknown concentrations of different compounds in smoke gases. The use of PLS as a tool to overcome the problem of interfering components is demonstrated by application to the overlapping spectral bands of H,OICO, and of H,O/NO. PLS calibration curves for other interfering components can be constructed in an analogous way.

The combustion behavior of epoxy‐based multifunctional electrolytes

“…[45][46] The FTIR analyser was calibrated beforehand using a single pure gas to N 2 standards with well-known concentration to quantify 15 The FTIR analysis technique used has been validated during the SAFIR project [45][46] which constituted the basis for fire gases analysis carried out following the guidelines of the standard ISO 19702. [47][48][49][50][51][52][53]…”

Characterization of polyvinyl chloride–based floor covering thermal decomposition parameters in a cone calorimeter

“…The Fourier transformed infrared (FTIR) analysis technique used has been validated during the Smoke Gas Analysis by Fourier Transform Infrared Spectroscopy (SAFIR) project 60,61 which constituted the basis for fire gases analysis carried out following the guidelines of the standard ISO 19702. [60][61][62][63][64][65][66][67][68] First, to proceed to this 'calibration' step, several spectra (each one corresponding to a gaseous standard concentration diluted in N 2 ) for each species cited above were collected using our FTIR spectrometer. To obtain mixtures with different standard concentrations in N 2 , we used a dilution bench composed of several thermal mass flowmeters with outputs connected to transport the obtained gas mixture up to the FTIR gas cell through heated lines (T = 180°C).…”

Simultaneous Determination of Amitriptyline Hydrochloride and Propranolol Hydrochloride in Commercial Formulation by Multitudinal UV and Multivariate FT-IR Spectroscopic Methods

“…Classical Least Squares (CLS) is a multivariate FT-IR spectroscopic technique which can be used in the quantification of analytes in IR spectra. [5][6][7][8][9][10][11][12] When studying complicated multiple spectra which include broad and overlapping bands, this technique is especially suitable. In comparison to other widely used quantitative techniques, spectroscopic methods have the benefit of being simple to use and relatively less expensive.…”