THERMOGRAVIMETRY INFRARED-SPECTROSCOPY (TG-FTIR) COUPLED ANALYSIS

In recent years, coupled or hyphenated techniques have become popular, and have been successfully applied to the solution of many analytical problems. HPLC-MS, tandem MS-MS, GC-FTIR, TLC-FID, GC-MS, etc. are bu t a few of the familiar abbreviations used for these one step, ''doubl e analysis'' techniques. The coupling of thermogravimetric analysis (T GA) and Fourier transform infrared spectroscopy (FTIR) is a good pract ical example (TG-FTIR) of such an instrumental approach for solving sp ecific analytical problems. This hyphenated technique provides a quant itative assessment of the process via the TG curve (the thermogram), a nd an identification of the decomposition products from the IR spectra of the evolved gases. The gases are transferred from the TGA instrume nt by means of a heated transfer-line to avoid the possibility of cond ensation. With such a combination, the sample may be introduced into t he TGA instrument without any form of chemical or physical modificatio n. Applying the sequential FTIR analysis adds a new dimension to TGA b y adding specificity, which it otherwise lacks, to the measurement. An alternate way of of looking at the combination is to consider the TGA instrument as a sample handling or sample treatment front-end to the FTIR, where one can make full use of the interpretive and diagnostic c haracteristics of infrared spectral analysis. This review reports and summarizes various investigations carried out with TG-FTIR and include s the applications of the technique to many different fields. It will demonstrate clearly that the method is an important tool, not only for the characterization of polymers, but also for the study specific com pounds and materials in biological matrices.