Pyro-GC/MS for Identification and Quantification of Plastic Additives in Deformulation

Chemical additives are critical components in a wide range of polymer products, due to their ability to enhance material properties, including flexibility, stability, color, and resistance to wear and tear. From the household and automotive industries to medical applications, the impact of these additives extends far beyond mere aesthetics. There are several categories of plastic additives, for instance pigments and dyestuffs, antioxidants and UV stabilizers, and functional agents including flame retardants, anti-static additives, surfactants, and plasticizers. They can be small, volatile and semi-volatile molecules, or large and less or non-volatile compounds ^[1]. In the field of deformulation analysis, the analysis of plastic additives associated to plastic polymers is importance and necessary, because they are critical components and analyzing the nature and quantity of them is key in ensuring product quality, safety and compliance.

Challenge of Plastic Additives Analysis

Despite its importance, the analysis of organic plastic additives poses a significant analytical challenge. This arises from the complexity of plastic materials, the number of potential additives, their broad concentration ranges, and the intricacy of extraction procedures. To date, many conventional methods for organic plastic additives analysis in polymer materials have been published. The majority of them use Soxhlet extraction, coupled with GC/MS analysis, however, it may not provide sufficient accuracy or sensitivity, thereby necessitating the use of more advanced tools.

Analysis of Plastic Additives by Pyrolysis-GC/MS

Pyrolysis gas chromatography-mass spectrometry (Pyro-GC/MS) is a powerful analytical technique that employs heat to break down complex organic materials into smaller, more manageable compounds. It has emerged as a valuable tool for the identification and quantification of plastic additives and has gained interest over the past several years in the field of deformulation.

Pyro-GC/MS for the Identification of Plastic Additives: In this context, flash pyrolysis has become the most common pyrolysis technique for the analysis of additives. With this method, a small sample of the plastic is heated, causing it to decompose. The resultant gases are then separated by the gas chromatography section of the instrument, based on their properties. The additives are subsequently identified by determining their pyrolysis degradation products using the mass spectrometer. At present, many UV-light stabilizers (such as Tinuvin® 144 (PubChem CID: 93348), Tinuvin® 622 (PubChem CID: 54328974), Tinuvin® 770 (PubChem CID: 164282) and Chimassorb® 944 (PubChem CID: 93418)), antioxidant (such as Irganox® 1010 (PubChem CID: 64819)), plasticizers and various families of flame retardants (such as Tris(2-chloroethyl)phosphate (TCEP) (PubChem CID: 8295), decabromodiphenylether (decaBDE), Diisobutyl phthalate (DIBP) (PubChem CID: 6782), Di-n-butyl phthalate (DBP) (PubChem CID: 3026)) have been identified and semi-quantified ^[1].

Fig.1. Graphical abstract of plastic additives analysis by using Pyro-GC/MS.

Pyro-GC/MS for the Quantitative Analysis of Plastic Additives: Similarly, Pyro-GC/MS, with an initial thermal desorption (TD) step, is beneficial for the quantitative analysis of plastic additives. Through the generation of a calibration curve, it is possible to accurately determine the concentration of the recognized additives, thus providing insight into their impact on the plastic's overall properties. This quantitative information can also be valuable for labs conducting quality control testing or regulatory compliance checks. At present, plasticizers especially phthalates (such as DIBP, DBP, (BBP), DEHP, di(n-octyl) phthalate (DNOP)(PubChem CID: 8346), di-isononyl phthalate (DINP) (PubChem CID: 590836), and di-isodecyl phthalate (DIDP) (PubChem CID: 33599)) and brominated flame retardants in polymers have been quantified ^[1].

Advantages of Pyro-GC/MS

The use of Pyro-GC/MS for the analysis of plastic additives provides numerous advantages over traditional analytical methods. First, Pyro-GC/MS does not require any tedious and time-consuming sample preparation. Furthermore, it provides superior sensitivity, allowing for the detection and quantification of additives at even low concentration levels. Moreover, Pyro-GC/MS presents a faster and more efficient analytical alternative, capable of providing detailed additive profiles in a matter of minutes. This can significantly enhance the efficiency of the testing process of plastic deformulation.

Meet Alfa Chemistry

At Alfa Chemistry, we provide professional identification and quantification of plastic additives in deformulation service utilizing state-of-the-art Pyro-GC/MS technique. Of course, if you only need plastic additives analysis services, we can provide you with it. Our team of skilled formulation scientists and researchers will offer detailed analyses of plastic additives of all kinds of polymer products, enabling you to make informed decisions and achieve superior formulation outcomes.

Reference

Akoueson F., et al. Identification and quantification of plastic additives using pyrolysis-GC/MS: A review[J]. Science of the Total Environment, 2021, 773: 145073.

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