Determination of Volatile Organic Compounds in PBAT Biodegradable Films by Headspace Solid-phase Microextraction Combined with GC¡ÁGC£­TOF MS

KeyWord:PBAT biodegradable films  headspace solid-phase microextraction  comprehensive two-dimensional gas chromatography£­time-of-flight mass spectrometry  volatile organic compounds

Abstract:

      A method suitable for qualitative and quantitative analysis was established to determine the main volatile organic compounds£¨VOCs£© in poly£¨butylene adipate terephthalate£©£¨PBAT£© biodegradable films by headspace-solid-phase microextraction£¨HS£­SPME£© combined with comprehensive two-dimensional gas chromatography£­time-of-flight mass spectrometry£¨GC ¡Á GC£­TOF MS£©. Effects of type of SPME fiber£¬ equilibrium temperature£¬ equilibrium time and extraction time on extraction efficiencies for VOCs in biodegradable films were investigated. The optimal SPME extraction conditions were as follows£º polydimethylsiloxane£­divinylbenzene£­carboxen£¨PDMS£­DVB£­CAR£© fiber was at 80 ¡æ extraction temperature for equilibrium time of 10 min and extraction time of 40 min. Then the fiber was introduced into the GC ¡Á GC£­TOF MS injector port and the extract was desorbed at 260 ¡æ for 3 min. The VOCs were identified using standard mass spectrum databases and structure spectra and quantified by internal standard method. Results indicated that 55 VOCs in the biodegradable film were identified. Compared with one-dimensional GC£­MS£¬ GC ¡Á GC£­TOF MS can effectively separate homologues£¬ isomers£¬ and interfering compounds£¬ and then obtain more accurate quantitative results. The identified compounds can be divided into 9 types according to the compound structure£¬ including£º benzenes£¬ naphthalenes£¬ aldehydes and ketones£¬ alcohols£¬ esters£¬ indenes£¬ amines£¬ phenols£¬ others£¬ etc. The intra-day and inter-day precision are both no more than 19% with good repeatability and reproducibility. The 55 VOCs in 4 kinds £¨A£¬B£¬C£¬D£© of PBAT biodegradable films from different manufacturers were analyzed with multivariate statistical analysis. The principal component analysis£¨PCA£© showed that PBAT A+B£¬ PBAT C and PBAT D are obviously different£¬ while PBAT A and PBAT B samples overlap. The PBAT biodegradable films from different manufacturers can be distinguished with VOCs composition£¬ and each biodegradable film has a characteristic difference£¬ The heatmap analysis shows the higher benzene homologues for PBAT D and naphthalene£¬ amines£¬ phenol for PBAT A+B£¬ while lower VOCs for PBAT C. The method of combining HS£­SPME and GC ¡Á GC£­TOF MS has accurate£¬ reliable£¬ simple£¬ rapid advantages and the VOCs results can provide reference value for the safety evaluation and use of PBAT biodegradable film.