Identification and preparation of debromination products of DBDPE photodegradation by HPLC-APPI-MS coupled to semi-preparative liquid chromatography.

Decabromodiphenyl ethane (DBDPE) is widely used as an additive flame retardant and has led to global pollution. Its has a large molecular mass and is prone to debromination and degradation under photothermal conditions, resulting in smaller homologous compounds. Due to the lack of standard substances for debromination products, the in-depth study of DBDPE environmental geochemical behavior through debromination conversion has been hindered. Therefore, based on DBDPE photodegradation experiment, this study first analyzed and identified the brominated products of DBDPE using high-performance liquid chromatography-atmospheric pressure photoionization-time of flight mass spectrometry (HPLC-APPI-TOF/MS). Four debromination products-nonabromodiphenyl ethane (nona-BDPE), octabromodiphenyl ethane (octa-BDPE), heptabromodiphenyl ethane (hepta-BDPE) and hexabromodiphenyl ethane (hexa-BDPE) are identified based on the characteristic ion peak of [M-Br+O]- in negative ion mode. Subsequently, using methanol as the mobile phase, four debromination products of DBDPE were separated and purified with a semi-preparative high-performance liquid chromatography (SP-HPLC) system equipped with an Agilent Zorbax Eclipse PAH column (4.6 mm × 250 mm, 5 µm). The first-time acquisition of hexa-BDPE (60.00 µg), octa-BDPE (19.40 µg), hepta-BDPE (31.20 µg) and octa-BDPE (isomer, 45.20 µg) with purity exceeding 90 % has been achieved. Among them, the purity of one hepta-BDPE monomer is as high as 98.91 %. This study indicates that based on photodegradation experiments, the combination of HPLC-APPI-TOF/MS and SP-HPLC techniques can rapidly identify and prepare DBDPE debrominated products. This approach meets the requirements for preliminary research on the pollution characteristics of DBDPE debrominated compounds and offers a feasible solution for the preparation of standard reference materials for emerging pollutants.