Selective determination of mono- and dihydroxylated analogs of polybrominated diphenyl ethers in marine sponges by liquid-chromatography tandem mass spectrometry.

A number of bioactive brominated secondary metabolites, including hydroxylated polybrominated diphenyl ethers, have been isolated from algae, sponges, and bacteria. In the present study, a screening method using liquid-chromatography tandem mass spectrometry was developed for the identification and selective determination of dihydroxy (diOH), hydroxy-methoxy (OH-MeO), and dimethoxy (diMeO) analogs of tetra- to hexa-BDEs in marine biota. In negative atmospheric pressure chemical ionization (APCI) mode, diOH and OH-MeO analogs provided intense [M-H](-) ions, whereas diMeO analogs provided characteristic [M-Br+O](-) and [M-CH(3)](-) ions. This enabled the diOH-, OH-MeO-, and diMeO-PBDEs to be distinguished using selected reaction monitoring transitions in the APCI source. Recoveries of 2'-OH-6-MeO-2,3',4,5'-tetra-BDE in spiked marine samples were 84 ± 5 %, with a limit of quantification at 9.1 ng mL(-1) (signal-to-noise ratio = 10). The developed method was used to analyze two sponge species collected from Palau, Micronesia; the concentration ratio of diOH-tetra-BDE:OH-MeO-tetra-BDE was 10:1 for the Lamellodysidea sp., whereas it was 1:30 for the Callyspongia sp.

Simultaneous determination by APCI-LC/MS/MS of hydroxylated and methoxylated polybrominated diphenyl ethers found in marine biota.

A method has been developed for the simultaneous analysis of hydroxylated and methoxylated analogs of tetrabromodiphenyl ethers (OH-tetraBDEs and MeO-tetraBDEs) and of hydroxylated and methoxylated analogs of tetrabromobiphenyl (diOH-tetraBB and diMeO-tetraBB) using high performance liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry (APCI-LC/MS/MS) in negative ion mode. Chromatographic separation was performed on a 150 mm ODS column with acetonitrile:water (9:1, v/v) in mobile phase. Multiple reaction monitoring (MRM) was performed using the precursor [M-H]- ion for hydroxylated analogs, and the [M-Br+O]- ion for tetraBDEs and tetraBB, and their methoxylated analogs. The method was validated using cod liver oil samples spiked with nine analytes (100 ng/g) for linearity (r2 > 0.998), recovery (75-95%), repeatability (8-36% RSD), and sensitivity (limits of quantification (LOQ), 0.1-0.25 ng/g lipid for phenolic analytes and 6-80 ng/g lipid for neutral brominated compounds). The APCI-LC/MS/MS was applied to analyze tiger shark and bull shark liver samples, where their concentrations were up to 8 ng/g (lipid weight) for OH-BDEs, whereas they were up to 540 ng/g (lipid weight) for MeO-BDEs. The results were consistent with values determined by electron ionization (EI)-GC/MS. The first detection of 2,2'-dihydroxy-3,3',5,5'-tetrabromobiphenyl (2,2'-diOH-BB80) by this method was in marine sponge from Micronesia. The advantage of the LC/MS/MS method over GC/MS is that it provides rapid and simultaneous determination of OH-BDEs, MeO-BDEs, and their related analogs with a single preparation step and without the involvement of chemical derivatives. Although the method provides the different LOQ ranges between hydroxylated and neutral brominated analogs, future work could apply the method to the full range of PBDE-like contaminants present in the environment and in biota tissues.