Polybrominated diphenyl ethers (PBDEs) — commonly used flame retardants — are under scrutiny, as a result of their global presence and rapid bioaccumulation. Recently, legislative and commercial groups have initiated programmes to reduce or eliminate specific PBDE congeners because of their potential health threat. 

GC–MS analysis of PBDEs presents a wide range of challenges. PBDEs are unstable at high temperatures and will rapidly degrade under inappropriate GC conditions. Resulting from their low vapour pressure and high boiling point, a temperature programmed splitless injection must be used to minimize sample contact with metal surfaces in the injector port. Retention time is a critical parameter and must be minimized to avoid degradation. As a result, a short column with a thin stationary phase is optimal. For this application, a 15 M × 0.25 mm i.d. × 0.1 μm film Elite-5ht column was used. 

High molecular-weight detection by GC–MS requires a non-traditional calibration technique. The ions of the standard calibration gas PFTBA (FC-43, Heptacosa) are limited to mass-calibration fragments up to 614 u. The mass range of the Clarus 500 MS is 2–1200 u. To achieve accurate mass calibration in the upper half of this mass range (600–1200 u), it is necessary to use an alternate mass-calibration standard with known ions above 600 u. This technique uses a GC injection of the Triazine calibration standard, which produces ions up to 1185 u. 

Along with GC optimization and high-mass calibration, the data-acquisition functions of the mass spectrometer must be optimized to achieve maximum sensitivity, while collecting sufficient scans across each peak. Different combinations of SIR and scan functions are used to achieve necessary sensitivity. 

As demonstrated here, the PerkinElmer Clarus 500 GC–MS provided excellent accuracy, precision and sensitivity in the analysis of PBDE congeners. Ten PBDE congeners were calibrated and optimized. Sensitivity, linearity and stability were checked. A linear calibration range of 10–1000 ppb (50–5000 ppb for Octa- and Deca-BDE) was chosen, as a result of industry requests. Within this range, the curve for Deca-BDE, one of the most challenging flame retardants, demonstrated a linearity of R

  = 0.994. The stability was verified and over 20 Deca-BDE injections had a percent standard deviation for the peak area of 9.6%, showing that the area is extremely reproducible. 

The successful use of this application will allow analysis of many PBDE congeners by GC–MS. Method optimization demonstrated run times of less than 10 min, allowing for high throughput. Combining a short run time with system stability and required sensitivity allows for a complete application solution for PBDE analysis. 

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This application note will demonstrate a GC–MS analysis of common polybrominated diphenyl ether (PBDE) congeners. An optimized method will allow the Clarus GC–MS to provide ample separation and high yields of all PBDE congeners. The extended mass range of the Clarus 500 MS and high-mass calibration will produce mass spectra with very high levels of accuracy.

Analysis of Polybrominated Diphenyl Ethers Using the Clarus 500 GC–MS

Polybrominated diphenyl ethers (PBDEs) are among the most important and widely used flame retardants. Recent legislation banned certain PBDE congeners.

  EU directive 2003/11/EC prohibits the use of Penta-BDE and Octa-BDE for the member states of the European community.

  Therefore, analysis of PBDEs have received increased interest as a result of their known toxicity.  

The most efficient trace analysis technique for BFRs proved to be high resolution GC–MS using an isotope dilution technique for quantification, especially suited for metabolism and accumulation studies in biological matrices. 

All measurements were performed on the DFS high resolution GC–MS coupled to a TRACE GC Ultra gas chromatograph with split/splitless injector. Samples were injected using the TriPlus autosampler.  

 Thermo TRACE TR-5MS, 15 m, 0.25 mm i.d., 0.1 μm film. 

 one quantification and one ratio  confirmation mass each, detailed MID set-up (see Table 1). 

 Wellington Laboratories (not containing Octa- and Nona-BDEs). 

Autotuning for the highest sensitivity was performed on PFK mass 480.9688. 

PFK is also used as an internal mass reference providing a specific lock and calibration mass for each MID window (see Table 2). In every single MID measurement cycle, the instrument automatically performs an electric mass calibration taking these two reference masses as calibration points. 

Table 2: MID set-up, MID lock mode (masses in brackets; optional second ratio mass for native PBDE).			

All congeners in the employed PBDE standard can be separated on the 15 m TRACE TR-5MS column (Figure 1) in the order of their bromination degree. The use of a short 15 m column with a thin film is recommended to analyse the thermolabile Deca-BDE. 

The limits of quantification (LOQs) for the far higher boiling PBDEs are similar to those achieved for dioxin and PCBs. The quantification shows excellent linearity from the lowest fg range up to the highest standards (Figure 2).			

Using the DFS high resolution GC–MS, polybrominated diphenyl ethers (PBDE) can be analysed with highest selectivity providing LOQs in the low femtogram range with the same analytical certainty as required in the analysis of dioxins and PCBs. For further information please visit 

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1. California Legislature Bill No. 302, Chaptered 11 August, 2003. 

2. European Parliament and Council Directive 2002/95/EC on the Restriction of Hazardeous Substances (RoHS). European Parliament and Council Directive 2002/96/EC on Waist Electrical and Electronic Equipment (WEEE). 

General

Polybrominated diphenyl ethers (PBDEs) are among the most important and widely used flame retardants. Recent legislation banned certain PBDE congeners.? EU directive 2003/11/EC prohibits the use of Penta-BDE and Octa-BDE for the member states of the European community.? Therefore, analysis of PBDEs have received increased interest as a result of their known toxicity.

The Application Notebook-07-01-2006

Analysis of Polybrominated Diphenyl Ethers Using the Clarus 500 GC–MS

Trace Analysis of Brominated Flame Retardants with High Resolution GC–MS