# Chemicals from Brominated Flame Retardants: Analytical Methods, Occurrence, Transport and Risks
## 2 Analytical Methods for the Detection of BFRs in Environmental and Biological Samples
### Dust Samples  
Dust samples are usually collected using commercial vacuum cleaners, and the nozzle of the vacuum cleaner is thoroughly cleaned with acetone before and after the collection of each sample to prevent cross-contamination [48]. Other methods of dust sampling may include: Surface Wipe Sampling using pre-cleaned wipes moistened with a suitable solvent (e.g., hexane) to wipe surfaces and collect dust particles; and Passive Dust Sampling, which involves the use of polyurethane foam (PUF) disks or polyethylene (PE) passive samplers in indoor environments to collect airborne dust over a specific period. Further methods involve Settled dust collection, Personal dust samplers, and Indoor dust traps in indoor ventilation systems or strategic locations to capture dust particles over time. The collected dust samples are sieved prior to extraction to remove extraneous matter and to obtain a homogenous sample of a particle size fraction that is more relevant to human exposure via dust ingestion or inhalation. Methods of dust extraction are similar to those of soil samples. The extraction of BFRs from dust samples can be achieved through several techniques, each offering distinct advantages and limitations in terms of extraction efficiency and recovery rates. The choice of extraction method should be guided by the specific requirements of the analysis, including the type of BFRs, the complexity of the dust matrix, and the available resources and equipment. SE, while reliable, is time-consumingand solvent-intensive. UAE is faster and uses less solvent but may have variable efficiency. PLE/ASE and MAE offer high efficiency and recovery rates with reduced solvent use, but both require specialized equipment. MAE is also a good extraction choice for thermolabile BFRs. SPE is highly selective and uses less solvent but involves careful optimization and involves multiple steps, which can complicate the extraction procedure. The SFE employs supercritical CO2, often with co-solvents, to extract BFRs The extraction method offers very high extraction efficiency, particularly for non-polar and moderately polar BFRs, and it is environmentally friendly but necessitates high-pressure equipment and high initial costs. [PERSON] et al. (2016) has reported the use of PLE for the extraction of HBCDDs and NBFRs in dust particles. In the study, the extraction was cleaned using two clean-up methods which included column clean-up (filled with activated aluminum oxide, deactivated silica, and some Na2 SO4 and eluted with hexanedichloromethane (1:1)) and Gel Permeation Chromatography, followed by quantification using GC-ECNI-MS and LC-MS-MS. While the limit of quantification (LOQ) was not reported, the result obtained showed a recovery of 68-116%. The study on the presence of PBDE and NBFR in indoor dust reported by [PERSON] et al. (2019) employed PUF for sampling and a combination of UAE and Soxllet extraction using acetone:hexane (1:1, _v.v._, 350 mL) for 24 h quantified by GCMS. The result also showed a recovery of (72.3-114)%. The BFRs in home dust and its contribution to brominated flame retardants' bioaccumulation in children's hair has been reported by [PERSON] et al. (2019). The researchers employed a novel microextraction approach to determine quantitative levels of selected OPEs and BFRs sampled from residential air filters from HVAC systems using a small volume of solvent. The microextraction method involved a series of steps that incorporated solvent extraction in hexane/acetone with ultrasonic extraction; the cleanup method was online to the GC/MS and LC/MS quantification. The results from the study showed a recovery range between 70 and 130%, and the LOQ values ranged between 0.010 and 0.020 ng/\(\mu\)L.