| Abstract |
The polybrominated diphenyl ethers (PBDEs) belong to the category of brominated flame retardants (BFRs). Their use has been increased through the last 30 years owing to the huge production of polymers and resins which must be flame-retarded, so that the total products in which these synthetic materials are used are as less flammable as possible. The specific flame retardants are used in buldings materials, textiles, carpets, sofas, mattresses, electrical appliances, televisions, computers, means of transportation, etc.
However, the retardants of this class are not chemically-combined to the materials. As a result, they can leach out of them over their entrire life, especially when they are exposed to high temperatures. Consequently, the continuous exposure of the environment in combination with their high persistence potential and the ability to accumulate, could determine their presence in the environment as well as in tissues for many years. Indeed, although their production and use were banned in 2004 in many countries of developed world, the amounts which are predicted to be released from the products that have been promoted in markets by now are huge, and they will be present for many years to come.
Although a large variety of studies has been published through the last 30 years for the determination of these retardants in different environmental matrices (such as airborne particles, sediments and sewage sludge), in mammals, in fishes, even in human body (blood, maternal milk, adipose tissue), the interest for their determination in urine and especially in human’ s urine is inexistent, probably due to their high lipophilic potential.
For that reason, the basic aim of the present study was the finding of a suitable method for the determination of these compounds in human’ s urine, in the case that they are excreted from the body in their initial form, namely as non-metabolized compounds. Basicly, the necessity of a large volume uptake of the samples and the application of the liquid-liquid extraction, were inevitable, because of the very low concentration levels expected in human’s urine (maybe below the low pgr/ml of urine).
However, the choice of the most suitable method for the specific analysis, was based on the most effective (according to quality parameters) method for the denaturation of the proteins hold these phenolic compounds. The method selected, included the addition of methanol in 10 ml urine, recoveries in the region of 83-96% and detection limits in the region of 0,190-1,651 pgr/ml urine for the congeners composed the recovery standard used.
Besides, the method developed, included the gas chromatography in combination with mass spectrometry, for the separation and the detection of these compounds, respectively. Moreover, the application of negative chemical ionization to the mass spectrometer was intentional, because our analytes (PBDEs) contain the very electronegative atoms of bromine. This technique has proved to provide better sensitivity to the specific analysis, although it is less «tough» from electron ionization.
Finally, the application of the selected method in human’s urine samples potentially exposed to these compounds, from people of defferent sex, age and occupation, proved that the detected amounts of non-metabolized PBDEs in these samples, and especially the amounts of the congeners BDE-47 and BDE-99, are similar to their levels in blank samples of the specific method. Specifically, the mean value of the amount of the the congener BDE-47 in the real samples was 9,4±3,1 pgr, while the same value in the blank samples was 9,0±3,6 pgr in 10 ml urine. Respectively, the mean value of the amount of the the congener BDE-99 in the real samples was 2,3±0,7 pgr, while the same value in the blank samples was 4,6±2,5 pgr.
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Προσδιορισμός βρωμιωμένων διφαινυλικών αιθέρων στα ούρα με τη μέθοδο αέριας χρωματογραφίας - φασματομετρίας μάζας με αρνητικό χημικό ιοντισμό
