Sample storage and extraction efficiencies in determination of polycyclic and nitro musks in sewage sludge.
Analytical technology is continuously improving, developing better methods for isolating and concentrating trace compounds in environmental samples. Polycyclic and nitro musks (PNMs) are one group of emerging trace compounds detected in municipal wastewater. Differences in sample storage, preparation, and extraction methods for their measurement have led to variability in results. We analyzed 11 PNMs by GC/MS and compared the results of different storage times and extraction methods (supercritical fluid (SFE) or microwave-assisted (MAE)) for 202 samples of primary sludge, waste activated sludge (WAS), raw sludge, and aerobically/anaerobically digested biosolids collected from Canadian municipal wastewater treatment plants. Sixty-three air-dried samples were extracted by SFE, and 139 air-dried, centrifuged, or filtered samples were extracted by MAE. The mean surrogate recoveries were 89% (standard deviation (SD)=11%) for d(10)-anthracene by SFE and 88% (SD=14%) for d(10)-phenanthrene by MAE. Storage study results showed that PNM concentrations changed by a mean of 7% and 9% for primary sludge and WAS respectively after four weeks and decreased up to 25% after 13.5 months of storage in amber glass containers at -18 degrees C. Air-drying of sludge at room temperature caused losses of about 50% of PNM concentrations compared to centrifugation. The proportions of PNMs present in the liquid phase of sludge samples were less than 5% compared to proportions in the sludge solids. The most complete liquid-solid separation was achieved by filtration of frozen/thawed sludge samples, producing a liquid phase that contained less than 1% of the total musk content of the sample.
Smyth
Shirley Anne
SA
Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, P.O. Box 5050, Burlington, Ont., Canada L7R 4A6. Shirleyanne.Smyth@ec.gc.ca
Lishman
Lori
L
Alaee
Mehran
M
Kleywegt
Sonya
S
Svoboda
Lewina
L
Yang
Jian-Jun
JJ
Lee
Hing-Biu
HB
Seto
Peter
P
D002498:Centrifugation; D005591:Chemical Fractionation / Q000379:methods; D002623:Chemistry Techniques, Analytical / Q000379:methods; D005229:Fatty Acids, Monounsaturated / Q000032:analysis; D005615:Freezing; D007189:Indans / Q000032:analysis; D009574:Nitro Compounds / Q000032:analysis*; D009812:Odorants / Q000032:analysis*; D011083:Polycyclic Compounds / Q000032:analysis*; D012722:Sewage / Q000737:chemistry*
D005229:Fatty Acids, Monounsaturated; D007189:Indans; D009574:Nitro Compounds; D011083:Polycyclic Compounds; D012722:Sewage; C008563:musk