Determination of cyclic and linear siloxanes in wastewater samples by ultrasound-assisted dispersive liquid-liquid microextraction followed by gas chromatography-mass spectrometry.
A fast, simple and environmentally friendly ultrasound-assisted dispersive liquid-liquid microextraction (USA-DLLME) procedure has been developed to preconcentrate eight cyclic and linear siloxanes from wastewater samples prior to quantification by gas chromatography-mass spectrometry (GC-MS). A two-stage multivariate optimization approach has been developed employing a Plackett-Burman design for screening and selecting the significant factors involved in the USA-DLLME procedure, which was later optimized by means of a circumscribed central composite design. The optimum conditions were: extractant solvent volume, 13 µL; solvent type, chlorobenzene; sample volume, 13 mL; centrifugation speed, 2300 rpm; centrifugation time, 5 min; and sonication time, 2 min. Under the optimized experimental conditions the method gave levels of repeatability with coefficients of variation between 10 and 24% (n=7). Limits of detection were between 0.002 and 1.4 µg L(-1). Calculated calibration curves gave high levels of linearity with correlation coefficient values between 0.991 and 0.9997. Finally, the proposed method was applied for the analysis of wastewater samples. Relative recovery values ranged between 71 and 116% showing that the matrix had a negligible effect upon extraction. To our knowledge, this is the first time that combines LLME and GC-MS for the analysis of methylsiloxanes in wastewater samples.
Labaqua S.A., C/Dracma 16-18, Pol. Ind. Las Atalayas, 03114 Alicante, Spain.
Carol
C
Cortada
Labaqua S.A., C/Dracma 16-18, Pol. Ind. Las Atalayas, 03114 Alicante, Spain.
Luciana Costa
LC
dos Reis
Departamento de Química Analítica, Nutrición y Bromatología e Instituto de Materiales, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain. Electronic address: lorena.vidal@ua.es.
Lorena
L
Vidal
Labaqua S.A., C/Dracma 16-18, Pol. Ind. Las Atalayas, 03114 Alicante, Spain.
Julio
J
Llorca
Departamento de Química Analítica, Nutrición y Bromatología e Instituto de Materiales, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain. Electronic address: a.canals@ua.es.
Antonio
A
Canals
D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000379:methods*; D012833:Siloxanes / Q000032:analysis*; D012997:Solvents; D013010:Sonication; D062065:Wastewater / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D012833:Siloxanes; D012997:Solvents; D062065:Wastewater; D014874:Water Pollutants, Chemical
Experimental design; Ultrasound-assisted dispersive liquid–liquid microextraction (USA-DLLME); Volatile siloxanes; Wastewater