scholarly journals Optimization of a microwave-assisted extraction procedure for the determination of selected alkyl, aryl, and halogenated phenols in sewage sludge and biosolids

2016 ◽  
Vol 51 (4) ◽  
pp. 344-356 ◽  
Author(s):  
Hing-Biu Lee ◽  
M. Lewina Svoboda ◽  
Thomas E. Peart ◽  
Shirley Anne Smyth
Keyword(s):  
Sewage Sludge ◽  
Extraction Procedure ◽  
Negative Ion ◽  
Gas Chromatography Mass Spectrometry ◽  
Microwave Assisted Extraction ◽  
Alkyl Aryl ◽  
Microwave Assisted ◽  
Assisted Extraction ◽  
Halogenated Phenols

A microwave-assisted extraction method for the determination of 15 alkyl, aryl, and halogenated phenols in sewage sludge and biosolids samples was developed and optimized. The effects of solvent, temperature, time, moisture content, acid, and number of extractions on the recovery of phenols were evaluated. Results indicated that extraction solvent had the greatest impact on the recovery of all phenols while pH had the largest effect on recovery of hexachlorophene and pentachlorophenol. Wet sludge samples were extracted with acetone-hexane mixture in the presence of glacial acetic acid. The extract was evaporated, acetylated by acetic anhydride and cleaned up by silica gel. For dry sludge samples, an optional procedure for the simultaneous extraction and acetylation of phenols was also proposed. Triclosan (TCS) and the alkyl and aryl phenols in sludge extracts were analyzed by gas chromatography-mass spectrometry (GC-MS) in electron-impact mode while polyhalogenated phenols were analyzed by GC-MS in negative ion chemical ionization mode. Method detection limits were ca. 200 ng/g for nonylphenol, <25 ng/g for TCS and other alkyl and aryl phenols, and <5 ng/g for other halogenated phenols. This method has been applied to the determination of phenolic compounds in over 150 sludge and biosolids samples since 2009.

A Microwave-assisted Extraction Method for the Determination of Synthetic Musks in Sewage Sludge

2007 ◽  
Vol 42 (1) ◽  
pp. 11-19 ◽  
Author(s):  
M. Lewina Svoboda ◽  
Jian-Jun Yang ◽  
Patricia Falletta ◽  
Hing-Biu Lee
Keyword(s):  
Sewage Sludge ◽  
Negative Ion ◽  
Gas Chromatography Mass Spectrometry ◽  
Microwave Assisted Extraction ◽  
Microwave Assisted ◽  
Polycyclic Musks ◽  
Sample Extract ◽  
Nitro Musks ◽  
Assisted Extraction

Abstract An efficient microwave-assisted extraction (MAE) procedure has been optimized for the determination of polycyclic and nitro musks in sewage sludge. A centrifuged sludge cake sample (from 1 to 2.5 g ), mixed with 10 g of anhydrous sodium sulfate in a Teflon cell, was extracted with 30 mL of a 1:1 (v/v) mixture of acetone and hexane for 35 min, including a 15-min ramp with a 20-min hold at a controlled temperature of 110°C. After 30 min of cooling, the extract was evaporated and cleaned up on a silica gel column. A concentrated sample extract was then analyzed by gas chromatography/mass spectrometry (GC/MS) in the electron impact mode for the polycyclic musks and in negative ion chemical ionization mode for the nitro musks. This new method has been validated by comparing it to an established accelerated solvent extraction (ASE) method, with method detection limits ranging from 27 to 41 ng/g for the polycyclic musks, and approximately 4 ng/g for the nitro musks. Recoveries of most compounds in spiked samples ranged from 80 to 105%, although the MAE method produced lower recoveries for the nitro musks than the ASE method in archived sludge samples. The results generated by this MAE method were consistent with those prepared by previously reported techniques such as supercritical fluid extraction.

scholarly journals Determination of trans fatty acids in foodstuffs by gas chromatography-mass spectrometry after simultaneous microwave-assisted extraction-esterification

2010 ◽  
Vol 75 (6) ◽  
pp. 803-812 ◽  
Author(s):  
Snezana Kravic ◽  
Zvonimir Suturovic ◽  
Jaroslava Svarc-Gajic ◽  
Zorica Stojanovic ◽  
Mira Pucarevic
Keyword(s):  
Mass Spectrometry ◽  
Sample Preparation ◽  
Preparation Method ◽  
Reference Method ◽  
Gas Chromatography Mass Spectrometry ◽  
Microwave Assisted Extraction ◽  
Sample Preparation Method ◽  
Microwave Assisted ◽  
Assisted Extraction

A sample preparation method based on the simultaneous microwave-assisted extraction-esterification (SMAEE) was developed for the determination of the fatty acid composition of foodstuffs by gas chromatography-mass spectrometry. The proposed sample preparation method was validated by comparison with the reference Soxhlet extraction method followed by derivatisation by ester formation and the same determination step. The fatty acid compositions and the extraction efficiencies obtained using the proposed SMAEE method and the reference method were statistically similar. The results showed that compared to the conventional method, the SMAEE method offered the advantages of short sample preparation time, low consumption of expensive organic solvents and lower energy consumption. This good agreement between results provided by both the SMAEE and the reference method demonstrates the usefulness of the former as a routine method for the treatment of food samples prior to trans fatty analysis.

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