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A solid phase extraction (SPE) high-performance liquid chromatography (HPLC) method was developed for the simultaneous determination of 10 phthalic acid esters (dimethyl phthalate, diethyl phthalate, dipropyl phthalate, benzylbutyl phthalate, diisobutyl phthalate, dicyclohexyl phthalate, diamyl phthalate, di-n-hexyl phthalate, di-n-octyl phthalate and di-2-ethylhexyl phthalate) released from food paper packaging materials. The use of distilled water, 3% acetic acid (w/v), 10% ethanol (v/v) and 95% ethanol (v/v) instead of the different types of food simulated the migration of 10 phthalic acid esters from food paper packaging materials; the phthalic acid esters in four food simulants were enriched and purified by a C18 SPE column and nitrogen blowing, and quantified by HPLC with a diode array detector. The chromatographic conditions and extraction conditions were optimized and all 10 of the phthalate acid esters had a maximum absorbance at 224 nm. The method showed limitations of detection in the range of 6.0–23.8 ng/mL the correlation coefficients were greater than 0.9999 in all cases, recovery values ranged between 71.27 and 106.97% at spiking levels of 30, 60 and 90 ng/mL and relative standard deviation values ranged from 0.86 to 8.00%. The method was considered to be simple, fast and reliable for a study on the migration of these 10 phthalic acid esters from food paper packaging materials into food. [ABSTRACT FROM AUTHOR]

A rapid method for the determination of five organophosphorus flame retardants (OPFRs) in textile wastewater was established by dispersive liquid-liquid microextraction (DLLME) based on solidification of floating organic drop (SFO) coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The analytes were extracted from the water samples by SFO-DLLME, which was performed using a mixture of an extraction solvent that was less dense than water, 1-undecanol, and a dispersive solvent, methanol. The influences of the SFO-DLLME parameters on the extraction efficiencies were studied. 1-Undecanol (extraction solvent, 400 μL) and methanol (dispersive solvent, 300 μL) were added to textile wastewater (containing 2 g NaCl) with pH between 6 and 9, and the solution was shaken for 2 min. Under optimum conditions, the linear ranges of the proposed method were from 2 μg/L to 100 μg/L with correlation coefficients ( R 2 ) above 0.99 for all the analytes. The limits of detection ( S/N =3) ranged from 2 μg/L to 5 μg/L. The precision of the method was evaluated in terms of repeatability; the relative standard deviations varied from 2.7% to 11.2% ( n =6). The relative recoveries ranged from 71.6% to 117.6% for all analytes. Only 3 of the 11 selected samples were tested positive for OPFRs, and the total concentrations of OPFRs in them were in the range of 2.6-3.4 μg/L. Hence, this method is accurate, environmentally friendly, fast, and convenient for the routine analysis of OPFRs in textile wastewater.

A comprehensive method for simultaneous identification and detection of 16 anabolic steroid hormones (ASs, including andorgens, gestagens and their esters) in muscle samples was developed with liquid chromatography coupled to quadrupole/linear ion trap mass spectrometry (LC-Q/Trap-MS). The ASs in muscle samples were extracted with acetonitrile under ultrasonic assistance. The extract was defatted by n-hexane with liquid-liquid partitioning and followed by clean-up with NH2 solid phase extraction (SPE) cartridge. The separation of analytes was carried out on a CAPCELL PAK C18 MG II column (150 mm x 2.0 mm, 5.0 microm) using mobile phases of 0.1% (v/v) formic acid in acetonitrile and 0.1% (v/v) formic acid-5 mmol/L ammonium formate aqueous solution with gradient elution. A scheduled multiple reaction monitoring (sMRM) in positive mode as survey scan and an enhanced product ion (EPI) scan as dependent scan in an information-dependent acquisition (IDA) experiment was adopted in mass spectrometry acquisition. On-line lab-built MS/MS library and internal standards were employed for the identification and quantification. As a result, the 16 ASs showed good linearity with all correlation coefficients (r) no less than 0. 999 0 within the linear ranges. The limits of quantification (LOQs, S/N > or = 10) for the 16 ASs were in the range of 0.029-0.36 microg/kg. At the three spiked levels (0.5, 2.0 and 20 microg/kg), the overall recoveries ranged from 89.9% to 118% with the relative standard deviations (RSDs) no more than 16.2% under within--laboratory reproducibility conditions. The proposed method can be used to identify and detect the 16 ASs in a single run, which makes it effective in residue surveillance of anabolic hormones in muscle samples.