ABSTRACT
A rapid method based on ultrahigh-performance liquid chromatography-quadrupole/electrostatic field orbitrap high-resolution mass spectrometry (UPLC-HRMS) was developed for the screening and confirmation of 20 mycotoxins in grain products. The samples were extracted with acetonitrile containing 2% (v/v) formic acid, and the extracts were cleaned up on Captive EMR-Lipid columns. The analytes were separated on a Thermo Hypersil Gold C18 column (100 mm×2.1 mm, 1.9 µm), and analyzed by UPLC-HRMS. The retention time and accurate mass of the parent ion were used for fast screening in full scan mode, while the accurate masses of the fragment ions were used for confirmation in the two-stage threshold-triggered full mass scan mode. The results revealed that the 20 mycotoxins showed good linear relationships in their respective mass concentration ranges. The correlation coefficients were not less than 0.99, and the limits of quantitation (LOQs) ranged from 0.25 to 20 µg/kg. The recoveries of the 20 mycotoxins in the sample ranged from 72.9% to 117.8% with the relative standard deviations (RSDs) from 2.9% to 15.2% at three spiked levels (n=6). This method has the advantages of high sensitivity and reliability, and is thus suitable for the rapid screening and confirmation of 20 mycotoxins in grain products.
Subject(s)
Edible Grain/chemistry , Mycotoxins/analysis , Chromatography, High Pressure Liquid , Edible Grain/microbiology , Mass Spectrometry , Reproducibility of ResultsABSTRACT
A method for the simultaneous determination of the residues of 11 quinolones in hotpot ingredients by quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction and ultra performance liquid chromatography-tandem mass spectrometric method (UPLC-MS/MS) was established. The sample was extracted with acetonitrile (containing 5% formic acid) and followed by stratifying with a salting-out agent. Clean-up of the extracts was processed by C18 and PSA, a modified QuEChERS procedure. The analytes were then separated on a Poroshell 120 EC-C18 column, and finally detected by tandem mass spectrometry in positive ESI mode. The linearity of all the 11 quinolones in the range from 1.0 to 100.0 microg/kg had correlation coefficients greater than 0.998. The limits of detection (LOD) of the method were from 1.8 to 3.1 microg/kg and the limits of quantification (LOQ) were from 6.0 to 10.3 microg/kg. The average recoveries of the 11 quinolones were in the range from 70.1% to 100.3%, with relative standard deviations from 2.42% to 10.88%. The established method is sensitive and of good recoveries. It can be applied as a rapid and reliable method for the determination of the 11 quinolones in hotpot ingredients.
Subject(s)
Chromatography, High Pressure Liquid , Food Contamination/analysis , Quinolones/analysis , Solid Phase Extraction , Tandem Mass Spectrometry , Limit of DetectionABSTRACT
To reveal the function of nitric oxide (NO) that has been reported as an intracellular second messenger and a diffusible intercellular messenger, a novel ultrasound-assisted liquid-phase microextraction (ULPME) and high-performance liquid chromatographic method for the determination of NO produced in PC12 cells has been developed. 1,3,5,7-Tetramethyl-2,6-dicarbethoxy-8-(3',4'-diaminophenyl)-difluoroboradiaza-s-indacene (DAMBO-CO(2)Et) has been used for NO trapping to form corresponding triazole (DAMBO-CO(2)Et-T). The enrichment factor of DAMBO-CO(2)Et-T reached 150 in 2.5 min with the proposed ULPME method. NO produced in (200+/-5) PC12 cells has been determined directly with the detection limit (S/N=3) of 2.5 x 10(-13)mol/L (5a mol), which was the lowest in HPLC determination of NO reported yet. The proposed method was sensitive, selective, convenient and rapid, which has great prospect in the qualitative and quantitative determination of NO in minimal biological samples.
