One-pot derivatization/extraction coupled with liquid chromatography-tandem mass spectrometry for furfurals determination.

Furfurals (5-hydroxymethylfurfural, furfural and 5-methyl furfural) have potential toxic effects to humans. This study developed a simple and rapid one-pot derivatization/extraction procedure for effective sample preparation of furfurals in complex samples prior to instrument analysis. The sample solution was incubated with 1-pyrenebutyric hydrazide (PBH) and hydroxyl-functionalized multi-walled carbon nanotubes (MWCNTs-OH) in a vial for 3 min. During this process, the furfurals were effectively derivatized by PBH and the furfural-PBH derivatives were selectively captured by MWCNTs-OH simultaneously. The detection selectivity and accuracy were greatly improved for the following liquid chromatography-tandem mass spectrometry analysis. Quantifying furfurals was validated over the 0.5-500 ng/mL concentration range with satisfactory linearities (R2 >0.99), accuracies (84.7%-119.0%) and precisions (<9.0%). The limits of quantification of 0.30, 0.36 and 0.20 ng/mL for 5-hydroxymethylfurfural, furfural and 5-methyl furfural, respectively, were achieved. Finally, the validated method was successfully applied to determine furfurals concentrations in various samples.

A fully green sample preparation method for synthetic antioxidants determination in edible oils based on natural feather fiber-supported liquid extraction.

The current study proposed a novel feather fiber-supported liquid extraction (FF-SLE) method for extracting analytes from oil samples. The natural feather fibers were used as the oil support material and directly loaded in the plastic tube of a disposable syringe to construct the low-cost extraction device (∼0.5 CNY). The edible oil without any pretreatment including dilution was added directly to the extraction device, followed by the addition of the green extraction solvent of ethanol. As an example, the proposed method was applied to extract nine synthetic antioxidants from edible oils. The optimized extraction conditions for processing 0.5 g of oil were obtained when the syringe dimension was 5 mL, the extraction solvent was 0.5 mL of ethanol, the amount of feather fibers was 200 mg of duck feather fibers and the static extraction time was 10 min. The applications to seven kinds of feathers and seven kinds of edible oils all indicated the excellent oil removal efficiencies (>98.0%). Combined with high-performance liquid chromatography-ultraviolet, a quantification method was validated with satisfied linearity (R2≥0.994), accuracy (95.8-114.6%) and precision (≤8.3%) with the limits of detection ranging from 50 to 100 ng/g. The proposed FF-SLE method was simple, effective, convenient, low-cost, green and environmental-friendly for the extraction of analytes from oil samples prior to instrument analysis.

Kapok fiber-supported liquid extraction for convenient oil samples preparations: A feasibility and proof-of-concept study.

In this study, a novel kapok fiber-supported liquid extraction (KF-SLE) method was developed for conveniently extracting analytes from oil samples. Natural kapok fiber without any pretreatment was directly used as an oil support medium. The extraction device was conveniently constructed by directly packing some kapok fibers into a syringe tube. Due to the fibrous property of the kapok fiber, no filter plate was needed. The cost of a KF-SLE device was as low as 0.5 CNY. The KF-SLE process was conveniently conducted using a simple three-step protocol: (1) the oil sample without any pretreatment including dilution was added directedly; (2) then, the oil-immiscible extractant was added; (3) after waiting a certain time for static extraction, the extractant was eluted out by pressing the kapok fibers with the syringe plunger. The extractant could be directly transferred for subsequent instrumental detection. For the feasibility and proof-of-concept study, the method was applied to quantify four synthetic flavor chemicals in edible oils. Satisfied quantification results were obtained with the correlation coefficient (R2) being greater than 0.996, the relative recoveries ranging from 92.90% to 107.53% and intra- and inter-day RSDs being less than 7.56%. All in all, for the first time, the SLE technique was expanded to process oil samples and the method has the characteristics of low cost, environmental friendliness, high sample processing throughput and ease of automation, offering a promising approach for edible oil sample preparations.

On-tissue pyrene-1-boronic acid labeling assisted MALDI imaging of catecholamines in porcine adrenal gland.

In this study, an on-tissue chemical labeling - matrix assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) method was developed for visualization of the distribution of three catecholamine (CA) compounds (dopamine, epinephrine and norepinephrine) in porcine adrenal gland. Commercially available pyrene-1-boronic acid (PBA) was employed as an effective in situ derivatizing reagent dissolved in acetonitrile containing 0.1% pyridine for the chemical labeling and the matrix coating. Without extra matrix coating, the tissue section was directly analyzed by MALDI-MS. The detection specificity and sensitivity were greatly improved with the on-tissue PBA labeling and successful imaging of the three CAs in porcine adrenal gland was achieved. Compared with previously reported methods for MALDI-MSI of the CAs, the analytical strategy proposed in the study provided a robust, easy-to-use and low-cost on-tissue chemical derivatization method that facilitated simultaneous molecular imaging of the three compounds.

In-syringe cotton fiber-supported liquid extraction coupled with gas chromatography-tandem mass spectrometry for the determination of free 3-mono-chloropropane-1,2-diol in edible oils.

In the current study, natural cotton fiber was served as the supporter of water, and the water acted as an extractant for liquid-phase microextraction of polar components in low-polar edible oils. An in-syringe extraction device was constructed to facilitate the extraction process by simply loading a certain amount of cotton fibers between the syringe needle and the plastic syringe tube. Then, the extraction process can be conveniently conducted by pull-push the syringe plunger. It can be regarded as a new type of dynamic liquid-phase microextraction method while operated more convent. For the feasibility study, the novel in-syringe cotton fiber-supported liquid extraction (CF-SLECF-SLE) pretreatment method was applied to extract free 3-mono-chloropropane-1,2-diol (3-MCPD) in edible oils. Specifically, the cotton fibers supported a certain amount of water by successfully pulling-pushing 1 mL of water and 1 mL of HEX in/out twice, respectively. Then, 2.0 mL of diluted oil sample (containing 0.4 g oil) was loaded in and out four times for extraction, during which process 3-MCPD was extracted into the supported water. The extracted 3-MCPD was desorbed with 1 mL of ethyl acetate (EA), derivatized with trimethyl silane imidazole (TMSI), and analyzed by gas chromatography-tandem mass spectrometry (GC-MS/MS). For three different spiked edible oils, the internal standard normalized matrix effect (IS-normalized ME) values were in ranges of 96.3-104.8% with RSD being 4.3%, benefiting the accurate quantitative analysis. The limit of quantification (LOQ) was calculated to be 2 ng/g, which met the regular determination requirement of 3-MCPD in edible oils. Satisfied linearity was obtained in 2-500 ng/g, with correlation coefficients (R2) being 0.998. The relative recoveries were in the ranges of 96.9-110.5%. The intra-/inter-day RSDs were less than 8.2% and 10.2%, respectively. The proposed method provides an efficient, simple, low-cost, and easy to automate strategy for determining free 3-MCPD in edible oils.