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In this study, the effects of fungal pretreatment and direct bio‐utilization of RSM for iturin A fermentation were comparatively analyzed through screening suitable fungal species, and evaluating the relationships between iturin A production and the composition of solid fermented RSM and liquid hydrolysates. Three main unconventional adverse effects were identified. In conclusion, our study verifies the unconventional adverse effects of fungal pretreatment on iturin A production by B. amyloliquefaciens CX‐20 compared with direct bio‐utilization of RSM., Summary Fungal pretreatment is the most common strategy for improving the conversion of rapeseed meal (RSM) into value‐added microbial products. It was demonstrated that Bacillus amyloliquefaciens CX‐20 could directly use RSM as the sole source of all nutrients except the carbon source for iturin A fermentation with high productivity. However, whether fungal pretreatment has an impact on iturin A production is still unknown. In this study, the effects of fungal pretreatment and direct bio‐utilization of RSM for iturin A fermentation were comparatively analysed through screening suitable fungal species, and evaluating the relationships between iturin A production and the composition of solid fermented RSM and liquid hydrolysates. Three main unconventional adverse effects were identified. (1) Solid‐state fermentation by fungi resulted in a decrease of the total nitrogen for B. amyloliquefaciens CX‐20 growth and metabolism, which caused nitrogen waste from RSM. (2) The released free ammonium nitrogen in liquid hydrolysates by fungal pretreatment led to the reduction of iturin A. (3) The insoluble precipitates of hydrolysates, which were mostly ignored and wasted in previous studies, were found to have beneficial effects on producing iturin A. In conclusion, our study verifies the unconventional adverse effects of fungal pretreatment on iturin A production by B. amyloliquefaciens CX‐20 compared with direct bio‐utilization of RSM.

We demonstrate a sensitive, easy and fast method for the fluorometric probing of the lipase level as acute pancreatitis biomarkers based on the novel interfacially controlled aggregation-induced emission (AIE) mechanism., As a sudden inflammation of the pancreas, acute pancreatitis presents severe complications and a high mortality rate, despite treatment. Lipase in serum serves as an essential biomarker of acute pancreatitis and even pancreatic cancer. Therefore, developing robust, convenient and sensitive probing of lipase levels is greatly needed. In this work, we present glutamate functionalized tetraphenylethylene (TPE) as a “turn-on” fluorescent probe (S1) based on the aggregation-induced emission (AIE) mechanism for lipase levels with new recognition units. In heterogeneous media, the hydrophilic amino and carboxyl groups in the probe were specifically introduced to facilitate its full access to lipase at the oil–water interface and achieve an interfacially controlled AIE process. The linear response of fluorescence ranging from 0 to 80 U L–1, which included the concentration range of the lipase level in human serum, considering the dilution factor if necessary, the limit of detection as low as 0.13 U L–1, and the fast response time (7 min) were determined. The value of the apparent Michaelis–Menten constant (K m) was obtained as 4.23 μM, which indicated superior affinity between lipase and the probe molecule. The selectivity, photostability, dynamic monitoring of the enzymatic reaction, and preliminary commercial enzyme activity screening were summarized. As far as we know, this is the fastest, easiest and most sensitive method for lipase level probing in the reported literature. Finally, probing the lipase level for the first time in real human serum samples was also conducted successfully.

The thermal stability of rapeseed oil fortified with 3 % sterol linolenate, sterol linoleate, and sterol oleate was investigated using the Rancimat accelerated oxidation method. The results indicated that the sterol ester content in fortified oil displayed positive correlations (P

A solid base catalyst Na2SiO3 was prepared by microwave heating. The catalyst was used to catalyze the transesterification reactions for the production of fatty acid methyl esters from cottonseed oil. The optimum conditions of the catalyst preparation and transesterification reactions were investigated by orthogonal experiments. The catalyst with the highest catalytic activity was obtained using microwave power of 640 W, microwave irradiation time of 6 min, catalyst particle size of 60 mesh. The catalyst was characterized with X-ray diffraction (XRD), scanning electron micrographs (SEM), and the results showed the catalyst Na2SiO3 has good microstructure. Under the transesterification conditions of methanol/oil molar ratio of 6:1, catalyst dosage of 5%, reaction temperature of 65 °C, reaction time of 100 min and stirring speed of 400 rpm, the yield of methyl esters was 97.6%. The lifetime of the solid base catalysts by different process methods (microwave heating and conventional electric heating) was no significant differences, but microwave heating may be more economical than conventional electric heating.

In this work, mixed-mode silica particles functionalized with octyl and sulfonic acid groups was conveniently prepared by co-bonding a mixture of n-octyltriethoxysilane and 3-mercaptopropyltriethoxysilane and then oxidized with hydrogen peroxide. Candida rugosa lipase (CRL) was immobilized on the mixed-mode silica particles via hydrophobic and strong cation-exchange interaction. The resulting immobilized CRL increased remarkably its stability at high temperature in comparison to free CRL. The immobilized CRL was used as biocatalysts for enzymatic esterification of phytosterols with free fatty acids (FFAs) to produce phytosterol esters. The phytosterols linolenate esterification degree of 95.3% was obtained under the optimized condition. Phytosterols esters could also been converted in high yields to the corresponding long-chain acyl esters via transesterification with methyl esters of fatty acids (80.5%) or triacylglycerols (above 95.5%) using mixed-mode silica particles immobilized CRL as biocatalyst. Furthermore, the immobilized CRL by absorption retained 78.6% of their initial activity after 7 recycles.

In this article, magnetic microspheres were prepared by suspension polymerization of allyl glycidyl and ethylene glycol dimethacrylate in the presence of vinylphosphonic acid-coated Fe3O4 nanoparticle. Candida rugosa lipase (CRL) was immobilized on the hydrophobic magnetic microspheres via the active epoxy groups. The resulting immobilized CRL had better resistance to pH and temperature inactivation in comparison to free CRL, the adaptive pH and temperature ranges of lipase were widened, and it exhibited good thermal stability and reusability. The immobilized CRL was used as biocatalyst for enzymatic esterification of phytosterols with unsaturated fatty acids (UFAs) to produce the corresponding phytosterol esters. The phytosterols linolenate esterification degree of 93.5% was obtained under the optimized condition: 100 μmol/mL phytosterols, 200 μmol/mL linolenic acid, 15 mg/mL immobilized CRL at 160 rpm and 55 °C for 15 h in 10 mL of isooctane. Phytosterols esters could also be converted in high yields to the corresponding long-chain acyl esters via transesterification with methyl esters of fatty acids (55.3%) or triacylglycerols (above 78.1%) using magnetic immobilized CRL as biocatalyst.

Magnetic solid base catalysts were prepared by loading Na2SiO3 on Fe3O4 nano-particles with Na2O·3SiO2 and NaOH as precipitator. The catalysts were used to catalyze the transesterification reactions for the production of fatty acid methyl esters (FAME, namely biodiesel) from cottonseed oil. The optimum conditions of the catalysts' preparation and transesterification reactions were investigated by orthogonal experiments. The catalyst with the highest catalytic activity was obtained when Si/Fe molar ratio of 2.5, aging time of 2 h, calcination temperature of 350 °C, calcination time of 2.5 h. Magnetic of the catalyst was characterized with Vibrating Sample Magnetometer (VSM) and transmission electron microscopy photograph (TEM), and the results showed the catalyst Na2SiO3/Fe3O4 had good specific saturation magnetization and paramagnetism, and its water resistance was better than the traditional homogeneous base catalysts; under the transesterification conditions of methanol/oil molar ratio of 7:1, catalyst dosage of 5%, reaction temperature of 60 °C, reaction time of 100 min and stirring speed of 400 rpm, yield of biodiesel was 99.6%. The lifetime and recovery rate of the magnetic solid base catalyst were much better than those of Na2SiO3.

In this study, direct esterification of phytosterols with polyunsaturated fatty acid (PUFA) catalyzed by sodium bisulfate to produce sterol esters of PUFA was performed without organic solvent. Considering on both degree of esterification (DE) and oxidative stability, response surface methodology (RSM) was employed for modeling the phytosterol esters of PUFA production to obtain a food grade process. The optimal and mild reaction conditions were obtained as follows: mass ratio of PUFA:phytosterols = 4:1; amount of catalyst: 3% of the raw materials weight; reaction temperature 130°C; reaction time 8 h. Under these conditions, the degree of esterification was up to 96%, GC, TLC, NMR and GC-MS results showed that purity of purified sterol ester was above 99%, and β-sitosterol linolenate account for about 88%. Sterol ester of PUFA possessed low peroxide value (PV) (0.96 meq/kg) and conjugated diene (CD) value (2.15 mmol/kg), and high oxidative induction period (OIP) (10.4 h). Addition amount of sterol ester of PUFA into soybean oil, rapeseed oil, and flaxseed oil below 1, 1, and 3%, respectively, could increase OIP of the vegetable oil. The primrose phytosterol esters of PUFA possessed very low melting point, crystallization temperature, and greater solubility in oils. All the characteristics favored the wide application of sterol ester of PUFA produced by the food grade process in different formulations of functional foods.

A rapid, sensitive and automated in-tube solid-phase microextraction-liquid chromatography-mass spectrometry (in-tube SPME/LC-MS) method was developed for the analysis of ten antidepressants in urine and plasma. A hybrid organic-inorganic silica monolith with cyanoethyl functional groups was prepared and used as a sorbent for in-tube SPME. Integration of the sample extraction, LC separation and MS detection into a single system permitted direct injection of the diluted urine or plasma after filtration. Under the optimized conditions, good extraction efficiencies for the targets were obtained with no matrix interference in the subsequent LC-MS. Automation of the sampling, extraction and separation procedures was realized under the control of a program in this study. The total process time was 30 min and only 30 μL of urine or plasma was required in one analysis cycle. Good linearities were obtained for ten antidepressants with the correlation coefficients (R) above 0.9933. The limits of detection (S/N=3) for ten antidepressants were found to be 0.06-2.84 ng/mL in urine and 0.07-2.95 ng/mL in plasma. The recoveries of antidepressants spiked in urine and plasma were from 75.2% to 113.0%, with relative standard deviations less than 16.5%. The developed method was successfully used to analyze urine sample from ageing patients undergoing therapy with antidepressants.

A method based on poly (methacrylic acid-co-ethylene glycol dimethacrylate) monolith microextraction and octadecylphosphonic acid-modified zirconia-coated CEC followed by field-enhanced sample injection preconcentration technique was proposed for sensitive CE-UV analysis of six antidepressants (doxepin, clozapine, imipramine, paroxetine, fluoxetine and chlorimipramine) in human plasma and urine. A poly(methacrylic acid-co-ethylene glycol dimethacrylate) monolithic capillary column was introduced for the extraction of antidepressants from urine and plasma samples. The hydrophobic main chains and acidic pendant groups of the monolithic column make it a superior material for extraction of basic analytes from aqueous matrix. After extraction, the desorption solvent, which normally provided an excellent medium to ensure direct compatibility for field-enhanced sample injection in CE, was analyzed by CE directly. By the use of alkylphosphonate-modified zirconia-coated CEC for separation of the basic compounds of antidepressants, high separation efficiency and resolution were achieved because that both hydrophobic interaction between analytes and alkylphosphonate-modified zirconia coat and electrophoretic effect work on the separation of antidepressants. The best separation was achieved using a buffer composed of 0.3 M ammonium acetate (adjusted to pH 4.5 with 1 M acetic acid) and 35% ACN v/v, with a temperature and voltage of 20 degrees C and 20 kV, respectively. By applying both preconcentration procedures, LODs of 11.4-51.5 and 3.7-17.0 microg/L were achieved for the six antidepressants in human plasma and urine, respectively. Excellent method of reproducibility was found over a linear range of 50-5000 microg/L in plasma and urine sample.

Problem Extensive studies have demonstrated that Th1 type immunity is predominant in pre-eclampsia, but there is little concern with regard to the intracellular mechanisms behind this initial T-cell polarization. In this study, we investigated whether the imbalance of the T-cell transcription factors contributes to it. Method of study A total of 15 pre-eclamptic patients and 15 healthy pregnant women were enrolled in this study. The expression levels of transcription factors for Th1 (T-bet), Th2 (GATA3), Th17 (RORc) and Treg (FOXP3) cells, together with the Th1/Th2 status, were simultaneously investigated in both peripheral blood mononuclear cells (PBMCs) and decidua. Results The expression levels of FOXP3 mRNA were decreased in both PBMCs and decidua from pre-eclamptic patients compared with healthy pregnant women (P

An analytical method based on online combination of polymer monolith microextraction (PMME) technique with hydrophilic interaction LC (HILIC)/MS is presented. The extraction was performed with a poly(methacrylic acid-co-ethylene glycol dimethacrylate) monolithic column while the subsequent separation was carried out on a Luna silica column by HILIC. After 1:1 v/v dilution with 20 mM phosphate solution at pH 7.0 and centrifugation, urine sample was directly used for extraction. After optimization, 85% ACN (containing 0.3% formic acid v/v) was used for rapid online elution, which was also the mobile phase in HILIC to avoid band broadening during separation or carry-over that was usually observed in PMME-RP LC system. Online automation of extraction and separation procedures was realized under the control of a program in this study. The developed method was applied to rapid and sensitive monitoring of three beta2-agonist traces in human urine. The LODs (S/N = 3) of the method were found to be 0.05-0.09 ng/mL of beta2-agonists in urine. The recoveries of three beta2-agonists spiked in five different urine samples ranged from 79.8 to 119.8%, with RSDs less than 18.0%.

A novel method of polymer monolith microextraction (PMME) using a poly(acrylamide-vinylpyridine-N,N′-methylene bisacrylamide) (AA-VP-Bis) monolithic column combined with electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) for the determination of trace Cd, Tl, and Pb with Pd as chemical modifier has been proposed. Several factors that influence the microextraction efficiency including pH value, sample flow rate, extraction time, sample volume, eluent volume, and coexisting ions, were investigated and the optimal microextraction conditions were established. The chemical modification of Pd in ETV-ICP-MS has been studied and the results indicated that the pyrolysis temperature for the target analytes could be increased up to 600 °C and the signal intensities were increased by 4.1, 2.1, and 13.8 times for Cd, Tl, and Pb, respectively. Under the optimized conditions, with a consumption of 0.4 mL sample, the limits of detection (LODs) were 1.1, 0.5, and 0.2 ng L−1 for Cd, Tl, and Pb, and the relative standard deviations (RSDs) were 10.3, 9.7, and 9.2% (C = 0.05 µg L−1, n = 5) for Cd, Tl, and Pb, respectively. The proposed method was successfully applied to the determination of trace Cd, Tl, and Pb in human serum and urine samples, and the recovery for the spiked samples were in the range of 90–110%. In order to validate the proposed method, certified reference material of GBW09103 human urine was analyzed, and the determined values were in good agreement with the certified values. The poly(AA-VP-Bis) monolith can be used more than 40 times without decrease in the extraction efficiency.

An octyl-functionalized hybrid silica monolithic column was developed for in-tube solid-phase microextraction (SPME) to perform on-line preconcentration coupled to capillary high-performance liquid chromatography (μHPLC) analysis. A hybrid silica monolithic column functionalized with octyl groups was conveniently synthesized by a two-step acid/base-catalyzed hydrolysis/co-condensation of tetraethoxysilane (TEOS) and n-octyltriethoxysilane (C8-TEOS). The size of through-pores as well as the carbon content can be adjusted by changing the ratio of TEOS to C8-TEOS in the polymerization mixture. The extraction characteristics of the monolithic column prepared under optimized fabrication conditions were studied by using polycyclic aromatic hydrocarbons (PAHs) as the analytes. The sample volume that could be injected into the system was increased up to 1 mL with simultaneous increase of column efficiency, when hybrid silica monolithic column was used as a precolumn. Good linear calibration curves (R > 0.999) were obtained, and the limits of detection (signal-to-noise ratio, S/N = 3) for the analytes were found to be between 2.4 and 8.1 ng/mL with a UV absorbance detector, which are 299–456 times lower than those obtained without preconcentration. The column-to-column RSD values were 1.3–8.0% for recoveries of PAHs investigated.

In this study, a novel mixed-mode composite material, SiO(2)@P(MAA-co-VBC-co-DVB), was prepared via the hyper-cross-linking of its precursor, which was produced via suspension polymerization in the presence of SiO(2) particles. Candida rugosa lipase (CRL) was immobilized on the SiO(2)@P(MAA-co-VBC-co-DVB) particles via hydrophobic and weak cation-exchange interaction. The resulting immobilized CRL showed much better thermal stability and reusability in comparison to free CRL. On the basis of the excellent biocatalyst prepared, a method for high-efficiency enzymatic esterification of phytosterols with different fatty acids to produce the corresponding phytosterol esters was developed. Six phytosterol esters with conversions above 92.1% and controllable fatty acid composition were obtained under the optimized conditions: 80 μmol/mL phytosterols, 160 μmol/mL linolenic acid, and 15 mg/mL CRL@HPCS at 300 rpm and 50 °C for 7 h in 30 mL of isooctane. The prepared phytosterol esters possessed a low acid value (≤0.86 mg of KOH/g), peroxide value (≤3.3 mequiv/kg), and conjugated diene value (≤1.74 mmol/kg) and high purity (≥97.8%) and fatty solubility (≥28.9 g/100 mL). All the characteristics favored the wide application of phytosterol esters with controllable fatty acid composition in different fields of functional food.

Water-compatible pefloxacin-imprinted monoliths synthesized in a water-containing system were used for the selective extraction of fluoroquinolones (FQs). The MIP monolith was synthesized by using methacrylic acid as the functional monomer, di(ethylene glycol) dimethacrylate as a cross-linker and methanol-water (10:3, v/v) as the porogenic solvent. The ability of the derivated MIP for selective recognition of FQs (ciprofloxacin, difloxacin, danofloxacin and enrofloxacin) and quinolones (flumequine, and oxolinic acid) was evaluated. The derivated monolith showed high selectivity and was able to distinguish between FQs and quinolones. A simple rapid and sensitive method using polymer monolith microextraction (PMME) based on the MIP monolith combined with HPLC with fluorescence detection was developed for the determination of four FQs from milk samples. Owing to the unique porous structure and flow-through channels in the network skeleton of the MIP monolith, phosphate buffer diluted milk samples were directly supplied to PMME; allowing non-specific bound proteins and other biological matrix to be washed out, and FQs to be selectively enriched. The limit of detection of the method was 0.4-1.6ng/mL and recovery was 92.4-98.2% with relative standard deviations less than 5.9%.

An organic–inorganic hybrid silica monolithic column with octyl and sulfonic acid groups has been prepared by sol–gel technique for capillary electrochromatograhpy. The structure of hybrid monolith was optimized by changing the composition of tetraethoxysilane (TEOS), octyltriethoxysilane (C8-TEOS) and 3-mercaptopropyltrimethoxysilane (MPTMS) in the mixture of precursors. Then, the obtained hybrid monolith was oxidized using hydrogen peroxide (30%, w/w) to yield sulfonic acid groups. The sulfonic acid group, which served as strong cation-exchanger, dominated the charge on the surface of the capillary column and generated stable electroosmotic flow (EOF) in a wide range of pH. The monolithic column was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and elemental analysis (EA), and the performance of column was evaluated in detail by separating different kinds of compounds with column efficiency up to 155,000 plates/m for thiourea. In addition, this monolithic column was also applied in the analysis of theophylline (TP) and caffeine (CA) in beverages. The detection limits were 0.39 and 0.48 μg/mL for theophylline and caffeine, respectively. The method reproducibility was tested by evaluating the intra- and inter-day precisions, and relative standard deviations of less than 3.9 and 8.4%, respectively, were obtained. Recoveries of compounds from spiked beverage samples ranged from 87.2 to 105.2%.

A hybrid organic-inorganic silica monolith with hydrophobic and strong cation-exchange functional groups was prepared and used as a sorbent for micro-solid phase extraction (micro-SPE). The hybrid silica monolith functionalized with octyl and thiol groups was conveniently synthesized by hydrolysis and polycondensation of a mixture of tetraethoxysilane (TEOS), n-octyltriethoxysilane (C8-TEOS) and 3-mercaptopropyltrimethoxysilane (MPTMS) via a two-step catalytic sol-gel process. Due to the favorable chemical reactivity of mercapto pendant moieties, the obtained hybrid monolith was oxidized using hydrogen peroxide (30%, w/w) to yield sulfonic acid groups, which provided strong cation-exchange sites. The obtained hybrid monolith was characterized by diffused infrared spectroscopy, elemental analysis, scanning electron microscopy and mercury intrusion porosimetry. The results show that the resulting monolith contains much higher carbon (31.6%) and sulfur (4.8%) contents than traditionally bonded silica materials. The extraction performance of the hybrid monolith was evaluated using sulfonamides as testing analytes by micro-SPE on-line coupled to HPLC. The results show that the hybrid monolith with hydrophobic and strong cation-exchange functional groups exhibits high extraction efficiency towards the testing analytes. The column-to-column RSD values were 1.3-9.8% for the extraction of SAs investigated. The extraction performance of the hybrid silica monolith remained practically unchanged after treated with acid (pH 1.0) and basic solutions (pH 10.5). Finally, the application of the hybrid monolith was demonstrated by micro-SPE of sulfonamide residues from milk followed by HPLC-UV analysis. The limits of detection (S/N=3) for eight SAs were found to be 1.0-3.0ng/mL in milk. The recoveries of eight SAs spiked in milk sample ranged from 80.2% to 115.6%, with relative standard deviations less than 11.8%.

A simple, rapid, and sensitive method is presented to determine seven trace quinolone antibacterials simultaneously in milk, egg, chicken and fish. This method is based on the combination of polymer monolith in-tube solid-phase microextraction with liquid chromatography and electrospray ionization quadrupole time-of-flight mass spectrometry (LC/ESI-QTOF-MS). LC/ESI-QTOF-MS offers the capability of unequivocal identification of target compounds from complex matrices, as well as the possibility of quantitation at low-level concentrations in real samples. The extraction was performed with a poly(methacrylic acid-ethylene glycol dimethacrylate) monolithic column. Under the optimized extraction conditions, good extraction efficiencies for the targets were obtained with no matrix interference in the subsequent LC/ESI-QTOF-MS. Good linearities were obtained for seven quinolones with the correlation coefficients (R) above 0.9951. The limits of detection (S/N = 3) for seven quinolones were found to be 0.3–1.2 ng/g in egg, 0.2–3.0 ng/mL in milk, 0.2–0.7 ng/g in chicken and 0.2–1.0 ng/g in fish. The recoveries of quinolones spiked in four different matrices ranged from 80.2 to 115.0%, with relative standard deviations less than 14.5%. The developed method was applied for the determination of quinolone residues in animal-producing food, and the positive samples were confirmed with high number of identification points (IPs) according to the IP system defined by the European Union (Commission Decision 2002/657/EC).

A method based on poly(methacrylic acid-co-ethylene glycol dimethacrylate) (MAA-EGDMA) monolith microextraction (PMME) and online preconcentration technique of field-amplified sample stacking (FASS) was proposed for sensitive capillary electrophoresis-ultraviolet (CE-UV) analysis of 12 sulfonamides (sulfamethazine, sulfamethoxypyridazine, sulfathiazole, sulfamerazine, sulfameter, sulfadoxine, sulfadimethoxine, sulfamonomethoxine sodium, sulfachlorpyridazine, sulfamethoxazole, sulfamethizole, and sulfisoxazole) in chicken samples. The conditions of PMME were optimized for the improvement of extraction efficiency and reduction of the matrix interferences from chicken sample. The best separation was achieved within 15 min using a buffer of 100 mM phosphate electrolyte (pH 7.3) with temperature and voltage of 20 degrees C and 25 kV, respectively. By applying FASS, detection limits of 3.49-16.7 ng/g were achieved with satisfactory precision (RSD

A simple, rapid, and sensitive method for the determination of traces of thirteen sulfonamide antibacterials in milk and eggs is presented. This method is based on the combination of polymer monolith microextraction (PMME) technique with hydrophilic interaction chromatography/mass spectrometry (HILIC/MS). The extraction was performed with a poly(methacrylic acid-ethylene glycol dimethacrylate) monolithic capillary column while the subsequent separation was carried out on a Luna NH 2 column by HILIC. To obtain optimum results, several parameters relating to HILIC and PMME were investigated. After optimization, acetonitrile (contain 0.05% formic acid, v/v) was used as the elution solution, which was well compatible with the mobile phase in HILIC. Good linearities were obtained for thirteen SAs with the correlation coefficients ( R 2 ) above 0.997. The limits of detection (S/N = 3) of the method were found to be 0.4–5.7 ng mL −1 of SAs in whole milk and 0.9–9.8 ng g −1 of SAs in eggs. The recoveries of thirteen SAs in two matrices ranged from 80.4 to 119.8%, with relative standard deviations less than 11.8%.

A novel method based on combination of a solid-phase extraction (SPE) with humic acid-bonded silica (HAS) as sorbent with electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QTOF MS) was developed for rapid and sensitive determination of four Sudan dyes in hot chilli products. A SPE procedure was optimized for the improvement of extraction efficiency and the removal of the matrix interferences such as the pigments and lipophilic compounds from hot chilli products. Under the optimum conditions, the desorbed analytes from the SPE sorbent allowed direct analysis by ESI-QTOF MS without time-consuming chromatographic separation. In the positive ion mode and MS/MS mode, linearities for concentration ranges of two orders of magnitude were obtained with the correlation coefficients (R2) greater than 0.9990; the limit of detection (LOD) and limit of quantification (LOQ) for four Sudan dyes were in the ranges of 1.1–4.3 and 3.8–14.3 ng g−1 depending on matrices, respectively. The recoveries of four Sudan dyes in two matrices ranged from 85.6 to 119.7%, with relative standard deviations (n = 4, 3) less than 11.3% and 11.6%. The developed method was successfully applied for the determination of Sudan dyes in six hot chilli products and the positive samples were confirmed with a high number of identification points (IPs) according to IPs system defined by Commission Decision 2002/657/EC.

Based on the characteristics of gas hydrate bearing permafrost in western China, and the application of alcohols drilling fluid, the performances of composite alcohol drilling fluid composed by polyethylene glycol and propylene glycol at low temperatures were comprehensively studied in this paper. The results show that the composite alcohol drilling fluid has a reasonable density, good low-temperature rheology, lubricity, shale hydration inhibition and h ydrate formation inhibition, which can effectively inhibit shale expansion in a long time, and prevent hydrate formation from a small amount of free gas released from gas hydrate decomposition around the wellbore in the circulation of drilling fluid. Therefore, the composite alcohol drilling fluid has great significance for safe and high efficiency drilling in the permafrost gas hydrate bearing formation. © 2014 The Authors. Published by Elsevier Ltd. Selection and peer-review under responsibility of Geological Engineering Drilling Technology.