Determining Neu5Ac in infant formula with ultra‐performance liquid chromatography–tandem mass spectrometry

The aim of this work was to measure N‐acetylneuraminic acid (Neu5Ac) in milk‐based infant formulas. The analysis was performed by ultra‐performance liquid chromatography–tandem mass spectrometry (UPLC‐MS/MS). The total Neu5Ac were released using trichloroacetic acid and hydrochloric acid and purified using a HLB column. The linearity from 0.05 to 5.0 μg/mg Neu5Ac was adequate. Sialic acid recoveries ranged from 91.8% to 112.4%. The detection and quantification limits (limit of detection, 0.01 μg Neu5Ac/mg; limit of quantitation, 1.08 μg Neu5Ac/mg) were low enough to determine the sialic acid in infant formulas. The validated method is highly reproducible and sensitive, and it is easy to perform.     

基于RFID和视觉的工业机器人系统应用与实践

结合当前工业机器人在生产中的应用,针对全国职业院校技能大赛新赛项——工业机器人与视觉技术,对大赛设备软硬件系统作了详细的介绍和分析,着重阐述了RFID、视觉系统、工业机械手和FX3UPLC之间的通信、采用的重要关键技术及系统调试完成步骤,有助于提高工业机器人系统的应用能力,并为较顺利地参加技能大赛和开拓学习思路提供帮助。     

Saturated aqueous ozone degradation of deoxynivalenol and its application in contaminated grains

Deoxynivalenol (DON) is a secondary metabolite produced by Fusarium graminearum in grains, food and contaminated feed, which can lead to many adverse health effects to humans and livestock. The degradation of DON in different contaminated grains oxidated by saturated aqueous ozone (80 mg L⁻¹) was monitored by ultra-high-performance liquid chromatography, tandem-quadrupole-detection mass spectrometry (UPLC–TQD-MS). Results suggest that ozone has a significant effect on DON reduction in solution. When 80 mg L⁻¹ gaseous ozone was used to treat 10 mg L⁻¹ of DON solution, the degradation rate of DON reached 83% within 7 min, while the respective detoxification rates of contaminated wheat, corn and bran by saturated aqueous ozone (80 mg L⁻¹) were 74.86%, 70.65% and 76.21 in 10 min. Ozone at 80 mg L⁻¹ was applied on various DON solution concentrations at 1 mg L⁻¹, 10 mg L⁻¹ and 20 mg L⁻¹ in ultra-pure water. In this paper, the degradation procedure for DON is calculated and described by a first-order kinetic equation. At lower levels (20 mg L⁻¹) of aqueous ozone, intermediate degradation products were observed by ultra-ne quickly and effectively degrades DON and toxicity in various contaminated grains in a matter of minutes. Therefore, ozonation is projected to be an effective, fast, and safe method for DON degradation.     

超高效液相色谱法测定乳及乳制品中多种磺胺类药物残留

建立了超高效液相色谱法同时测定乳及乳制品中14种磺胺类药物残留的方法.样品通过乙腈重复提取,饱和正己烷脱脂后浓缩,基质固相分散萃取技术净化,采用ACQUITY UPLCTM BEH C18柱,以甲醇和质量分数0.1％甲酸水溶液为流动相梯度洗脱,用紫外检测器于270 nm波长处检测.回收率在90.4％～104.3％,精密度(RSD)为1.09％～5.73％,检出限分别为0.04～0.09 μg/g.该方法可用于乳及乳制品中14种磺胺类药物残留的同时测定.     

超高效液相色谱法快速测定竹叶青酒中栀子苷的含量

建立了一种快速测定竹叶青酒中栀子苷含量的超高效液相色谱分析方法。使用ACQUITY UPLC BEH C18（1.7μm,2.1×50mm）色谱柱,以乙腈-水（10∶90,V/V）为流动相,采用紫外检测器（检测波长238nm）对竹叶青中的栀子苷进行测定。结果表明,在24~960mg/ml范围内竹叶青酒中栀子苷含量与峰面积呈良好的线性关系,相关系数r=0.999986,精密度和稳定性试验相对标准偏差均小于5%,加样回收率达到99.43%。该测定方法简单、准确、精密度高、重现性好,且分析速率大大提高。     

Approaches to the evaluation of matrix effects in the liquid chromatography-mass spectrometry (LC-MS) analysis of three regulated lipophilic toxin groups in mussel matrix (Mytilus edulis)

Liquid chromatography coupled to mass spectrometry (LC-MS) is seen as an integral part of methods of choice for the replacement of animal tests in the determination of lipophilic shellfish toxins. However, these techniques are prone to matrix effects that need to be considered when developing and validating methods. The analysis of shellfish is a challenging task due to the complexity of the shellfish matrix and the number of shellfish species encountered in monitoring laboratories. Therefore, it is crucial that the cause and the extent of matrix effects is fully understood in order to apply corrective measures to the analytical method and to develop efficient sample clean-up steps. This paper presents different approaches to evaluate matrix effects associated with the analysis of okadaic acid (OA), azaspiracid-1 (AZA1) and pectenotoxin-2 (PTX2) in cooked and raw mussel flesh. Post-extraction addition and standard addition experiments were carried out and analysed using various LC-MS methods. Gradient and isocratic elution were compared and ultra-performance liquid chromatography (UPLC), using C8 and C18 Acquity BEH columns, was evaluated for the extent of matrix effects. When matrix effects were observed, OA and PTX2 were always prone to signal enhancement and AZA1 to signal suppression. For all the toxins studied, matrix effects were dependent on chromatographic conditions. UPLC separation using a C8 column significantly reduced matrix effects compared to the other conditions assessed. Furthermore, sample dilution has proven to be an efficient way of reducing matrix effects associated with OA analysis.     

Effect of fermented soybean product (Cheonggukjang) intake on metabolic parameters in mice fed a high‐fat diet

As a nontargeted metabolomics approach, we investigated changes in the plasma metabolite levels in a mouse model of obesity induced by a high‐fat diet and fermented soybean product diet. We analyzed the plasma samples by using ultra‐performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry (UPLC‐Q‐TOF‐MS). In the present study, the animals were divided into four groups according to the diet type; normal fat diet control group (ND), high‐fat diet control group (HD), high‐fat diet plus 30% cooked soybean power (HD + S), and high‐fat diet plus 30% 72‐h fermented Cheonggukjang powder (HD + CGJ). To examine the changes in plasma metabolite levels because of high‐fat diet feeding, total cholesterol and triglyceride levels were measured. Total cholesterol and triglyceride levels were lower in the HD + S and HD + CGJ groups than in the ND group. According to partial least‐squares discriminant analysis (PLS‐DA), major metabolites contributing to the discrimination between each group were assigned as lipid metabolites in plasma, e.g., lyso‐phosphatidylcholines and phosphatidylcholines. Therefore, diets containing soy‐based food products, which are rich sources of isoflavonoids, might be helpful for controlling the lipid metabolism under high‐fat diet conditions.     

超高压液相色谱法同时检测玉米中的伏马毒素B1、B2、B3

目的 综合比较伏马毒素4种柱前衍生[邻苯二甲醛(OPA)、萘-2,3-二甲醛(NDA)、丹磺酰氯、6-氨基喹啉-N-羟基琥珀酰亚胺氨基甲酸酯(AQC)]效果的优劣, 并选择一种衍生剂用于玉米样品中伏马毒素B1(FB1)、B2(FB2)、B3(FB3)的检测, 建立柱前衍生-超高压液相色谱法同时测定玉米中伏马毒素B1、B2和B3的方法。方法 采用乙腈-水(50∶50, v/v)溶液提取玉米中的伏马毒素B1、B2和B3, 涡旋震荡及离子交换柱净化对玉米样品中的伏马毒素B1、B2和B3进行提取与净化, 经衍生后进行超高压液相色谱-荧光检测器检测。 结果 最终选择OPA衍生作为本研究的衍生方法。3种伏马毒素的线性范围分别为50~1000 ng/mL、25~500 ng/mL、25~500 ng/mL, 相关系数R2均大于0.999; 最低定量限LOQ分别为25.0、14.0、17.0 μg/kg; 3个浓度的加标回收率分别为(75.6?1.6)%~(83.4?2.3)%, (78.9?5.4)%~(90.0?0.7)%, (83.7?8.2)%~(88.6?1.0)%; FB1、FB2和FB3的日间精密度分别为3.62%、3.41%、4.77%。结论 该方法具有预处理简单、检测速度快、灵敏度高的优点, 可满足对玉米中>800 μg/kg伏马毒素含量的检测要求。流动相的改进及梯度洗脱的使用, 提高了检测的灵敏度, 并可被在具有液相色谱仪的实验室应用。     

UPLC-FLD检测玩具涂料中的多环芳烃

采用超高效液相色谱-荧光检测器(UPLC-FLD)检测玩具涂料中的多环芳烃,通过条件优化,实现了各组分的完全分离和高灵敏度检测。在优化的实验条件下,荧光检测器的检出限为0.015～0.8μg/mL,方法精密度为0.6%～1.45%,样品加标回收率为78.5%～100.5%。与气相色谱质谱联用仪相比,该方法有更快的检测速度和更高的灵敏度,适合于玩具涂料生产过程和原材料等的快速检测。