A simple method for determination of erythritol,maltitol, xylitol,and sorbitol in sugar‐free chocolates by capillary electrophoresis with capacitively coupled contactless conductivity detection

In this work, a novel and simple analytical method using capillary electrophoresis (CE) with capacitively coupled contactless conductivity detection (C⁴D) is proposed for the determination of the polyols erythritol, maltitol, xylitol, and sorbitol in sugar‐free chocolate. CE separation of the polyols was achieved in less than 6 min, and it was mediated by the interaction between the polyols and the borate ions in the background electrolyte, forming negatively charged borate esters. The extraction of the polyols from the samples was simply obtained using ultra‐pure water and ultrasonic energy. Linearity was assessed by calibration curves that showed R² varying from 0.9920 to 0.9976. The LOQs were 12.4, 15.9, 9.0, and 9.0 μg/g for erythritol, maltitol, xylitol, and sorbitol, respectively. The accuracy of the method was evaluated by recovery tests, and the obtained recoveries varied from 70 to 116% with standard deviations ranging from 0.2 to 19%. The CE‐C⁴D method was successfully applied for the determination of the studied polyols in commercial samples of sugar‐free chocolate.     

Antioxidant and toxicological evaluation of a Tamarindus indica L. leaf fluid extract

In the scientific community, there is a growing interest in Tamarindus indica L. leaves, both as a valuable nutrient and as a functional food. This paper focuses on exploring its safety and antioxidant properties. A tamarind leaf fluid extract (TFE) wholly characterised was evaluated for its anti-DPPH activity (IC₅₀ = 44.36 μg/mL) and its reducing power activity (IC₅₀ = 60.87 μg/mL). TFE also exhibited a high ferrous ion-chelating capacity, with an estimated binding constant of 1.085 mol L^? 1 while its influence over nitric oxide production in human leucocytes was irregular. At low concentrations, TFE stimulated NO output, but it significantly inhibited it when there was an increase in concentration. TFE was also classified as a non-toxic substance in two toxicity tests: the acute oral toxicity test and the oral mucous irritability test. Further toxicological assays are needed, although results so far suggest that TFE might become a functional dietary supplement.     

A review on biological sources,chemistry and pharmacological activities of pinostrobin

Pinostrobin, a dietary bioflavonoid discovered more than 6 decades ago in the heart-wood of pine (Pinus strobus), has depicted many pharmacological activities including anti-viral, anti-oxidant, anti-leukaemic, anti-inflammatory and anti-aromatase activities. It is an inhibitor of sodium channel and Ca²⁺ signalling pathways and also inhibits intestinal smooth muscle contractions. In spite of the fact that pinostrobin has an application as functional foods, till-to-date no comprehensive review on pinostrobin has been carried out. Hence, the present review deals with the biological sources, chemistry and pharmacological activities of pinostrobin.     

红外烤漆机理及轮毂模拟烤漆实验研究

我国汽车、拖拉机及家电等行业的烤漆装机功率约为１６０万ｋＷ,能耗大、能源利用率低而质量差,工件不干亟待解决．文中阐述了红外强化烤漆的机理并利用新研制的高温定向电阻带辐射器对汽车轮毂进行了强化模拟烤漆实验研究并进行了理论计算,结果表明高温定向近距离辐射及优化布置辐射器是缩短烤漆周期、节约能源及确保烤漆质量的重要途径之一．     

Ionic liquids as mobile phase additives in high-performance liquid chromatography with electrochemical detection: Application to the determination of heterocyclic aromatic amines in meat-based infant foods

The beneficial effects of several ionic liquids (ILs) as mobile phase additives in high-performance liquid chromatography with electrochemical detection for the determination of six heterocyclic aromatic amines (HAs) have been evaluated for first-time. The studied ionic liquids were 1-butyl-3-methylimidazolium tetrafluoroborate (BMIm-BF₄), 1-hexyl-3-methylimidazolium tetrafluoroborate (HMIm-BF₄) and 1-methyl-3-octylimidazolium tetrafluoroborate (MOIm-BF₄). Several chromatographic parameters have been evaluated in the presence or absence of ILs, or using ammonium acetate as the most common mobile phase additive, with three different C18 stationary phases. The effect of the acetonitrile content was also addressed. In general, best resolution, lower peak-widths (up to 72.1% lower) and lower retention factors are obtained when using ILs rather than ammonium acetate as mobile phase additives. The main improvement was obtained in the baseline noise, being 360% less noisy for BMIm-BF₄, 310% for HMIm-BF₄, and 227% for MOIm-BF₄, when compared to ammonium acetate at +1000 mV. Different chromatographic methods using the best conditions for each IL were also evaluated and compared. Finally, the best chromatographic conditions using 1 mM of BMIm-BF₄ as mobile phase additive, the Nova-Pak^® C18 column, 19% (v/v) of acetonitrile content in the mobile phase, and +1000 mV in the ECD, have been applied for the chromatographic analysis of six HAs contained in meat-based infant foods. The whole extraction method of meat-based infant foods using focused microwave-assisted extraction and solid-phase extraction has also been optimized. Extraction efficiencies up to 89% and detection limits ranged between 9.30 and 0.165 ng g⁻¹ have been obtained under optimized conditions.     

动物源性食品中四环素类残留分析研究进展

综述了检测动物源性食品中四环素类残留的前处理方法,包括固相萃取、固相微萃取、基质分散技术、分子印迹技术、限进介质材料;对高效液相色谱、毛细管电泳、微生物法和酶联免疫分析等在四环素类药物中的检测应用进行了综述,比较了各种方法的优缺点。     

常见食品中邻苯二甲酸酯类增塑剂含量及食品包装材料中邻苯二甲酸酯类增塑剂迁移量的测定

采用气相色谱-质谱联用(GC-MS)方法并结合液液萃取及基质分散固相萃取的样品处理方式,建立了测定饮料、牛奶、白酒3类食品中16种邻苯二甲酸酯类增塑剂的分析方法。研究结果表明16种邻苯二甲酸酯类增塑剂的检出限(LOD, S/N=3)范围为0.005~0.025 mg/L;峰面积的相对标准偏差(RSD)均小于2%。饮料、牛奶、白酒3种样品的加标回收率范围普遍在60%~110%。所建方法简便、灵敏、准确,可满足饮料、牛奶和白酒中痕量邻苯二甲酸酯类增塑剂的测定需要。此外,将该方法应用于食品包装材料中邻苯二甲酸酯类增塑剂的迁移研究,以异辛烷为油脂食品模拟物,测定了保鲜膜与保鲜袋中16种邻苯二甲酸酯类增塑剂的迁移量。结果显示保鲜膜存在显著的邻苯二甲酸酯类增塑剂迁移现象。     

前体离子扫描法在快速筛查中药及保健食品中非法添加的5型磷酸二酯酶抑制剂及其未知衍生物中的应用

改造有明确疗效的药物,合成新的衍生物以避开法定检验方法是目前化学药物非法添加的趋势之一。本文提出将液相色谱-三重四极杆质谱联用仪的质谱前体离子扫描模式应用于中药及保健食品等复杂体系中非法添加药物衍生物的快速筛查策略,以5型磷酸二酯酶抑制剂为实验对象,通过分析该类化合物的结构和质谱特点将其分类,筛选各类共有的子离子碎片,优化质谱参数,建立了前体离子扫描模式的LC-MS筛查方法,讨论了质谱参数和碎片离子的选择对筛选结果的影响,并应用于实际样品的测定。结果表明,该方法既可以满足已知化合物的测定需要,又可以对复杂体系中未知的同类衍生物进行快速筛查,防止未知衍生物的漏检。该方法灵敏、专属、高效,值得进一步研究。