超高效液相色谱法同时测定降糖类保健食品中非法添加的13 种化学药物

建立超高效液相色谱法,同时测定降糖类保健食品中可能非法添加的13 种化学药物（盐酸二甲双胍、盐酸丁二胍、盐酸苯乙双胍、甲苯磺丁脲、格列吡嗪、格列齐特、格列波脲、盐酸罗格列酮、格列本脲、盐酸吡格列酮、格列美脲、瑞格列奈、格列喹酮）。样品采用甲醇提取,经ZORBAX SB-C18色谱柱分离,乙腈和0.02 mol/L乙酸铵为流动相梯度洗脱,流速0.2 mL/min。采用二极管阵列检测器,采集波长235 nm处的色谱图进行初筛和定量。并通过与13 种降糖药物标准品的光谱比对进行确证。结果表明,13 种降糖药物在30 min内可有效分离,在0.3～90 μg/mL的线性范围内相关系数均大于0.999,平均回收率为83.2%～108.9%,相对标准偏差均不大于5.5%,检出限为0.2～0.6 ng。该方法前处理简单、分析时间相对较短、灵敏度高且重复性好,实现一个系统对13 种降糖药物的同时检测,可作为降糖类保健食品检测非法添加化学成分的参考方法。     

Bromate Formation from Bromide Oxidation by the UV/Persulfate Process

Bromate formation from bromide oxidation by the UV/persulfate process was investigated, along with changes in pH, persulfate dosages, and bromide concentrations in ultrapure water and in bromide-spiked real water. In general, the bromate formation increased with increasing persulfate dosage and bromide concentration. The bromate formation was initiated and primarily driven by sulfate radicals (SO(4)(?-)) and involved the formation of hypobromous acid/hypobromite (HOBr/OBr(-)) as an intermediate and bromate as the final product. Under the test conditions, the rate of the first step driven by SO(4)(?-) is slower than that of the second step. Direct UV photolysis of HOBr/OBr(-) to form bromate and the photolysis of bromate are insignificant. The bromate formation was similar for pH 4-7 but decreased over 90% with increasing pH from 7 to above 9. Less bromate was formed in the real water sample than in ultrapure water, which was primarily attributable to the presence of natural organic matter that reacts with bromine atoms, HOBr/OBr(-) and SO(4)(?-). The extent of bromate formation and degradation of micropollutants are nevertheless coupled processes unless intermediate bromine species are consumed by NOM in real water.     

水中SiO3^2-对红茶茶汤滋味品质的影响

通过分析SiO3^2-与主要味感物间的滋味互作效应,探究其影响茶汤滋味品质的内在机制。研究表明,随着SiO3^2-质量浓度的增加,茶汤甜味上升,鲜味、涩味、苦味及综合滋味品质下降;茶汤中儿茶素、茶多酚、氨基酸、表没食子儿茶素没食子酸酯(EGCG)含量和Ca^2+、K^+、Mg^2+等离子浸出量下降是SiO3^2-导致茶汤滋味品质下降的原因。进一步研究发现,SiO3^2-可有效增强谷氨酸钠溶液的鲜味和蔗糖溶液的甜味,显著减弱咖啡碱溶液的苦味和EGCG溶液的苦涩味,具有明显的滋味互作效应。建议日常冲泡红茶应选用含有适量SiO3^2-(<48 mg/L)的水。     

Ag nanoparticles-coated cotton fabric for durable antibacterial activity: derived from phytic acid–Ag complex

Abstract

This study focuses on the preparation of functional cotton with high and durable antibacterial activity by in situ formation of Ag nanoparticles (NPs) onto cotton fabric derived from phytic acid-Ag complex. The route can be divided into two simple steps, adsorption of silver ions onto cellulose matrix with phytic acid as a capture agent and subsequent reduction of Ag⁺ to Ag NPs by sodium borohydride. The successful deposition of Ag NPs on cotton fabric was verified by SEM, EDS and XPS. The bacterial reduction rate against E. coli and S. aureus for the as-treated fabrics was above 99%, even after 10 laundry cycles. The phytic acid was found of benefit to distribution and bonding of silver on the cotton fabric, which might lead to the enhancement of antibacterial property and durability against wash. This study may provide a green, novel and simple strategy to manufacture Ag-based antibacterial cotton for potential applications in textile industry.     

生产季节对安岳坛子肉挥发性风味物质的影响

采集1,4,7,10月生产的坛子肉作为试验样品,利用电子鼻、电子舌以及顶空固相微萃取—气相色谱—质谱联用法(HS-SPME-GC-MS)对样品中挥发性风味物质进行分析和鉴定。结果表明,各季节生产的坛子肉的风味无显著差异(P＞0.05);1月和4月坛子肉在气味上有显著差异(P＜0.05),其他坛子肉间差异不显著(P＞0.05);1月和10月坛子肉在滋味上有极显著差异(P＜0.01),而其他坛子肉间差异显著(P＜0.05)。各坛子肉中挥发性物质种类及相对含量差异较大,1月,4月,7月和10月坛子肉中分别检出53,56,73,70种挥发性物质,其中4月坛子肉的挥发性物质相对含量最高(88.60%),7月的最低(50.68%)。说明低温长时间发酵有利于坛子肉特征风味物质的形成。     

浓香型白酒中己酸检测方法研究

依据《浓香型白酒》国家标准（报批稿）中的检测方法,基于气相色谱法（GC）,通过对气相色谱条件的优化,建立了适用于浓香型白酒中己酸含量测定的检测方法。该方法精密度试验结果相对标准偏差（RSD）在1.317%～3.532%之间（n=6）,加标回收率在96.1%～102.9%之间,结果证明该方法可用于准确测定白酒中的己酸含量。     

不同品种彩粒小麦苗麦绿素提取工艺优化及其含量比较

以类黄酮、蛋白质含量和超氧化物歧化酶(Superoxide Dismutase,SOD)活性作为评价指标,试验采用水浸提法,通过单因素试验和L9(34)正交试验,考察了浸提温度、浸提时间和料液比对山农紫小麦、黑小麦031244、紫小麦204W17、黑小麦202W20 4个品种彩粒小麦苗麦绿素制备的影响,确定其提取的最佳工艺,并对其麦绿素含量进行比较。结果表明,紫小麦204W17苗麦绿素中类黄酮和蛋白质含量均最高,分别为40.21mg/100g和49.04%,其提取的最佳工艺条件为浸提温度25℃,浸提时间2.0h,浸提料液比1∶4;山农紫小麦苗麦绿素中SOD含量最高,为1865.3U/100g,其提取的最佳工艺条件为浸提温度30℃,浸提时间2.5h,浸提料液比1∶3。综合评价得出紫小麦204W17苗和山农紫小麦苗的麦绿素含量更高。     

无机盐对TiO2催化降解活性染料的影响

制备了可见光响应型纳米TiO2光催化剂,研究在无机盐存在下,TiO2对均三嗪型活性染料的光催化降解机制。结果表明,氯化钠对TiO2光催化降解活性染料既有促进作用又有抑制作用,其取决于氯化钠的浓度;硫酸钠对TiO2的光催化性能只有抑制作用,且随硫酸钠浓度的增大而增加;无机盐对X型活性染料活性艳蓝X-BR的光催化脱色没有影响,但适量的无机盐能促进K型活性艳蓝K-GR的降解。不同pH值条件下,无机盐对活性染料光催化脱色的影响不同,在酸性条件下无影响,中性和碱性条件下影响较明显,脱色率由大到小依次为:酸性>碱性>中性。     

量化筛选中国水牛奶生产Mozzarella干酪所需发酵剂

为了获得水牛奶Mozzarella干酪生产发酵剂所需菌种及其配比和用量的最佳方案,以自行筛选的保加利亚乳杆菌、嗜热链球菌、乳酸乳球菌、干酪乳杆菌为素材进行研究.通过检测所得水牛奶Mozzarella干酪样品的10项质量参数,对参数统计处理分析得到量化筛选结果,发现同时选用4个菌种、以相同的比例和3.0％的总添加量作为发酵剂制作的中国水牛奶Mozzarella干酪品质较优.