超高效液相色谱-串联质谱法测定白酒中9种甜味剂

目的建立准确、快速检测白酒中安赛蜜、糖精钠、甜蜜素、阿斯巴甜、三氯蔗糖、纽甜、阿力甜、甜菊糖苷和甜菊双糖苷9种甜味剂的超高效液相色谱-串联质谱分析方法。方法样品经沸水浴加热除去乙醇,采用超高效液相色谱-串联质谱法进行检测。以水(含10 mmol/L乙酸铵)和甲醇为流动相, HSS T3色谱柱(2.1 mm×100 mm,1.7μm)进行分离,电喷雾离子化多反应监测模式检测。结果 9种甜味剂在相应线性范围内关系良好,相关系数均≥0.999;方法回收率为85.2%～102.8%,相对标准偏差(RSD)为3.8%～7.3%;检出限为0.3～1.5μg/kg。结论该方法操作简单快速、重现性好,可用于白酒中9种甜味剂的检测。     

高效液相色谱-蒸发光散射检测器同时测定食品中5种甜味剂

建立了高效液相色谱-蒸发光散射检测器同时测定食品中安赛蜜、糖精钠、甜蜜素、三氯蔗糖、阿力甜5种甜味剂的方法.样品中的甜味剂提取后经固相萃取净化, 并通过C18柱分离, 蒸发光散射检测器测定.结果表明5种甜味剂在5～160 mg/L的浓度范围内, 相关系数为0.9991～0.9994;方法回收率为92.0%～97.0%, 相对标准偏差为0.67%～3.23%.方法最低检出限:安赛蜜为2 mg/kg, 糖精钠为2.5 mg/kg, 甜蜜素、阿力甜和三氯蔗糖为5 mg/kg.该方法准确、灵敏, 是同时检测食品中5种甜味剂的有效方法.     

超高效液相色谱法测定乳制品中安赛蜜、糖精钠、阿斯巴甜、阿力甜、纽甜、甜菊糖苷

建立乳制品中安赛蜜、糖精钠、阿斯巴甜、阿力甜、纽甜、甜菊糖苷的超高效液相色谱测定方法。样品经固相萃取柱净化后,梯度洗脱,在10min内完成分离,外标法定量,得出了6种甜味剂在不同乳制品中的检出限和定量限。方法操作简便,灵敏度高,适用于4种基质中6种甜味剂的快速检测。     

超高效液相色谱串联质谱同时测定酒类产品中多种人工合成甜味剂

建立超高效液相色谱-电喷雾电离串联质谱（ultra performance liquid chromatography-electro spray ionizationtandem mass spectrometry,UPLC-ESI-MS-MS）同时测定酒类产品中安赛蜜、糖精钠、甜蜜素、三氯蔗糖、阿斯巴甜、阿力甜和纽甜人工合成甜味剂的分析方法。方法采用ZORBAX Eclipse XDB-C18柱（100 mm×4.6 mm,1.8 μm）色谱柱,柱温50 ℃。流动相由A（甲醇）和B（体积分数0.1%甲酸和20 mmol/L甲酸铵溶液,pH 4.0）组成,流速为0.5 mL/min,梯度洗脱。在ESI负离子模式下,采用多反应监测模式进行测定,可以在12.5 min内完成7 种人工合成甜味剂的检测。安赛蜜、糖精钠、甜蜜素、三氯蔗糖、阿斯巴甜、阿力甜和纽甜在10～5 000 μg/L范围内有良好的线性关系,相关系数大于0.999。安赛蜜、糖精钠、甜蜜素、三氯蔗糖、阿斯巴甜、阿力甜和纽甜检出限分别为4、6、4、8、4、4、2 μg/L,回收率在88.3%～98.3%之间,相对标准偏差为2.1%～6.7%。该方法快速、准确,灵敏度高,适用于酒类产品中低含量人工合成甜味剂的测定。     

甜味剂的市场现状与复配意义

近年来,由于蔗糖价格的不断上涨,以及人们饮食观念的改变（追求低热量的食品）,甜味剂替代蔗糖的趋势日益显著。甜味剂是赋予食品甜味的一类十分重要的食品添加剂,由于它甜度高,且热量低．市场前景非常广阔。目前世界上允许使用的单体甜味剂约有20多种。主要有甜蜜素、三氯蔗糖、K糖（安赛蜜）、阿斯巴甜、阿力甜、纽甜、糖精、甘草甜素、甜菊苷、罗汉果甜苷和索马甜等。     

超高效液相色谱-质谱仪联用同时检测食品中7种甜味剂

本文建立了一种使用超高效液相色谱仪和三重四极杆质谱仪联用检测安赛蜜、糖精钠、甜蜜素、甜菊糖苷、纽甜、三氯蔗糖和阿斯巴甜七种甜味剂的测试方法。样品经处理后,用超高效液相色谱在5.0 min内完成分离,三重四极杆质谱仪进行定量分析。验证了七种甜味剂的检出限、定量限。     

白酒中常见的7种甜味剂检测方法及来源的研究进展

对白酒中常见的7种甜味剂(安赛蜜、糖精钠、甜蜜素、三氯蔗糖、纽甜、阿斯巴甜和甜菊糖苷)的特性、常见检测方法及可能来源进行了论述,并对市场上白酒的监管提出了建议。     

液相色谱-串联质谱法同时测定食品中9种甜味剂

建立了高效液相色谱-串联质谱法同时测定食品中9种甜味剂(安赛蜜、糖精钠、甜蜜素、阿斯巴甜、三氯蔗糖、阿力甜、甜菊糖苷、爱德万甜和纽甜)含量的分析方法。样品经超声、离心等前处理后过0.22μm滤膜后上机分析。采用AQ-C18(100 mm×2.1 mm×3μm)为分离柱,c(乙酸铵)为20 mmol/L的水溶液-φ(甲酸)为0.1%的乙腈溶液为流动相,梯度洗脱,在ESI负离子模式下,采用多反应监测模式进行测定,以质量数和保留时间定性、峰面积定量。结果表明,9种甜味剂在工作曲线范围内相关系数均大于0.9990,方法检出限在0.020~0.055 mg/kg,食品加标回收率为90.6%~111.5%,其相对标准偏差(n=6)均小于6.0%。应用此方法对食品(白酒、饮料、果冻、酸奶、糖果)中9种甜味剂进行检测,前处理步骤简单,测定快速、准确度和灵敏度高,能满足国家标准对食品中9种甜味剂的分析要求,与国家标准方法相比,提高了分析效率。     

超高效液相色谱串联质谱法同时测定白酒中6种人工合成甜味剂的方法研究

建立了超高效液相色谱串联质谱仪同时测定白酒中6种甜味剂(安赛蜜、糖精钠、甜蜜素、三氯蔗糖、阿斯巴甜和纽甜)的分析方法。白酒样品经80℃水浴加热处理后,用超纯水定容,经0.2μm滤膜过滤后上机分析。采用C_(18)柱分离,以乙腈-1‰甲酸水溶液为流动相,梯度洗脱,以质量数和保留时间定性、峰面积定量。结果表明,6种甜味剂的浓度与其峰面积在0~5 mg/L范围内呈良好线性关系,平均回收率97.4%~108.7%,RSD值1.9%~3.5%,安赛蜜、甜蜜素、阿斯巴甜的检出限为0.01 mg/L,糖精钠、纽甜、三氯蔗糖的检出限为0.02 mg/L。     

超高压液相色谱—质谱同时测定白酒中6种微量甜味剂的方法研究

为了检测白酒中6种甜味剂(安赛蜜、糖精钠、甜蜜素、三氯蔗糖、阿斯巴甜、纽甜),建立了一种超高压液相色谱质谱联用的新方法。样品预处理后,通过BEH C-18色谱柱分离,以甲醇-20 mmol/L乙酸铵水溶液为流动相进行梯度洗脱,在ESI负离子模式下检测,一次进样分析仅需10 min。以优化后的条件进行测定,6种甜味剂线性范围均在0.05~5.0 mg/L内,线性相关系数均大于0.994 5。得到安赛蜜检出限为0.05 mg/L、糖精钠、甜蜜素、纽甜检出限为0.01 mg/L、三氯蔗糖、阿斯巴甜检出限为0.1 mg/L。加标水平为0.5 mg/L和1.0 mg/L时,回收率在86.48%~116.90%之间,相对标准偏差为0.22%-3.90%。方法准确可靠、简便快速、可达到同时检测6种甜味剂的目的。     

褪黑素对小鼠抗氧化作用的影响

目的:研究小鼠在受到脂多糖(LPS)刺激时,褪黑素的抗氧化作用,并探讨其可能机制。方法:用脂多糖建立氧化应激模型,检测血清、小肠、肝脏和脾组织中的ROS含量,肝脏、脾组织中的谷胱甘肽过氧化物酶(GSH-PX)、超氧化物歧化酶(SOD)、丙二醛(MDA)的变化。结果:在LPS刺激后的4h和16h,褪黑素均能降低血清、小肠、肝脏、脾组织中的ROS含量,提升肝脏和脾组织中的GSH-PX、SOD活性,降低MDA含量。结论:褪黑素有助于增强氧化应激小鼠的抗氧化能力,降低组织中NO含量与NO合成酶活性,增加了SOD、GSH-PX等抗氧化酶的活性,保护机体免受氧化损伤。     

Determination of the variability of both hydrophilic and lipophilic toxins in endemic wild bivalves and carnivorous gastropods from the Southern part of Chile

The aim of this study was to analyse and determine the composition of paralytic shellfish poisoning (PSP) toxins and lipophilic toxins in the Region of Aysén, Chile, in wild endemic mussels (Mytilus chilensis, Venus antiqua, Aulacomya ater, Choromytilus chorus, Tagelus dombeii and Gari solida) and in two endemic carnivorous molluscs species (Concholepas concholepas and Argobuccinum ranelliforme). PSP-toxin contents were determined by using HPLC with fluorescence detection, while lipophilic toxins were determined by using LC-MS/MS. Mean concentrations for the total of PSP toxins were in the range 55–2505 μg saxitoxin-equivalent/100 g. The two most contaminated samples for PSP toxicity were bivalve Gari solida and carnivorous Argobuccinum ranelliforme with 2505 ± 101 and 1850 ± 137 μg saxitoxin-equivalent/100 g, respectively (p < 0.05). The lipophilic toxins identified were okadaic acid, dinophysistoxin-1 (DTX-1), azaspiracid-1 (AZA-1), pectenotoxin-2 (PTX-2) and yessotoxins (YTX). All analysed molluscs contained lipophilic toxins at levels ranging from 56 ± 4.8 to 156.1 ± 8.2 μg of okadaic acid-equivalent/kg shellfish together with YTX at levels ranging from 1.0 ± 0.1 to 18 ± 0.9 μg of YTX-equivalent/kg shellfish and AZA at levels ranging from 3.6 ± 0.2 to 31 ± 2.1 μg of AZA-equivalent/kg shellfish. Furthermore, different bivalves and gastropods differ in their capacity of retention of lipophilic toxins, as shown by the determination of their respective lipophilic toxins levels. In all the evaluated species, the presence of lipophilic toxins associated with biotransformation in molluscs and carnivorous gastropods was not identified, in contrast to the identification of PSP toxins, where the profiles identified in the different species are directly related to biotransformation processes. Thus, this study provides evidence that the concentration of toxins in the food intake of the evaluated species (Bivalvia and Gastropoda class) determines the degree of bioaccumulation and biotransformation they will thereafter exhibit.     

高效液相色谱法同时检测6种甜味剂

建立同时测定6种人工合成甜味剂阿斯巴甜、糖精钠、甜蜜素、安塞蜜、纽甜、甜聚糖甙的高效液相色谱分析方法。以Platicil ODS柱为分离柱,20mmol/L硫酸铵缓冲溶液(pH4.4)-乙腈为流动相,进行梯度洗脱。采用二极管阵列检测器进行检测,整个分离过程在30min内完成。6种甜味剂在0.4～120mg/L范围内其质量浓度与峰面积的线性关系良好,相关系数为0.99967～0.99998,在4.0～10.0mg/kg范围内,样品加标回收率为85%～107%;相对标准偏差小于3.2%。该方法简便、快速,净化效果较好,可用于食品中6种甜味剂的同时测定。     

气相色谱法检测饮料中二羰基化合物

建立同时在线检测丙酮醛和乙二醛的气相色谱方法。确定检测二羰基化合物的最佳条件为：以丁二酮为内标,以邻苯二胺为衍生化试剂,邻苯二胺的用量67 倍于二羰基化合物、衍生化时间10 min、萃取溶剂二氯甲烷、超声时间15 min、萃取2 次、柱箱初始温度40 ℃、程序升温5 ℃/min,色谱柱载气流量2.0 mL/min,分流比1∶1。丙酮醛和乙二醛的定量限（RSN≈10）分别为0.06 mg/L和0.08 mg/L,检出限（RSN≈ 3）分别为0.02 mg/L和0.03 mg/L,方法灵敏度高。     

盐胁迫对芦荟几项生理生化指标的影响

以常规库拉索芦荟为对照 ,检测经不同浓度海水灌溉 3a的库拉索芦荟的几项生理生化指标的变化。结果表明 ,盐胁迫对芦荟全叶原汁的吸光度、pH值、相对密度、总固形物、水分含量和镁离子含量的影响较小 ,但对多糖和钙离子含量的影响较大。 2 5 %或 5 0 %海水灌溉的芦荟中多糖含量很高 ,增加了 2～ 3倍 ;低浓度海水灌溉下 ,芦荟中钙离子含量高于对照 (CK) ;而在高浓度海水灌溉下 ,芦荟中钙离子含量则低于CK。在盐胁迫下 ,芦荟体内积累一定量丙二醛 ,而脯氨酸含量则下降 ;过氧化物酶活力先在低盐条件下显著提高 ,随后则下降 ,与CK相当 ;过氧化氢酶活力随海水浓度的提高而迅速下降 ;超氧物歧化酶活力受盐浓度影响不大 ,基本上趋于稳定。     

对药剂敏感性不同的烟蚜体内几种关键性酶活性的比较分析

对吡虫啉和氧化乐果在三明地区和合肥地区烟蚜的毒力进行了测定,并对两地烟蚜的羧酸酯酶、乙酰胆碱酯酶和谷胱甘肽转移酶的活性进行了研究.结果表明吡虫啉对两地烟蚜的生物活性远高于氧化乐果,三明烟蚜对两种药剂的敏感性都比合肥烟蚜的低,三明烟蚜种群的毒力方程b值低,存在一定的异质性;两地烟蚜的羧酸酯酶、乙酰胆碱酯酶活性差异不显著,但三明地区烟蚜的谷胱甘肽转移酶活性显著高于合肥地区烟蚜.     

Correlation of methylglyoxal with acrylamide formation in fructose/asparagine Maillard reaction model system

α-Dicarbonyl compounds were highly reactive intermediates formed in Maillard reaction (MR), and o-phenylenediamine (OPD) was widely used as a trapping agent for α-dicarbonyl compounds. Both aqueous fructose/asparagine (Fru/Asn) and fructose/asparagine/o-phenylenediamine (Fru/Asn/OPD) model systems were heated at 150 °C for up to 30 min. Methylglyoxal (MG) was the main α-dicarbonyl compounds formed in MR, which was chosen as a representative of α-dicarbonyl compound to investigate the influence on acrylamide (AA) formation. The concentrations of AA, MG and Asn were detected during MR by HPLC method. The results indicated that the formation of AA increased with the heating time, and nearly 75% of AA was formed through the participation of α-dicarbonyl compounds. The amounts of formation and consumption of MG increased with heating time, and from 12 min of reaction, the consumed amounts of MG accounted for 62.1–90.3% on the basis of total amounts of MG formed in MR, suggesting that most of the MG took part in further reactions. Meanwhile, Asn concentration decreased with heating time in both models. The formation of AA and consumption of Asn were highly correlated with MG. Indeed, as MG concentration in MG/Asn model system decreased during heating at 150 °C, the concentration of AA significantly increased. The coefficient of correlation between consumed amounts of MG and the formed amounts of AA was 0.931, demonstrating that MG plays a role in AA formation.     

亚甲基蓝对单增李斯特菌菌膜的光动力杀伤作用

探讨单增李斯特菌（Listeria monocytogenes,LM）生物菌膜的生长特性及亚甲基蓝对LM生物菌膜光动力杀伤作用。通过结晶紫染色法判断与观察LM生物菌膜的形成并用酶标仪在595 nm波长处对其不同生长阶段的生物量进行测定,同时通过细菌平板菌落计数法研究亚甲基蓝对LM生物菌膜的光动力杀伤作用。结果表明：结晶紫染色法可用于定性判断与观察LM生物菌膜,且随着培养时间的延长,LM生物菌膜生物量不断增加,形成的网状结构越来越致密。当光敏剂质量浓度为10 μg/mL的亚甲基蓝在光功密度为200 mW/cm2 的可见光照射30 min时,即可使LM生物菌膜的失活率达到99.99%以上,其菌落数降低了4.08（lg（CFU/mL））。亚甲基蓝对LM生物菌膜的光动力灭活作用非常显著,其杀伤效果主要取决于光敏剂质量浓度和光照时间。     

嘧菌酯处理对厚皮甜瓜POD和CAT活性的影响

以厚皮甜瓜(Cucumis melonL.)作为实验材料,研究嘧菌酯处理对厚皮甜瓜采后过氧化物酶和过氧化氢酶活性的影响,实验结果表明:甜瓜经50、100、200mg/L嘧菌酯浸泡处理后,其果实的过氧化物酶和过氧化氢酶活性均有所变动,其中,100mg/L嘧菌酯处理,两种酶的活性均处于稳定上升趋势,到第14天达到最高值,此后呈下降趋势,但到第21天时,酶活性仍高于对照。     

Analysis of carbohydrates in seven edible fruits of Bangladesh

Dry matter, ash, lignin, starch and soluble and insoluble dietary fibre contents of the edible parts of seven fruits of Bangladesh were determined. Analysis of the low molecular weight carbohydrates showed that all the fiuits, except lukluki and hogplum, contained substantial amounts of these materials of which glucose and fiuctose were the main components. The main constituent of the polysaccharides in all the fruits was glucose. The dietary fibre contents of the dry fruits ranged from 29% to 79%. Lukluki has by far the best combination of low fiee sugars and high dietary fibre, and pineapple the worst.