超高效液相色谱法同时快速测定陈年道菜中安赛蜜、苯甲酸、山梨酸、糖精钠、脱氢乙酸

建立了一种同时快速测定陈年道菜中安赛蜜、苯甲酸、山梨酸、糖精钠、脱氢乙酸的超高效液相色谱法。样品前处理后,经Agilent Ecilpse Plus C18(50mm×2.1mm,1.8μm)色谱柱分离,以甲醇-20mmol/L乙酸铵的乙酸溶液(pH 5.28)为流动相进行梯度洗脱,采用二极管阵列检测器,检测波长为230nm,流速为0.30mL/min,柱温为40℃,以保留时间定性,外标法峰面积定量。结果表明,安赛蜜、苯甲酸、山梨酸、糖精钠、脱氢乙酸在5min内可以完全分开,样品在0.02～0.10g/kg添加三水平范围内的回收率在66.43%～102.87%之间,相对标准偏差小于3.2%。该方法快速准确,分离效果好,适用于陈年道菜中安赛蜜、苯甲酸、山梨酸、糖精钠、脱氢乙酸的快速检测。     

超高效液相色谱法同时测定饮料中的山梨酸、苯甲酸、脱氢乙酸、糖精钠和安赛蜜

目的建立用超高效液相色谱法(ultra performance liquid chromatography,UPLC)同时测定饮料中的山梨酸、苯甲酸、脱氢乙酸、糖精钠和安赛蜜的分析方法。方法样品中山梨酸、苯甲酸、脱氢乙酸、糖精钠和安赛蜜用水提取,经BEH C_(18)柱(2.1 mm×100 mm,1.7μm)分离,在波长225 nm处检测。结果此方法的线性范围是5~100μg/mL,回收率为95.5%~100.2%,相对标准偏差(relative standard deviation,RSD)为1.0%~3.1%。结论此方法简便快速,准确可靠,灵敏度高,可用于同时检测饮料中的山梨酸、苯甲酸、脱氢乙酸、糖精钠和安赛蜜。     

RP-HPLC法同时测定糕点中安赛蜜、苯甲酸、山梨酸、糖精钠和脱氢乙酸

建立反相高效液相色谱法(RP-HPLC同时测定糕点中安赛蜜、苯甲酸、山梨酸、糖精钠和脱氢乙酸。该方法糕点样品经处理后,采用SunFire C185μ4.6 mmmm反相色谱柱,流动相为甲醇:磷酸盐缓冲液(pH6.7=793等度洗脱,流速为1.0 mL/min检测波长230 nm柱温为30℃进样量为20μ。线性范围0.2 mg/L120 mg/L检出限0.4 mg/kg1.0 mg/kg加标回收率为87.7%105.3%相对标准偏差小于5%。结果表明,该方法操作简便、结果可靠,可用于同时检测糕点中安赛蜜、苯甲酸、山梨酸、糖精钠和脱氢乙酸。     

气相色谱内标法测定食品中防腐剂脱氢乙酸、苯甲酸和山梨酸

选用正十一烷酸为内标,采用毛细管气相色谱内标法测定食品中防腐剂脱氢乙酸、苯甲酸和山梨酸,样品回收率均在96％～104％之间,标准线性关系良好,样品测定的变异系数小,脱氢乙酸为0.71％,苯甲酸为0.82％和山梨酸为0.62％;本方法具有简便、快速、准确的特点。     

HPLC法同时测定复合食品防腐剂中苯甲酸、山梨酸和脱氢乙酸

应用高效液相色谱法测定复合食品防腐剂中苯甲酸、山梨酸和脱氢乙酸的含量。样品用水提取后,甲醇和0.02mol/L乙酸铵15∶85(v/v)为流动相洗脱,经Syncronis aQ(4.6mm×150mm,5μm)色谱柱分离,二极管阵列检测器检测,检测波长为225nm。苯甲酸、山梨酸和脱氢乙酸的质量浓度在2 50mg/L的范围内与其峰面积成线性关系,线性方程分别为y=38273x-8760.9、y=48559x+10538、y=52126x+4283.4,检出限均为0.1mg/L。苯甲酸平均回收率为98.8%101.0%,相对标准偏差≤1.8%(n=6);山梨酸平均回收率为97.5%100.1%,相对标准偏差≤2.2%(n=6);脱氢乙酸平均回收率为99.5%101.0%,相对标准偏差≤2.2%(n=6)。该方法精确度和准确性好、灵敏度高,样品预处理简单,避免了滴定分析方法中复配防腐剂之间相互干扰的问题,是复合食品防腐剂中各种成分含量测定的理想检测方法。     

高效液相色谱法测定月饼中3种防腐剂

利用高效液相色谱法测定5种月饼样品中的3种常见防腐剂苯甲酸、山梨酸和脱氢乙酸的含量。样品经提取、脱蛋白、膜过滤后,用高效液相色谱进行测定。结果表明,3种防腐剂的测定线性相关性均在0.99以上,检测线性范围为10μg/mL～200μg/mL。该方法应用于5种月饼中苯甲酸、山梨酸和脱氢乙酸的测定结果表明,5种样品均检出山梨酸,3种样品检出有脱氢乙酸,均未检出苯甲酸。     

高效液相色谱法测定牛奶中3种防腐剂

建立高效液相色谱法测定牛奶中的苯甲酸、山梨酸和脱氢乙酸残留量的方法.样品经体积分数为0.2％乙酸沉淀蛋白,提取过滤后,以乙腈-0.02 mol/L乙酸铵溶液为流动相,经C18反相色谱柱分离,二极管阵列检测器检测.结果表明,苯甲酸和山梨酸的检出限为0.005 mg/g,定量限为0.01 mg/g,脱氢乙酸的检出限为0.0...     

高效液相色谱法检测果蔬汁中五种添加剂

目的:运用高效液色谱法对果蔬汁中苯甲酸、安赛蜜、脱氢乙酸、糖精钠以及山梨酸添加剂进行检测。方法:色谱柱:Kromasil 100-5 C18(250mm×4.6mm,5μg);流动相:甲醇∶0.02mol/L乙酰胺溶液=5∶95(V∶V);流速:1.0m L/min;进样量:20μL;柱温:30℃;波长:230nm。结果:苯甲酸、安赛蜜、脱氢乙酸、糖精钠以及山梨酸在0.00~0.1mg/m L浓度范围内,均表现为良好的线性关系(r=0.97、r=0.98、r=0.96、r=0.98、r=0.98)。山梨酸、安赛蜜、糖精钠、苯甲酸、脱氢乙酸RSD分别为1.13%、1.01%、1.51%、1.05%、1.18%;平均回收率分别为98%~99%。结论:在液果蔬汁添加剂检测中,高效液相色谱法快速准确,且灵敏度较高,可满足检查需要。     

HPLC法测定熟肉制品中苯甲酸、山梨酸和脱氢乙酸的含量

建立HPLC法测定熟肉制品中苯甲酸、山梨酸和脱氢乙酸含量的方法。色谱柱为Thermo Acclaim TM C18(250 mm×4.6 mm,5μm);流动相:甲醇-0.02 mol/L乙酸铵溶液(7:93,v/v);流速:1.0m L/min;检测波长:230 nm;柱温:35℃。结果表明,该方法具有良好的精密度与稳定性,苯甲酸、山梨酸和脱氢乙酸分别在1.17~27.96、1.11~26.63、1.08~25.89μg/m L范围内线性良好,其平均回收率分别为90.4%、94.4%、86.8%。实验结果表明该方法简便、结果准确、重现性好,适用于熟肉制品中苯甲酸、山梨酸及脱氢乙酸的含量测定,为熟肉制品中添加剂的检测奠定了基础。     

超高效液相色谱测定蜂蜜及其制品中的苯甲酸、山梨酸

研究蜂蜜及其制品中的山梨酸与苯甲酸两种防腐剂的提取净化及其超高效液相色谱检测方法。样品用水溶解,超声波辅助提取样品中的山梨酸与苯甲酸。样液经高速离心,滤膜过滤后,采用超高效液相色谱梯度洗脱与二极管阵列检测器测定样品中的山梨酸与苯甲酸的含量。以BEH Shield RP18(2.1mm × 100mm,1.7μm)为色谱柱,以0.02mol/L 乙酸铵溶液和乙醇为流动相梯度洗脱,两种防腐剂在4min 中内实现较好的分离。方法检出限：苯甲酸为2.5mg/kg,山梨酸为2.0mg/kg。以加标样品做添加回收率测定,苯甲酸与山梨酸的回收率分别为94.1%～102.3% 和96.2%～99.8%,相对标准偏差均小于5%。方法简单、快速准确、灵敏度高是一种较好的定性和定量方法。     

花生四烯酸、二十二碳六烯酸和二十碳五烯酸 在炎症中的作用概述

心脑血管疾病、肿瘤、糖尿病、神经系统疾病、自身免疫等疾病严重危害着人类的生命和健康,并消耗着大量医疗资源。事实上,很多疾病发生和发展的背后都伴随着炎症反应,炎症是众多疾病的病理基础,甚至是导致这些疾病的诱因。炎症本身是机体的防御性反应,但过度的炎症反应和长期慢性炎症会损害机体的稳态。炎症的调节和控制由炎症介质介导,花生四烯酸(arachidonic acid,AA)、二十二碳六烯酸(docosahexaenoic acid,DHA)和二十碳五烯酸(eicosapentaenoic acid,EPA)等长链多不饱和脂肪酸(10ng-chain polyunsaturated fatty acids,LC-PUFAs)的衍生物是一类重要的调控炎症的介质。炎性细胞间的交流和细胞内信号传递与LC-PUFAs有关。AA经环氧酶和脂氧合酶合成的类二十烷酸主要起促炎作用,但有的也有抗炎作用。DHA和EPA在体内起抗炎作用,由它们合成的消退素(resolvins,Rvs)和保护素(protectin,PD)是重要的抗炎活性物质。DHA和EPA还可以干扰炎性细胞内信号传导途径来抑制炎症反应。本文从炎症与疾病的关系、LC-PUFAs的衍生物及其促炎和抗炎机制等方面综述了AA、DHA和EPA在炎症中的作用。     

Anti-obesity effects of conjugated linoleic acid, docosahexaenoic acid, and eicosapentaenoic acid

Obesity has become a prevailing epidemic throughout the globe. Effective therapies for obesity become attracting. Food components with beneficial effects on "weight loss" have caught increasing attentions. Conjugated linoleic acid (CLA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) belong to different families of polyunsaturated fatty acids (PUFA). However, they have similar effects on alleviating obesity and/or preventing from obesity. They influence the balance between energy intake and expenditure; and reduce body weight and/or fat deposition in animal models, but show little effect in healthy human subjects. They inhibit key enzymes responsible for lipid synthesis, such as fatty acid synthase and stearoyl-CoA desaturase-1, enhance lipid oxidation and thermogenesis, and prevent free fatty acids from entering adipocytes for lipogenesis. PUFA also exert suppressive effects on several key factors involved in adipocyte differentiation and fat storage. Despite their similar effects and shared mechanisms, they display differences in the regulation of lipid metabolism. Moreover, DHA and EPA exhibit "anti-obesity" effect as well as improving insulin sensitivity, while CLA induces insulin resistance and fatty liver in most cases. A deeper and more detailed investigation into the complex network of anti-obesity regulatory pathways by different PUFA will improve our understanding of the mechanisms of body weight control and reduce the prevalence of obesity.     

酸水解去除谷氨酸母液中的焦谷氨酸

焦谷氨酸没有鲜味,是谷氨酸产品中的无效成分,其安全性尚无定论.控制谷氨酸浓度为16g/100mL、焦谷氨酸的浓度为3.2g/100mL,试验研究了水解温度、硫酸加入量、水解时间等因素对降低谷氨酸母液中焦谷氨酸含量的影响.在保证谷氨酸回收率的基础上,确定出使焦谷氨酸含量达到1.07％及以下的最优水解组合:水解温度(95±5)℃、浓硫酸加入量30％ (v/v)、水解时间2h.在上述试验中,焦谷氨酸的初始含量均为20％.通过改变初始焦谷氨酸氨酸含量20%～35％,最优水解组合下水解后焦谷氨酸含量为0.96％～1.04％,仍可达到1.07％以下.     

气相色谱法同时快速测定食品中丙酸、山梨酸、苯甲酸及脱氢乙酸

通过液液萃取净化样品研究,建立了食品中丙酸、山梨酸、苯甲酸、脱氢乙酸及其盐含量气相色谱同时快速测定方法,适用于固体非酯(脂)类食品的检测。结果表明:丙酸的回收率在85.1%~91.3%之间,其余3种防腐剂的回收率均在95.2%~99.4%之间;实验室内变异系数(CV,n=6)最大值≤4.7%,4种防腐剂检出限均在0.002 g/kg以下。4种目标物在有杂质干扰时,可用不同的极性毛细管柱做进一步的确认。本方法具有适用范围广、检测效率高、重现性好、准确度高、检出限低的特点,推广应用对我国食品安全的监督检验具有重要的意义。     

Short communication: Eicosatrienoic acid and docosatrienoic acid do not promote vaccenic acid accumulation in mixed ruminal cultures

Previous research found that docosahexaenoic acid (C22:6n-3) was a component of fish oil that promotes trans-C18:1 accumulation in ruminal cultures when incubated with linoleic acid. The objective of this study was to determine if eicosatrienoic acid (C20:3n-3) and docosatrienoic acid (C22:3n-3), n-3 fatty acids in fish oil, promote accumulation of trans-C18:1, vaccenic acid (VA) in particular, using cultures of mixed ruminal microorganisms. Treatments consisted of control, control plus 5 mg of C20:3n-3 (ETA), control plus 5 mg of C22:3n-3 (DTA), control plus 15 mg of linoleic acid (LA), control plus 5 mg of C20:3n-3 and 15 mg of linoleic acid (ETALA), and control plus 5 mg of C22:3n-3 and 15 mg of linoleic acid (DTALA). Treatments were incubated in triplicate in 125-mL flasks, and 5 mL of culture contents was taken at 0 and 24 h for fatty acid analysis by gas-liquid chromatography. After 24 h of incubation, the concentrations of trans-C18:1 (0.87, 0.88, and 0.99 mg/culture), and VA (0.52, 0.56, and 0.62 mg/culture) were similar for the control, ETA, and DTA cultures, respectively. The concentrations of trans-C18:1 (5.51, 5.41, and 5.36 mg/culture), and VA (4.78, 4.62, and 4.59 mg/culture) were also similar between LA, ETALA, and DTALA cultures, respectively. These data suggest that C20:3n-3 and C22:3n-3 are not the active components in fish oil that promote VA accumulation when incubated with linoleic acid.     

杂多酸催化合成辛酸蔗糖酯

以蔗糖、辛酸为原料,杂多酸为催化剂合成辛酸蔗糖酯。用L16(45)正交设计优化实验,高效液相色谱法分析反应液组成。考察了催化剂种类和用量、反应温度、原料配比、反应时间等因素对辛酸蔗糖酯产率的影响,发现以二甲基亚砜为溶剂、蔗糖与辛酸摩尔比1∶9、磷钨酸用量为蔗糖质量的2.0%、110℃反应时间6h,蔗糖转化率达60%,产物产要是二酯。动力学研究发现,蔗糖反应级数为一级,反应表观速率常数为0.0059min-1(90℃)、0.0117min-1(110℃),反应表观活化能Ea=39.57kJ/mol。     

生活饮用水中乙二胺四乙酸和次氮基三乙酸含量测定

目的：建立一种生活饮用水中乙二胺四乙酸（EDTA）和次氮基三乙酸（NTA）的高效液相色谱测定方法。方法：样品与三氯化铁络合后,以甲醇和0.2 mmol/L四丁基溴化铵—磷酸缓冲溶液（pH 2.5）为流动相,梯度洗脱后经Thermo-C₁₈（4.6 mm×250 mm）色谱柱分离,DAD检测器检测,外标法定量。结果：EDTA和NTA在0.1～2.0 mg/L质量浓度范围内与色谱峰面积线性关系良好,相关系数分别为0.999 5,0.999 2;两者的检出限为0.05 mg/L,定量限为0.1 mg/L,平均加标回收率为93.5%～111.4%,相对标准偏差（RSD）为3.63%～7.39%。结论：该方法操作简便,重复性好,灵敏度高,具有较好的实用性。     

气相色谱法测定鱼油中的二十碳五烯酸、 二十二碳六烯酸和二十二碳五烯酸

目的通过优化鱼油中二十碳五烯酸(eicosapentaenoic acid,EPA)、二十二碳六烯酸(docosahexaenoic acid,DHA)和二十二碳五烯酸(docosapentaenoic acid,DPA)的测定条件,建立鱼油中EPA、DHA和DPA气相色谱定量检测分析方法。方法采用正己烷处理样品,经色谱柱(Agilent,Elite-WAX,30 m×0.25 mm,0.25μm)分离鱼油中的EPA、DHA、DPA甲酯标准品,并进行定量检测。结果 EPA浓度在0.36~3.6 mg/m L、DHA浓度在0.37~3.7 mg/m L、DPA浓度在0.16~1.62 mg/m L的范围内与峰面积的线性良好,相关系数r0.999。在80%、100%、120%添加水平下,EPA、DHA和DPA的检出限分别为0.01%、0.03%、0.009%,EPA、DHA和DPA的回收率分别为96.2%、96.4%、95.7%。结论气相色谱法灵敏度高、准确、重现性好,适用于鱼油中EPA、DHA和DPA的含量测定。     

高效液相色谱法检测贝类中的乳酸和琥珀酸

研究探讨利用高效液相色谱测定贝类中乳酸和琥珀酸的样品处理方法和测定方法,结果显示:与乙醇沉淀法、国标法相比,流动相提取法更适合作为样品的提取方法,在检测条件中,流动相为pH2.5的2.0%NH4H2PO4,流速在1.0mL/min,波长为205nm为最优条件。此方法具有较好的线性、较高的准确度和精密度,加标实验回收率为94.0%～99.9%,相对标准偏差为0.09%～0.14%。也测定了两种贝类中乳酸和琥珀酸的含量。     

Short communication: docosahexaenoic acid promotes vaccenic acid accumulation in mixed ruminal cultures when incubated with linoleic acid

Previous studies found that feeding dairy cows a blend of fish and soybean oils enhanced milk vaccenic acid (VA) and conjugated linoleic acid (CLA) concentrations more than when the oils were fed separately. In these studies, the authors concluded that a component in fish oil was stimulating ruminal VA production from other sources of unsaturated fatty acids; however, that component was not identified. The objective of this study was to determine whether docosahexaenoic acid (DHA), an omega-3 fatty acid (FA) in fish oil, is the active component that promotes trans-C18:1 FA, VA in particular, accumulation using cultures of mixed ruminal microorganisms. Treatments consisted of control, control plus 5 mg of DHA (DH), control plus 30 mg of soybean oil (SBO), and control plus 5 mg of DHA and 30 mg of SBO (DHSBO). Treatments were incubated in triplicate in 125-mL flasks, and 5 mL of culture contents was taken at 0 and 24 h for fatty acid analysis by gas-liquid chromatography. After 24 h of incubation, the level of trans-C18:1 FA (14.1 and 11.7 mg/culture) and VA (13.0 and 10.2 mg/culture) increased more with added DHA than with added SBO, respectively. Combining DHA and SBO yielded higher quantities of trans-C18:1 FA (21.3 mg/culture) and VA (19.8 mg/culture) in the cultures than either fat source alone. These data suggest that DHA is the component in fish oil that promotes VA accumulation when incubated with linoleic acid.