高效液相色谱法检测运动饮料中双酚A的残留

建立一种快速、有效的高效液相色谱法测定运动饮料中双酚A残留的方法。样品经乙醇提取后,采用C18固相萃取小柱进行净化和富集。采用苯基色谱柱(4.6 mm×250 mm,5μm)分离,以乙腈∶水=40∶60(体积比)作为流动相,用PDA检测器检测,外标法峰面积定量。结果表明,双酚A标液在0.10μg/m L~1.00μg/m L浓度范围内线性良好,相关系数r~2为0.999,检出限为5.0μg/kg,定量限为15.0μg/kg,加标回收率达到92.1%~93.8%。该方法具有前处理简单、富集效果好和检测速度快的优点,适用于运动饮料中双酚A残留的定量检测。     

高效液相色谱法检测运动饮料中的L-肉碱

建立一种快速、有效的高效液相色谱法测定运动饮料中L-肉碱的方法。样品经1.0 mmol/L盐酸提取后,采用MCX固相萃取小柱进行净化和富集。采用RP C18柱(4.6 mm×250 mm,5μm)分离,以乙腈∶辛烷磺酸钠(50 mmol/L)=25∶75(体积比)作为流动相,用PDA检测器检测,外标法峰面积定量。结果表明,L-肉碱标液在1.0μg/m L~20.0μg/m L浓度范围内线性良好,相关系数r~2为0.999,检出限为0.1 mg/kg,定量限为0.3 mg/kg,加标回收率达到82.3%~84.1%。     

高效液相色谱法检测乳品饮料中四环素类抗生素

建立一种用固相萃取-高效液相色谱法测定乳品饮料中土霉素、四环素、金霉素、强力霉素的检测方法。样品前处理用乙腈沉淀蛋白后,采用HLB固相萃取小柱进行净化和富集,氮气吹干后用流动相复溶上机检测。采用Waters RP C18色谱柱(4.6 mm×250 mm,5μm)分离,以乙腈∶甲醇∶0.01mol/L草酸溶液(18∶5∶77)作为流动相,用PDA检测器检测,外标法峰面积定量。结果表明,4种四环素类抗生素在0.10μg/m L~1.00μg/m L浓度范围内线性良好,相关系数r2为0.994~0.999,检出限均为2.0μg/kg~5.0μg/kg,定量限均为6.0μg/kg~15.0μg/kg,加标回收率达到77.6%~90.6%。     

HPLC-UV-FL串联法测定染色废水中的苯胺

利用固相萃取-高效液相色谱紫外荧光串联建立了染色废水中苯胺的检测方法。样品经MCX固相萃取小柱提取、净化后,采用Kromasil C18柱(250 mm×4.6 mm,内径5μm)分离,水/乙腈(20/80,体积比)为流动相,紫外检测波长为235 nm,荧光检测波长:λex为225 nm,λem为335 nm,外标法定量。试验结果显示,荧光检测条件下,苯胺在0.001~0.500 mg/L范围内呈良好的线性关系,最低检出限LOD为0.001 mg/L,定量检出限LOQ为0.003 mg/L。紫外检测条件下,苯胺在0.02~5.00 mg/L范围内呈良好的线性关系,最低检出限LOD为0.02 mg/L,定量检出限LOQ为0.06 mg/L,方法回收率在95.6%~101.8%,RSD为2.2%~5.2%,能满足测定要求。     

高效液相色谱法检测运动饮料中甜菊糖苷

建立一种用高效液相色谱-PDA检测法测定运动饮料中甜菊糖苷的检测方法。样品前处理采用硅胶固相萃取小柱进行富集和净化,氮气吹干后用流动相复溶上机检测。采用Waters RP C18色谱柱(4.6 mm×250 mm,5μm)分离,以乙腈∶水=30∶70(体积比)作为流动相,用PDA检测器检测,外标法峰面积定量。结果表明,9种甜菊糖苷组分在20.0μg/m L~200.00μg/m L浓度范围内线性良好,相关系数r2为0.991~0.999,检出限在1.0μg/m L~3.0μg/m L,定量限为3.0μg/m L~9.0μg/m L,加标回收率达到81.4%~90.5%。     

甜茶中齐墩果酸及熊果酸的检测方法的建立

建立测定甜茶中齐墩果酸及熊果酸的高效液相色谱分析方法。对色谱分析条件及样品前处理进行优化研究,样品经乙醇超声波提取,醇提水沉进行杂质沉淀,以Hypersil Gold C_(18)(250 mm×4.6 mm,5μm)为分析柱,甲醇和0.2%乙酸铵溶液(83∶17)为流动相,检测波长为210 nm,流速为0.6 m L/min,外标法进行定量。在此条件下,齐墩果酸及熊果酸能达到完全基线分离,分别在2.23μg/m L~112μg/m L、1.84μg/m L~92μg/m L浓度范围内具有良好的线性关系(R~20.999),方法检出限分别为0.04、0.08 g/kg。在低中高3种含量添加水平的回收率在92%~102%,RSD(n=6)为0.8%~3.8%。     

UPLC-MS/MS检测果蔬饮料中痕量吡虫啉

建立一种快速、有效的超高效液相色谱-串联质谱法测定果蔬饮料中痕量吡虫啉农药残留的方法。样品经0.1%醋酸-乙腈提取后,采用氨基固相萃取小柱进行净化和富集。采用Waters Atalantis T3色谱柱(2.1 mm×150 mm,3μm)分离,以0.1%甲酸-乙腈为流动相的梯度洗脱模式下,吡虫啉标准在0.5 ng/mL~50.0 ng/mL浓度范围内线性良好,相关系数r~2为0.999,检出限为0.15μg/kg,定量限为0.50μg/kg,加标回收率达到93.2%~96.9%。     

基于固相萃取-高效液相色谱法的纺织品中三氯生的测定

建立了纺织品中三氯生的固相萃取-高效液相色谱检测方法。样品经超声提取后,用固相萃取进行净化,Kromasil C18 柱（250 mm × 4.6 mm i.d., 5 μm）分离,采用水/乙腈 (15/85, V/V)为流动相,紫外检测波长为280 nm,外标法定量。实验结果显示：样品中的三氯生在0.1~20.0 mg/kg的浓度范围内呈良好的线性关系,最低检出限LOD为0.01mg/kg,定量检出限LOQ为0.05 mg/kg 。方法回收率在94.0%~100.4%之间,RSD 为2.0%~4.4% 。本方法简便、快速、专属性强、干扰少,能满足纺织品中三氯生的测定要求。     

RP-HPLC法测定新疆6种红枣中齐墩果酸和熊果酸的含量

采用反相高效液相色谱法测定新疆不同品种红枣中齐墩果酸和熊果酸的含量。采用Kromasil C18柱(4.6 mm×250 mm,5μm),流动相为甲醇-0.03 mol/L的磷酸二氢钠(磷酸调pH至3.0)(90:10),流速为0.8 mL/min,检测波长为210 nm,柱温25℃。上述色谱条件下红枣中齐墩果酸、熊果酸可完全分离,线性范围分别为齐墩果酸0.4～ 2.0μg(r=0.9998),熊果酸0.448～ 2.24μg(r=0.9999);平均回收率分别为齐墩果酸99.4%,RSD=1.33%,熊果酸99.6%,RSD=1.43%(n=6)。该方法快速、准确、可靠,可用于红枣中齐墩果酸和熊果酸含量的同时测定。     

高效液相色谱检测运动饮料中的人工合成色素

建立一种同时测定运动饮料中柠檬黄、苋菜红、胭脂红、日落黄、诱惑红、亮蓝等6种人工合成色素的固相萃取-高效液相色谱(SPE-HPLC)方法。样品前处理采用固相萃取小柱进行富集和净化,淋洗液选择甲酸-水溶液,洗脱液选择氨化甲醇,氮气吹干后用水复溶上机检测。采用Waters RP C_(18)色谱柱(4.6 mm×250 mm,5μm)分离,以甲醇-乙酸铵水溶液(20.0 mmol/L)作为流动相,用PDA检测器检测,外标法峰面积定量。结果表明,6种人工合成色素在2.00μg/m L~32.00μg/m L浓度范围内线性良好,相关系数r2为0.99,检出限在0.04μg/m L~0.15μg/m L,定量限为0.12μg/m L~0.50μg/m L,加标回收率达到85.6%~92.4%。该方法具有前处理简单、净化效果好、灵敏度高和检测速度快的优点,适用于运动饮料中人工合成色素的分离和定量检测。     

Photostabilization of ascorbic acid with citric acid, tartaric acid and boric acid in cream formulations

This study involves the evaluation of the effect of certain stabilizers, that is, citric acid (CT), tartaric acid (TA) and boric acid (BA) on the degradation of ascorbic acid (AH(2) ) in oil-in-water cream formulations exposed to the UV light and stored in the dark. The apparent first-order rate constants (0.34-0.95 × 10(-3) min(-1) in light, 0.38-1.24 × 10(-2) day(-1) in dark) for the degradation reactions in the presence of the stabilizers have been determined. These rate constants have been used to derive the second-order rate constants (0.26-1.45 × 10(-2) M(-1) min(-1) in light, 3.75-8.50 × 10(-3) M(-1) day(-1) in dark) for the interaction of AH(2) and the individual stabilizers. These stabilizers are effective in causing the inhibition of the rate of degradation of AH(2) both in the light and in the dark. The inhibitory effect of the stabilizers is in the order of CT > TA > BA. The rate of degradation of AH(2) in the presence of these stabilizers in the light is about 120 times higher than that in the dark. This could be explained on the basis of the deactivation of AH(2) -excited triplet state by CT and TA and by the inhibition of AH(2) degradation through complex formation with BA. AH(2) leads to the formation of dehydroascorbic acid (A) by chemical and photooxidation in cream formulations.     

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。     

Antioxidant and pro-oxidant properties of ascorbic acid and gallic acid

The antioxidant and pro-oxidant properties of ascorbic acid (AA) and gallic acid (GA) were investigated. AA and GA, at a concentration of 1.65 mM, accelerate the oxidation of deoxyribose induced by Fe³⁺–EDTAJH₂O₂. The reducing power of these two compounds increased upon increasing the concentration. AA and GA showed no chelating ability toward iron (II). At a concentration of 4.17 mM, AA and GA exhibited 42.1 and 43.9% scavenging effects on DPPH radicals, respectively. They exhibited 60% scavenging effects on hydrogen peroxide at a concentration of 4.17 mM. No toxicity was found in AA and GA toward human lymphocytes. AA, at 0.82 mM, and GA, at 0.6 mM, exhibited the maximal DNA damage, the means of tail DNA% were 14.8 and 28.8%, respectively. When AA and GA were mixed with H₂O₂, they exhibited a slight inhibitory effect on DNA damage induced by H₂O₂ on pre-incubating both the compounds with human lymphocytes for 30 min before exposure to H₂O₂. The antioxidant activities of AA and GA at a higher concentration were mainly due to the scavenging of hydrogen peroxide in this system. The pro-oxidant mechanism for AA and GA acid is most likely due to the strong reducing power and weak metalchelating ability.     

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。     

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.     

氧化铝-硫酸固体酸催化剂催化油酸与甲醇酯化反应及其动力学研究

以氯仿为溶剂,通过氧化铝和氯磺酸反应制备了氧化铝-硫酸(ASA)固体酸催化剂,以油酸转化率为指标,考察了ASA催化剂在油酸与甲醇酯化反应中反应时间、醇酸摩尔比、催化剂用量及氯磺酸负载量对酯化反应的影响。得到的最佳酯化反应条件为:氯磺酸负载量4.1 mmol/g,反应时间6 h,反应温度68℃,醇酸摩尔比8∶1,催化剂用量为油酸质量的5%。在最佳酯化反应条件下,油酸转化率达到93.1%,ASA催化剂重复使用5次,油酸转化率仍在80%以上。在303~333K范围内,油酸和甲醇的酯化反应符合准二级动力学方程,表观活化能为54.34 kJ/mol,指前因子为2.91×109L/(mol·h)。     

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。     

油酸乙氧基化物与硬脂酸乙氧基化物的合成与性能

以油酸和硬脂酸为原料,与环氧乙烷(EO)反应得到平均EO加合数为15的油酸乙氧基化物(OAE-15)和硬脂酸乙氧基化物(SAE-15)。通过FT-IR以及化学方法确定了生成物的结构。对OAE-15和SAE-15的物化性能和应用性能进行了测试并进行了对比,结果表明:SAE-15的去污性能优于OAE-15,降低表面张力的能力和效率都高于OAE-15,二者泡沫性能相当;OAE-15的润湿性能和乳化性能都优于SAE-15。     

Malic acid and oxalic acid spraying enhances phytic acid degradation and total antioxidant capacity of mung bean sprouts

In this study, effects of two organic acids spraying on the growth profiles, phytic acid content, antioxidant capacity, phytase activity and related genes expression during mung bean germination were investigated. Results showed that both oxalic acid and malic acid spraying were effective ways to improve the degradation of phytic acid by inducing phytase activity and the related genes expression, but no significant difference was found in phytic acid content between the two treatments. The contents of total phenolics and MDA (malondialdehyde) in oxalic acid spraying were higher, whereas ascorbic acid content and sprout length in malic acid spraying was higher. Both organic acid treatments could increase antioxidant capacities, but higher antioxidant capacities were found in oxalic acid spraying due to higher total phenolics content and antioxidant enzyme activity.     

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。