Determination method of polysorbates in powdered soup by HPLC

A method for qualitative and quantitative analyses of polysorbates in powdered soup by HPLC was studied. Polysorbates in samples were extracted with acetonitrile after rinsing with n-hexane to remove fats and oils. The extract was cleaned up using a Bond Elut silica gel cartridge (500 mg). The cartridge was washed with ethyl acetate and polysorbates were eluted with a small amount of acetonitrile-methanol (1:2) mixture. The eluate was treated with cobalt thiocyanate solution to form a blue complex with polysorbate. In order to determine polysorbate, the complex was subjected to HPLC with a GPC column, using a mixture of acetonitrile-water (95:5) as a mobile phase, with a detection wavelength of 620 nm. The recoveries of polysorbate 80 added to powdered soups were more than 75% and the determination limit was 0.04 mg/g. When the proposed method was applied to the determination of polysorbates in 16 commercial samples of powdered soup for instant noodles and seasoning consomme, no polysorbates were detected in any sample.     

Metabolites of Eurotium Species, Their Antioxidative Properties and Synergism with Tocopherol

Natural antioxidants and synergists for tocopherol (Toc) have been isolated as acetone or ethyl acetate extracts from mycelial mats or culture broth of Eurotium species. The acetone extract, eluted stepwise with benzene and ethyl acetate by silica gel column chromatography, gave fractions that were synergistic with Toe. However, the benzene fraction appeared better because it was highly soluble in oil and did not change the color and taste of the oil. The metabolites in the benzene fraction differed in the various Eurotium species in their composition in respect to known metabolites with antioxidative activity.     

杂色曲菌素HPLC 检测方法的建立及其在大米污染样品中的运用

采用自制杂色曲菌素(VA)标准品,建立大米中杂色曲菌素的高效液相色谱检测方法。大米污染样品经丙酮提取、柱色谱净化,HPLC- 紫外检测器进行测定,检测波长288nm。结果表明,VA 在100～1250ng/mL 质量浓度范围内线性关系良好,r ＞ 0.999,方法回收率在84.12%～105.12% 之间,平均变异系数小于7.5%,最低检测限为50ng/mL。该方法灵敏度较高、稳定性好、成本较低,可以用于粮食中杂色曲菌素的定量检测。     

辣椒中β-隐黄质的分离制备

建立从辣椒中分离制备高纯度β-隐黄质的方法。辣椒粉先经丙酮超声提取、皂化,硅胶柱色谱进行粗分后进一步采用制备液相对β-隐黄质分离制备。通过紫外光、电喷雾电离质谱、核磁共振氢谱和核磁共振碳谱对所分离的β-隐黄质进行结构鉴定,分析型高效液相色谱进行纯度测定。结果表明：每5g辣椒色素浸膏与异丙醇的比例为1:9(g/mL)、加入6.5mL质量浓度为20g/100mL的KOH-甲醇溶液,在室温条件下皂化24h,皂化完全;硅胶柱色谱进行粗分时用石油醚与丙酮作为洗脱溶剂,当体积比为10:1时,β-隐黄质得到较好的富集;制备液相的条件为丙酮-水(95:5,V/V)、流速5mL/min,可制备分离出纯度为99.0%的β-隐黄质单体。该方法简便快捷、重现性好、所得β-隐黄质纯度高,可作为β-隐黄质的分离制备研究。     

番石榴叶乙酸乙酯萃取物的体外抗氧化活性及化学成分的分离鉴定

本文研究了番石榴叶乙酸乙酯萃取物的体外抗氧化活性及活性物质基础。采用95%乙醇溶液浸泡提取、正己烷和乙酸乙酯萃取后得到粗提物,首先分析了乙酸乙酯萃取物的体外抗氧化活性,然后通过硅胶柱色谱、Sephadex LH-20凝胶柱色谱、质谱和核磁共振等技术对乙酸乙酯萃取物的化学成分进行了分离和鉴定。结果表明,乙酸乙酯萃取物对DPPH自由基、超氧阴离子、羟自由基具有较强的体外抗氧化活性,清除能力随着浓度的增大而增强,当浓度为1 mg/m L时,对DPPH自由基、超氧阴离子和羟自由基的清除率分别达94.15%、87.88%和67.3%,清除效果接近或强于同浓度的Vc。通过硅胶柱色普、Sephadex LH-20凝胶柱色谱等技术从番石榴叶乙酸乙酯萃取部位中分离纯化得到5个化合物,通过MS和NMR等波谱数据和结合文献,最终确定了4个化合物,分别为:去甲氧基荚果蕨(1)、胶藤素(2)、槲皮素(3)和异槲皮苷(4),其中化合物2为首次从番石榴属植物中分离得到的二氢黄酮类化合物。     

硅胶柱层析分离啤酒花中的黄腐酚

利用硅胶柱层析法对啤酒花浸膏中的黄腐酚进行了分离,采取了2种洗脱方法。方法一是采用石油醚和乙酸乙酯固定比例(2:1)洗脱2次,第1次洗脱后合并含有黄腐酚的洗脱液,浓缩成浸膏,进行第2次洗脱;方法二是以石油醚和乙酸乙酯的混合溶剂梯度洗脱2次,第1次梯度洗脱后合并含有黄腐酚的洗脱液,浓缩成浸膏,进行第2次梯度洗脱。结果表明,方法一的分离效率高、速度快,黄腐酚得率较高(44.88%),但黄腐酚的纯度较低(57.78%);方法二的黄腐酚得率较低(43.16%),但纯度高(81.10%),部分馏分浓缩后有结晶析出,经HPLC检测为黄腐酚结晶单体,纯度达到98.1%,因此可以应用硅胶柱层析法高效分离和纯化啤酒花黄腐酚。     

免疫亲和柱-高效液相色谱法检测乳制品中氯霉素

建立免疫亲和柱富集净化、高效液相色谱-紫外法快速测定牛奶和奶粉中氯霉素残留物。样品用乙酸乙酯提取,经免疫亲和色谱柱纯化,应用液相色谱-紫外法检测。结果表明,牛奶和奶粉添加氯霉素,回收率为79.6%~108.6%,变异系数小于10%;方法检测灵敏度0.1μg/L。该方法能够特异性的纯化牛奶和奶粉样品中的氯霉素,免疫亲和柱(IAC)净化是一种简单,快速,准确的方法。     

甘蓝中氟啶脲残留量测定方法的研究

建立氟啶脲在甘蓝中的残留分析方法。样品用乙酸乙酯提取,弗罗里硅土柱净化,高效液相色谱法测定。结果表明：本方法最小检出量为1.2ng,在0.05、0.5、2mg/kg 添加水平下,添加回收率在81.95%～100% 范围内,变异系数范围为2.37%～6.21%。该方法符合农药残留分析的要求,适于甘蓝中氟啶脲的检测。     

二十二碳六烯酸海藻糖酯的分离纯化及鉴定

在叔丁醇中以二十二碳六烯酸(DHA)乙酯和海藻糖为原料,通过固定化脂肪酶催化合成DHA海藻糖酯,并对其分离纯化方法进行研究。确定DHA海藻糖酯的薄层层析(TLC)条件:展开剂为乙酸乙酯/甲醇/水(8.5/1/0.5,v/v/v),碘蒸气显色10min;硅胶柱层析条件:正己烷/异丙醇/甲醇(5/4/1和4/4/2,v/v/v)梯度洗脱,流速1.3mL/min,1管/7min收集洗出液;用半制备高效液相色谱(HPLC)进一步纯化单酯收集液,经分析型HPLC检测纯度后用核磁共振(NMR)方法进行结构鉴定,确定为DHA藻糖单酯。     

海参中脑苷脂类物质的分离纯化研究

目的：对海参中生物活性物质脑苷脂的提取分离条件进行初步尝试和探讨;方法：氯仿- 甲醇提取,石油醚和乙酸乙酯初步分离,硅胶柱层析进一步分离,高效液相色谱纯化,GC-MS 进行结构鉴定;结果：从海参中成功提取并纯化出天然化合物,经结构鉴定后认定为脑苷脂类化合物。     

Comparison of sulfuric acid treatment and multi-layer silica gel column chromatography in cleanup methods for determination of PCDDs,PCDFs and dioxin-like PCBs in foods

Two typical cleanup methods, sulfuric acid treatment and multi-layer silica gel column chromatography, for the determination of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dioxin-like PCBs) in seventeen food samples were examined and compared. Vegetables, fruits, cereals, fish, meat and dairy foods were extracted by conventional methods (shaking with acetone/n-hexane or with n-hexane after alkaline treatment). The extracts were cleaned up by sulfuric acid treatment or multi-layer silica gel column chromatography, followed by several column chromatographic steps. Of the samples treated, the vegetable, fruit and cereal samples could be directly applied to the multi-layer silica gel column after extraction. However, the samples containing fats and oils such as fish, meat and dairy foods needed to be treated several times with concentrated sulfuric acid before multi-layer column chromatography, because these samples plugged the column with oily residues. Both cleanup methods gave similar values of isomeric concentrations and showed similar efficiency of purification, and the recoveries ranged from 40 to 120%. These results are considered to provide useful data for the efficient analysis of dioxins in foods which have wide-ranging compositions.     

Clean-up method of forchlorfenuron in agricultural products for HPLC analysis

A simplified method for the determination of forchlorfenuron in agricultural products by HPLC with UV detection was investigated. A chopped sample homogenate from agricultural products was extracted with acetone. The extract was filtrated and concentrated. The residues was loaded onto a Chem Elut column and extracted with ethyl acetate. The crude extract was purified on Oasis HLB and Bond Elut PSA mini-columns using a mixture of methanol and ethyl acetate. Forchlorfenuron was analyzed by HPLC with UV detection (263 nm). HPLC separation was performed on an ODS column with methanol-water as the mobile phase. Recoveries of forchlorfenuron from several agricultural products fortified at the level of 0.1 microg/g were in the range of 87.6-99.5%. The limit of detection (S/N=3) was 0.005 microg/g in the sample.     

猴头菇醇提物乙酸乙酯萃取相组分的分离与鉴定

研究了猴头菇中具有较好抗氧化特性的醇提物乙酸乙酯萃取相的化学成分。采用硅胶柱层析以及半制备HPLC法对猴头菇醇提物的乙酸乙酯萃取相进行分离纯化,将纯化得到的单体化合物进行结构表征和鉴定。结果表明,分离鉴定得到5个明确的化合物,分别为油酸(Oleic acid,化合物H1)、正二十九烷(n-Nonacosane,化合物H3)、尿苷(Uridine,化合物H4)、以及属于异苯并呋喃酮衍生物的猴头菇子实体次生代谢产物Hericenone I(化合物H2)和Hericenone J(化合物H5)。     

Simultaneous determination of N-methylcarbamates and their metabolites in citrus fruits by HPLC avoiding use of halogenic solvents

Twenty-one N-methylcarbamates (NMCs) and 12 of their metabolites or isomers in citrus fruits were simultaneously determined avoiding use of dichloromethane. NMCs in lemon, orange, and grapefruit were extracted with acetone, then the acetone was evaporated off and sodium chloride was added before extraction with ethyl acetate. The extract was evaporated and the residue was cleaned up on a combined mini-column set of Supelclean ENVI-Carb and Mega Bond Elut SAX cartridges. NMCs were determined by HPLC with post-column reaction and fluorescence detection. All of the NMCs in the orange sample were determined without interfering peaks. However 8 NMCs in lemon extract and 10 NMCs in grapefruit extract were not detected because interfering peaks appeared at similar retention times to those of the NMCs. These NMCs were determined using LC/MS (SIM) and were well recovered. Eighty-three data sets obtained by HPLC and LC/MS showed good similarity, with r2 = 0.9178. Recoveries were 60.1 to 97.8% for major NMCs at a fortification level of 0.1 ppm. The limit of detection by HPLC was 0.005 ppm NMCs in samples and a similar level applied to LC/MS.     

免疫亲和柱——高效液相色谱法测定肾脏中的赭曲霉毒素A

目的针对动物肾脏中可能污染的赭曲霉毒素A(OTA),建立了肾脏中赭曲霉毒素A的高效液相色谱方法。方法试样用磷酸酸化后经乙酸乙酯提取,免疫亲和柱净化,以乙腈-水-冰醋酸(450+525+25)为流动相,C18柱分离并通过荧光检测器定量。结果赭曲霉毒素A标准溶液浓度在0.10～20μg/L范围内呈线性相关(r=1.000 0),不同浓度水平的添加回收率为72.5%～87.4%,检出限为0.012μg/kg。结论使用免疫亲和柱净化能够达到良好的净化效果,是一种准确、方便的测定猪肾中赭曲霉毒素A的分析方法。     

栀子黄色素标准品藏红花素的制备

用栀子果实为原料,采用大孔吸附树脂法联合硅胶层析法精制栀子黄色素的标准品藏红花素。其栀子黄色素树脂精制条件:吸附条件为树脂30 mL,栀子黄色素提取液上样量300 mL;吸附流速1.5 mL/min;洗脱条件为提取液杂质洗脱乙醇体积分数30%,洗脱体积150 mL;栀子黄色素洗脱乙醇体积分数50%,洗脱体积150 mL;在此条件下可制得色价≥300,OD值0.4的桅子黄色素,并用其硅胶层析精制藏红花素。硅胶柱层析条件,洗脱流动相:V(乙酸乙酯)∶V(甲醇)∶V(水)=10∶2∶1;V(乙酸乙酯)∶V(甲醇)∶V(水)=10∶3∶1,进行梯度洗脱制取藏红花素。栀子黄色素提取液经过分离纯化,红外光谱、质谱测定,确定为藏红花素的结构,经高效液相色谱检测,藏红花素的纯度达98%。     

植物油中角鲨烯的提取与高效液相色谱法分析

建立了硅胶柱提取,高效液相色谱法分析植物油中角鲨烯的方法.样品用石油醚溶解,过硅胶柱净化,经C18柱分离,紫外检测(210 nm).结果表明,角鲨烯与其他杂质峰得到良好分离,在2～1 000 mg/L浓度范围内,峰面积与浓度呈良好线性,线性相关系数(R2)0.998.在大豆油中添加5.0、100、500和1 000mg/kg水平的角鲨烯,平均加标回收率为82.4％～ 89.3％,相对标准偏差小于7.1％(n=8),方法测定低限(LOQ)5 mg/kg.本方法准确、灵敏、可靠,已应用于实际样品分析.     

小曲酒酿造废水中高粱红色素的分离纯化工艺研究

用大孔树脂耦合硅胶柱层析法对小曲酒酿造废水中的高粱红色素进行分离纯化,通过单因素试验,确定了大孔树脂和硅胶 层析柱的纯化条件。 结果表明,一级纯化选择HPD600型大孔树脂,吸附容量为2 BV,吸附液pH值为7,吸附速率为3 BV/h,除杂水用 量为5 BV,洗脱剂为体积分数80%的乙醇,洗脱剂用量为2 BV,洗脱速率为6 BV/h;二级纯化用硅胶层析柱,流动相为石油醚∶乙酸 乙酯=4∶1（V/V）,目标收集液为2～3 BV段的流动相收集液;经两级纯化后得到高粱红色素纯度达90%,废水中高粱红色素的回收率 达67.2%。     

液相色谱- 串联质谱法测定海产品中21 种磺胺类药物残留

研究一种能够同时测定水产品中21 种磺胺类药物残留量的检测方法--超高效液相色谱质谱法。样品经乙酸乙酯提取,经固相萃取小柱净化,氮气吹干后,用1mL 流动相定容残余物。采用ACQUITYTM BEH C18 色谱柱,用甲醇和5mmol/L 乙酸铵溶液(含体积分数0.1% 甲酸)作流动相,采用质谱技术分析。结果表明,检出限为0.01～0.20μg/kg,定量限为0.03～0.67μg/kg,平均回收率为68%～82%,相对标准偏差为4.1%～11.8%。该方法适合水产品中多种磺胺类药物的检测。     

Methods to purify and determine rubratoxins

Rubratoxin were recovered from cultures of Penicillium rubrum after the mold grew in natural substrates, a semi-synthetic medium, and a glucosemineral salts broth. Substrates that contained rubratoxins were extracted with: diethyl ether, ethyl acetate-benzene, ethanol (100%), ethanol-acetone, acetonitrile, or diethyl ether with refluxing at 45 degrees C. Extracts were screened for rubratoxins by thin-layer chromatography. Some extracts were partially purified with a column of silicic acid using acetone as the eluant. Other extracts were purified (primarily removal of pigments) using columns of silica gel plus Celite and gradient solvent elution. Most rubratoxin B (1.9 mg/g or 0.77 mg/ml) was recovered when corn, rice, or glucose-salts broth were extracted successively with diethyl ether, ethyl acetate-benzene, and diethyl ether or when samples were adjusted to pH 1.5 before refluxing with diethyl ether at 45 degrees C for 1--4h. Most rubratoxin A (0.1--0.15 mg/ml or 1.0 mg/g) was obtained from samples of corn extracted twice each with ethyl alcohol, acetone, and ethyl acetate; from glucose-mineral salts broth extracted with diethyl ether; or from yeast extract sucrose broth extracted with diethyl ether and refluxed for 4 h at 45 degrees C. Large amounts of fairly pure rubratoxin A (up to 400 mg) and rubratoxin B (greater than lg) were obtained with a combination of preparative thin-layer and column chromatography.