基质固相分散萃取-超高效液相色谱串联质谱法检测大米中27种农药残留量

目的建立基质固相分散萃取-超高效液相色谱-串联质谱法(matrixsolidphasedispersive extraction-ultra performance liquid chromatography-tandem mass spectrometry, MSPD-UPLC-MS/MS)检测大米中27种农药残留的分析方法。方法以中性氧化铝为吸附剂, C18为固相萃取净化剂,以甲醇-二氯甲烷(2:1, V:V)为洗脱溶剂,提取液经UPLC-MS/MS分析。结果 27种化合物线性关系良好,相关系数均大于0.999,方法检出限为0.2～4.0μg/kg,定量限为0.4～10.0μg/kg;加标回收率为76.7%～113.3%,相对标准偏差为1.7%～13.7%。结论该方法灵敏、准确,适合于大米样品中27种农药残留的定性和定量检测。     

固相萃取-超高效液相色谱串联质谱法测定母乳中的游离态双酚A

目的 建立了超高效液相色谱-串联三重四级杆质谱(UPLC-MS/MS)测定母乳中游离态双酚A(BPA)的方法.方法 BPA经甲醇-丙酮(1∶1,V/V)超声提取后,过固相萃取柱(Waters Sep-Pak NH26 cc)进行净化,甲醇-丙酮(1∶1,V/V)洗脱,经Waters ACQUITY BEH C18色谱柱(50 mm×2.1mm×1.7μm)分离,在电喷雾负离子源和多反应监测模式下进行测定,内标法定量.结果 BPA在0.1 ～20μg/L范围内线性关系良好,相关系数r2＞0.997.BPA的加标回收率为91.85％ ～ 106.75％,相对标准偏差为4.80％ ～ 15.36％,检出限为0.010 μg/L,方法定量限为0.035μg/L.结论 本方法可满足母乳中游离态双酚A含量评估的需要.     

超高效液相色谱-串联质谱法测定麦芯粉中四种交链孢毒素

探讨固相萃取方法,超高效液相色谱串联质谱仪(UPLC-MS/MS)测定麦芯粉中4种交链孢毒素。样品经0.05 mol/L Na H2PO4(pH 3.0)-乙腈-甲醇超声提取(450+450+100,V/V),上清液过HLB固相萃取柱净化,以1.0 mmol/L氨水溶液(pH 8.3)-甲醇为流动相,经Waters CORTECS C18(4.6×100 mm,2.7μm)柱分离梯度洗脱,采用电喷雾负离子(ESI-)、多反应监测(MRM)模式检测;以基质加标工作曲线定量。细交链孢菌酮酸(TeA)、交链孢酚(AOH)在2.0μg/L~100μg/L浓度范围内,腾毒素(TEN)、交链孢酚单甲醚(AME)在0.2μg/L~10.0μg/L浓度范围内线性关系良好,相关系数(R2)均大于0.998。回收率为76.3%~107.5%,TeA、AOH检出限和定量限分别为1.0μg/kg和3.0μg/kg、TEN、AME检出限和定量限分别为0.1μg/kg和0.3μg/kg。该方法灵敏度高,简便,准确。适于测定麦芯粉中的交链孢毒素。     

QuEChERS-超高效液相色谱-串联质谱法测定水产品中6种氟喹诺酮类抗生素残留量

目的建立一种基于QuEChERS结合超高效液相色谱-串联质谱(UPLC-MS/MS)测定水产品中诺氧沙星、环丙沙星、洛美沙星、恩诺沙星、氧氟沙星和培氟沙星的分析方法。方法样品经1%甲酸乙腈提取,采用改进的QuEChERS体系进行净化后通过C_(18)色谱柱(2.1 mm×100 mm, 1.7μm),以0.1%甲酸水和甲醇-乙腈(4∶6,V/V)为流动相进行梯度洗脱,用UPLC-MS/MS法进行定性、定量分析。结果诺氧沙星、环丙沙星、洛美沙星、恩诺沙星、氧氟沙星和培氟沙星在一定浓度范围内具有良好的线性关系,相关系数(r)均大于0.999,检出限为0.30～0.80μg/kg,定量限为1.0～2.5μg/kg,回收率范围为86.6%～120%,相对标准偏差在0.59%～7.6%之间。结论该方法快速、准确,能满足水产品中6种氟喹诺酮类抗生素残留的快速筛查和检测分析要求。     

固相萃取-超高效液相色谱-三重四极杆质谱法测定甘蔗中3-硝基丙酸

目的建立固相萃取-超高效液相色谱-三重四极杆质谱联用技术(solidphaseextraction-ultra performanceliquidchromatographytandemmassspectrometry,SPE-UPLC-MS/MS)测定甘蔗中3-硝基丙酸(3-nitropropionic acid, 3-NPA)的分析方法。方法甘蔗汁和甘蔗渣经PSA固相萃取提取净化,以1%氨水甲醇溶液洗脱,氮吹吹干定容于0.5%甲酸水溶液中,以Waters HSS T3色谱柱(2.1 mm×50 mm, 1.8μm)在流动相乙腈-水(1:1,V:V)条件下进行分离,电喷雾负离子MRM模式下检测,以基质标准曲线定量。结果甘蔗汁中3-硝基丙酸的线性范围为5～1000μg/kg,检出限(S/N=3)为1.2μg/kg,甘蔗渣中线性范围为10～1000μg/kg,检出限(S/N=3)为2.7μg/kg。甘蔗汁和甘蔗渣3-NPA的加标回收率为96.5%～101.2%,相对标准偏差为1.54%～5.35%。结论该方法简单、灵敏、准确,可用于甘蔗中3-硝基丙酸检测。     

固相萃取-高效液相色谱法测定水产品中的甲基睾酮残留量

建立水产品中甲基睾酮残留量的固相萃取-高效液相色谱测定方法。样品经乙醚振荡提取、蒸发浓缩、正己烷除脂、LC-C18柱净化后吹干定容,以甲醇-0.1%甲酸溶液(75:25,V/V)为流动相经反相高效液相色谱检测定量。方法在7.0～200μg/kg添加范围内的平均回收率为82.0%～86.0%,相对标准偏差均小于7%,定量限为7.0μg/kg。     

固相萃取-高效液相色谱法测定鲫鱼肉中微囊藻毒素

建立固相萃取-高效液相色谱法(SPE-HPLC)测定鲫鱼肉中微囊藻毒素的方法.鲫鱼肉经90%甲醇水溶液提取,反相硅胶萃取柱净化后,采用高效液相色谱法进行测定.以乙腈-水-三氟乙酸(体积比35:65:0.05)为流动相,经Zorbax Eclipse C18柱(4.6mm×250mm i.d.5μm)分离,外标法定性、定量分析,结果表明微囊藻毒素LR的线性定量范围0.1～10.0μg/mL,鲫鱼肉中检出限25 ng/g.微囊藻毒素RR的线性定量范围0.1～10.0 μg/mL,在鲫鱼肉中的检出限20ng/g.此方法准确,灵敏度高,专属性好,可作为监测淡水水产品微囊藻毒素污染的分析方法.     

QuEChERS-高效液相色谱串联质谱法快速筛查分析食品中五氯酚酸钠残留

目的建立动物性食品中五氯酚酸钠(pentachlorophenol sodium, PCP-Na)残留的高效液相色谱串联三重四级杆质谱(high performance liquid chromatography tandem mass spectrometry, HPLC-MS/MS)快速筛查分析方法。方法样品采用80%乙腈水溶液提取,提取液经QuEChERS净化管净化、氮吹浓缩并以40%甲醇定容。以甲醇-5 mmol/L乙酸铵水溶液为流动相梯度洗脱,经Waters Acquity UPLC HSS T3(2.1 mm×100 mm, 1.7μm)色谱柱分离,质谱采用负离子电喷雾离子化(ESI-)、多反应监测(multiple reaction monitoring, MRM)模式定性和定量。结果方法线性范围为0.3～20.0μg/L(r0.999),对于畜禽类动物性食品,加标浓度为2.0μg/kg和10.0μg/kg时回收率范围为68.5%～99.3%,相对标准偏差为1.7%～16.2%(n=6)。方法检出限为0.1μg/kg,定量限为0.3μg/kg。结论本方法样品前处理快速、简单,检测灵敏度高、选择性好,适用于大批量动物性食品样品中痕量五氯酚酸钠残留的快速筛查分析。     

高效液相色谱-串联质谱法测定奶豆腐中6种喹诺酮类药物残留研究

目的 建立动物源性食品奶豆腐中6种喹诺酮类药物残留的高效液相色谱-串联质谱(UPLC-MS/MS)检测方法。方法 奶豆腐样品经0.1 mmol/L EDTA-Mcllvaine缓冲液处理并加入亚铁氰化氢、乙酸锌各0.1 mL提取,HLB Pro固相萃取柱净化,经Shim-pack FC-ODS(150 mm×20 mm,3μm)分离,用10 mmol/L乙酸铵(含0.1%甲酸)-甲醇乙腈(40:60,V/V)进行梯度洗脱,在全扫描(full MS)模式检测。结果 6种喹诺酮类药物在10～100 ng/mL的浓度范围内线性良好,相关系数(R2)均大于0.995;检出限(LOD)为0.5～1.5μg/kg,定量限为(LOQ)2～4μg/kg,加标回收率为82.3%～101.6%,相对标准差低于10%。结论 该方法灵敏度高、快速、准确,适用于奶豆腐中6种喹诺酮类药物的快速筛查和定量定性分析。     

液相色谱串联质谱法检测鲍鱼汁中的酸性橙Ⅱ

目的建立了液相色谱/串联质谱(HPLC-MS/MS)测定鲍鱼汁中酸性橙Ⅱ的方法,并用于实际样品的分析。方法样品经甲醇+乙酸铵溶液(体积比为1+1)振荡提取后用OASISWAXSPE柱净化,以乙腈-乙酸铵缓冲溶液为流动相,在C18色谱柱(2.1mm×50mm,1.7μm)上经梯度洗脱分离后以多反应监测质谱测定(m/z326.9→170.8,326.9→155.8)。结果方法的最低定量浓度(LOQ)为0.1mg/kg,5和50mg/kg两个水平加标样的平均回收率分别为87.0%和101.0%,线性相关系数为0.999,线性范围为10～5000μg/L。对14份食品专项整治抽检样品进行分析检测,其中7份检出酸性橙Ⅱ,其含量范围为1.2～73.8mg/kg。结论该方法能够满足鲍鱼汁中酸性橙Ⅱ的测定要求。     

Lipid and fatty acid composition of rabbit meat: Part 1.-Apolar fraction

The apolar lipid contents and the fatty acid composition of meat from two rabbit breeds (New Zealand white and commercial hybrid HYLA) fed two commercial diets of different protein and crude fibre levels have been studied. The total and apolar lipid content of meat from both rabbit breeds ranged from 4·9 to 10·5% (wet weight). The individual lipid classes of the apolar fraction are described. Triglycerides accounted for more than 80% of total apolar lipids. The fat from rabbit meat is comparatively richer in palmitic acid (about 40% being always the major fatty acid), in linoleic acid and in myristic acid and poorer in stearic acid than other meats. Although differences in the fatty acid compositions of meat were observed, only clear influences of age, sex, breed, and/or feeding on the fatty acids C-16:0, C-18:0 and C-18:2 of total and apolar lipids were found.     

鳄鱼肉与其他肉类营养成分的比较分析

为了进一步挖掘鳄鱼肉的营养价值,以鳄鱼肉、猪肉、牛肉、鸡肉、羊肉、河虾肉和鲫鱼肉为研究对象,采用国家标准检测方法,分析和测定其含有的主要营养成分并进行营养评价.结果表明:与其他肉类相比,鳄鱼肉中磷含量最高;鳄鱼肉中钙含量显著高于其他畜禽肉(P<0.05),是一种优质补钙食品,鳄鱼肉中水溶性维生素含量最高,鲜味氨基酸含量...     

云南武定鸡、盐津乌骨鸡和大围山微型鸡肌肉中脂肪酸的组成分析

以云南省特有的三个优质地方鸡品种:武定鸡、盐津乌骨鸡、大围山微型鸡为研究对象,用溶剂提取法提取3种鸡胸肌及腿肌中总脂质,经甲脂化后,利用气相色谱-质谱(GC-MS)对脂肪酸组成及含量进行分析。结果显示,在云南武定鸡、盐津乌骨鸡和大围山微型鸡胸肌及腿肌中共含有20种脂肪酸,主要包括油酸、亚油酸、棕榈酸、硬脂酸、花生四烯酸。武定鸡与盐津乌骨鸡胸肌中总脂肪含量分别为28.470与25.042 mg/g,显著高于大围山微型鸡的16.769 mg/g(p0.05),大围山微型鸡腿肌中总脂肪含量为51.10 mg/g,显著高于武定鸡40.994 mg/g(p0.05);三种鸡的脂肪酸种类相同,饱和、不饱和脂肪酸占总脂肪酸比例相似,但各脂肪酸含量有所差异,三个鸡种腿肌中脂肪酸含量显著高于胸肌中脂肪酸含量(p0.05)。     

Metabolic fate of long-chain unsaturated fatty acids and their effects on palmitic acid metabolism and gluconeogenesis in bovine hepatocytes

The objectives were to determine the metabolic fate of different long-chain fatty acids, and their effects on palmitic acid metabolism and gluconeogenesis in bovine hepatocytes. Hepatocytes were isolated from four ruminating calves and exposed in suspension for 3 h to one of the following treatments: 1 mM palmitic acid (1C16), 2 mM palmitic acid (2C16), or 1 mM palmitic acid plus either 1 mM oleic (C18:1), linoleic (C18:2), linolenic (C18:3), eicosapentaenoic (C20:5), or docosahexaenoic acid (C22:6). Oxidation of [1-(14)C]palmitic acid or one of the [1-(14)C]-labeled treatment fatty acids to CO2 or incorporation into cellular triglycerides (TG), phospholipids, cholesterol, and cholesterol esters were measured. Rates of oxidation to CO2 were 3- to 4-fold higher for C22:6 than for other fatty acids, with the exception of C20:5, which had intermediate rates of oxidation to CO2. In general, treatments 2C16 and C18:1 yielded the highest rates of incorporation into most cellular lipids, whereas the polyunsaturated fatty acids were poor substrates for incorporation into cellular lipids. The most pronounced change was a large reduction of polyunsaturated fatty acid incorporation into cellular TG compared to 1C16, 2C16, and C18:1. The unsaturated fatty acids also influenced palmitic acid metabolism. The addition of C20:5 yielded the highest rates of palmitic acid oxidation to CO2 followed by addition of C18:1 and C22:6. Treatments containing polyunsaturated fatty acids decreased palmitic acid metabolism to TG and total cellular lipids compared with treatments 2C16 and C18:1. Rates of gluconeogenesis from propionate were significantly higher for the treatment containing C18:1. Long-chain fatty acids vary in their routes of metabolism and influence palmitic acid metabolism and gluconeogenesis in bovine hepatocytes.     

Stability of lipids and fatty acids in frozen and gamma irradiated Patagonian toothfish (Dissostichus eleginoides) from the Southwestern Atlantic

Patagonian toothfish were captured in the Southwestern Atlantic Ocean (FAO Zone N° 41). The fatty acid profile of total lipids and the triacylglycerol and phospholipid content of control and irradiated samples (1 and 5 kGy) stored at −18 °C were analyzed at 0 and 293 days post irradiation. The fatty acids are mainly monounsaturated acids (47 g/100 g total fatty acids), the most abundant one being oleic acid (18:1 n-9). This is followed in order of abundance by saturated fatty acids (26 g/100 g total fatty acids), consisting mainly of palmitic acid (16:0). Polyunsaturated fatty acids were less abundant (17 g/100 g total fatty acids) and consisted mainly of eicosapentaeonic (20:5 n-3) and docosahexaenoic (22:6 n-3) acids. Triacylglycerol content was 563.07 mg/mL oil, whereas phospholipids were 11.21 mg/mL oil. Gamma irradiation did not significantly affect the fatty acid profile or triacylglycerol and phospholipid content of P. toothfish stored for 293 days at −18 °C. The results suggest that the species exhibits a marked stability when subjected to irradiation and prolonged storage in the frozen state.     

鳄鱼肉主要营养成分及与其他畜禽肉的比较

为了充分了解鳄鱼肉的营养特性,更好地利用鳄鱼资源,本实验分析鳄鱼肉的主要组分、脂肪酸及氨基酸的构成,并与羊肉、猪肉、牛肉和鸡肉进行比较.结果表明:与其他畜禽肉相比,鳄鱼肉是一种高蛋白、低脂肪的优质肉品,多不饱和脂肪酸含量丰富,尤其是花生四烯酸、二十碳五烯酸(EPA)和二十二碳六烯酸(DHA).鳄鱼肉富含必需氨基酸,尤其是赖氨酸.且根据必需氨基酸指数,鳄鱼肉的营养价值高于其他畜禽肉.综合看来,鳄鱼肉是较理想的动物蛋白及脂肪来源.     

GLC-MS Analysis of Fatty Acids From Five Black Walnut Cultivars

The lipids from kernels of five black walnut cultivars were extracted by solvent extraction and the fatty acids were analyzed as their methyl esters by GLC-MS analyses. Twenty-one fatty acids were identified in each cultivar. Five acids, palmitic, stearic, oleic, linoleic and linolenic, were present in quantities greater than 1% of total lipids present. Quantities of the individual fatty acids varied significantly among cultivars (P > 0.05) except for palmitic. Linoleic was the predominant fatty acid in all cultivars. Oleic and linoleic comprised greater than 85% of the lipids present in the walnut kernels.     

Changes in lipid composition and fatty acid profile of Nham,a Thai fermented pork sausage,during fermentation

Changes in lipid composition and fatty acid profile of Nham during fermentation were investigated. Total lipids of Nham were in the range 2–3%. The extracted lipid of initial Nham mix consisted mainly of triglycerides (TG), accounting for more than 75% of the total lipid, followed by phospholipids (PL) and a trace amount of diglycerides (DG) and free fatty acid (FFA). During fermentation, TG, DG and PL decreased with a concomitant increase in FFA, indicating lipolysis of Nham lipids during fermentation. Changes in fatty acids of the total lipids, non-polar and polar lipid fractions were observed during fermentation. In both total and non-polar lipid fractions, the major fatty acids found in a descending order were oleic (C18:1), linoleic (C18:2) and palmitic (C16:0) acids, which together accounted for 90% of the total fatty acids. Increases in fatty acid contents in both total and non-polar lipid fractions, were observed with a corresponding decrease in the quantity of fatty acids of phospholipids. As the fermentation proceeded, peroxide value generally increased while TBARS values decreased. Overall, lipid oxidation in Nham occurred during fermentation but did not cause the objectionable odour and taste in any Nham tested.     

Variations in the composition of various acyl lipids,tocopherols and lignans in sesame seed oils roasted in a microwave oven

Seeds from various strains of cultivated Sesamum indicum Linn (colour of seeds: black, brown and white) were exposed to microwave roasting for 16 and 30min at a frequency of 2450 MHz and were studied not only for different acyl lipids and their fatty acid compositions, but also for the contribution of anti-oxidants to the oxidative stability of the oils. Lipids from all-seeded strains were comparable in their total fatty acid composition, with linoleic, oleic, stearic and palmitic acids as the major acids. The total lipids were isolated by thin-layer chromatography into the following five fractions: triacylglycerols (TAG), diacylglycerols, free fatty acids, polar lipids and steryl esters. The TAG were slightly and randomly hydrolysed by microwaves, but was still representing 900 g kg^?1 of the total lipids at 30min of roasting. Although burning and bitter tastes occurred at the time, the tocopherols and lignans still amounted to over 80% of the original level. The results suggested that the oxidative stability of the oils would probably be due to the synergism between endogenous antioxidants and browning substances produced during microwave roasting.     

发酵条件对发酵性丝孢酵母脂肪酸组成的影响

通过摇瓶发酵，研究了温度、摇瓶转速、碳源种类和浓度对发酵性丝孢酵母（Trichosporom fermentans）脂肪酸组成的影响。气相色谱法分析结果表明，较高发酵温度能提高菌体油脂的脂肪酸饱和程度，此条件下饱和脂肪酸含量占脂肪酸总量的49．1％：摇瓶转速高有利于菌体油脂不饱和脂肪酸的生成；木糖浓度为100g／L时菌体油脂中饱和脂肪酸含量最高，占脂肪酸总量的50．4％；木糖比葡萄糖更容易被转化生成饱和脂肪酸含量较多的油脂。菌体脂肪酸组成包括肉豆蔻酸、棕榈酸、棕榈油酸、硬脂酸、油酸和亚油酸，其中棕榈酸和油酸含量较高。