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建立乳与乳制品中香兰素、甲基香兰素、乙基香兰素和香豆素的反相高效液相色谱分析方法。用乙腈作为提取剂,氮吹浓缩,正己烷除脂净化,以C18反相色谱柱分离,20 mmol/L乙酸铵缓冲溶液(pH 5.6)-乙腈-甲醇为流动相,采用梯度方式洗脱,紫外检测波长267 nm,外标法定量。结果表明:4 种香兰素类化合物在0.05~5.00 μg/mL范围内线性良好,液态乳、乳粉、发酵乳、乳酸菌饮料、雪糕和干酪样品中香兰素、甲基香兰素、乙基香兰素和香豆素的定量限均为0.2 mg/kg,检出限均为0.06 mg/kg;液态乳、乳粉、发酵乳、乳酸菌饮料、雪糕和干酪中香兰素、甲基香兰素、乙基香兰素和香豆素添加量为0.2~2.0 mg/kg时,加标回收率分别为80.6%~110.0%、80.1%~109.6%、80.4%~109.5%、80.1%~105.9%,相对标准偏差分别为1.87%~7.70%、1.45%~9.80%、1.66%~9.52%、1.16%~9.52%。本方法快速、准确、重复性好、操作简便,适用于乳制品中香兰素、甲基香兰素、乙基香兰素和香豆素的含量测定。 相似文献
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高效液相色谱法同时测定乌骨鸡肌肉中的黑色素与肌苷酸 总被引:2,自引:0,他引:2
研究建立了同时测定乌骨鸡肌肉中黑色素与肌苷酸含量的高效液相色谱分析方法.鸡肉样品经酶解后,分离肌苷酸待测溶液与纯化黑色素粗品;黑色素粗品再在碱性条件下经过氧化氢氧化为2,3,5-三-羧酸吡咯(PTCA).肌苷酸待测溶液溶解PTCA成供试样品,在高效液相色谱仪中通过C18柱分离,紫外检测器检测波长270 nm,甲醇-磷酸/三乙胺缓冲液作为流动相等度洗脱.PTCA定量后以乌贼黑色素为对照品换算黑色素含量,外标法定量.结果表明:PTCA回收率为68.22%~75.21%,RSD值为6.83%~6.92%(n=6);肌苷酸回收率为79.26% ~88.26%,RSD值为1.92%~2.35%(n=6).黑色素、肌苷酸的检测限分别为10μg/g、100 μg/g.该方法灵敏、可靠,少量乌骨鸡样本即可实现同时、快速检测黑色素与肌苷酸含量. 相似文献
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为探讨中药对河南省规模化养猪场致病性大肠杆菌(E.coli)耐药质粒消除的效果,本研究在对87个猪致病性E.coli分离株进行耐药质粒检测的基础上,将各分离株分别于含有不同浓度的石榴皮、黄芩、黄连等中药提取液的培养液中培养,进行耐药质粒消除试验;并采用影印培养法和纸片扩散法进行耐药性消除菌落筛选及其对抗菌药物敏感性恢复的检测.结果表明:各分离株均含有2个~8个质粒,大小约为1.0 kb~87.0 kb;经石榴皮、黄芩、黄连作用后,各分离株均可以获得数量不等的耐药性消除菌落,消除率为0.34%~16.2%,以黄连的平均消除率最高,为9.33%;在耐药性消除的各分离株中,有25个分离株未发生质粒消除,其余均消除了1条~3条质粒,并且对7种抗菌药物的平均敏感率由消除前的5.39%分别提高至60.4%、75.2%和76.5%.表明石榴皮、黄芩、黄连对猪致病性E.coli具有质粒消除和耐药性逆转作用,其中黄连作用效果最好. 相似文献
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建立液态乳中2种紫外吸收剂(UV-326和UV-1577)和2种抗氧化剂(AO-1010、AO-2246)的高效液相色谱测定方法.前处理采用乙腈提取液态乳中目标化合物,样品用正己烷提取;检测经Agilent HC-C8反相色谱柱,以乙腈-水作为流动相,梯度洗脱程序进行分离,280 nm波长下检测.结果表明:分析物在0.05~50 μg/mL质量浓度范围内线性关系良好,线性相关系数>0.999 5,方法检出限为0.02~0.5 mg/kg.方法在3个水平的加标回收率为69.08%~115.87%,相对标准偏差为0.43%~9.94%.该方法操作简单、灵敏度高、重现性好,适用于液态乳中紫外吸收剂和抗氧化剂的同时测定. 相似文献
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Lipid microencapsulation allows slow release of organic acids and natural identical flavors along the swine intestine 总被引:2,自引:0,他引:2
The purpose of the present work was to investigate the in vivo concentrations of sorbic acid and vanillin as markers of the fate of organic acids (OA) and natural identical flavors (NIF) from a microencapsulated mixture and from the same mixture non-microencapsulated, and the possible consequences on the intestinal microbial fermentation. Fifteen weaned pigs were selected from 3 dietary groups and were slaughtered at 29.5 +/- 0.27 kg of BW. Diets were (1) control; (2) control supplemented with a blend of OA and NIF microencapsulated with hydrogenated vegetable lipids (protected blend, PB); and (3) control supplemented with the same blend of OA and NIF mixed with the same protective matrix in powdered form but without the active ingredient coating (non-protected blend, NPB). Stomach, cranial jejunum, caudal jejunum, ileum, cecum, and colon were sampled to determine the concentrations of sorbic acid and vanillin contained in the blend and used as tracers. Sorbic acid and vanillin were not detectable in pigs fed the control, and their concentrations were not different in the stomach of PB and NPB treatments. Pigs fed PB showed a gradual decrease of the tracer concentrations along the intestinal tract, whereas pigs fed NPB showed a decline of tracer concentration in the cranial jejunum and onwards, compared with the stomach concentrations. Sorbic acid and vanillin concentrations along the intestinal tract were greater (P = 0.02) in pigs fed PB compared with pigs fed NPB. Pigs fed PB had lower (P = 0.03) coliforms in the caudal jejunum and the cecum than pigs fed the control or NPB. Pigs fed the control or PB had a greater (P = 0.03) lactic acid bacteria plate count in the cecum than pigs fed NPB, which showed a reduction (P = 0.02) of lactic acid concentrations and greater (P = 0.02) pH values in the caudal jejunum. The protective lipid matrix used for microencapsulation of the OA and NIF blend allowed slow-release of both active ingredients and prevented the immediate disappearance of such compounds upon exiting the stomach. 相似文献
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Tall fescue hay (H) supplemented with corn and urea (HU) or corn gluten meal (HCGM) and ammoniated tall fescue hay supplemented with corn (AH) or corn gluten meal (AHCGM) were fed to steers in two 4 X 4 Latin-square trials. Diets were fed to four Angus-Hereford steers (550 kg) at equal intakes in trial 1 and to four Hereford steers (350 kg) at ad libitum intakes in trial 2. Ammoniation reduced cell wall concentrations of p-coumaric acid and ferulic acid by 48 and 67%, respectively. Concentrations of other phenolics were also reduced. Apparent total tract digestibilities of vanillin, p-coumaric acid and ferulic acid were lower (P less than .05, .001 and .01, respectively) when nontreated hay was fed in trial 1, but were not different between hay types in trial 2. In trial 1, greater negative intestinal digestibilities of p-coumaric acid (P less than .001) and vanillin (P less than .05) occurred for steers fed HU and HCGM vs AH and AHCGM diets. Digestibilities of neutral detergent fiber (NDF) and acid detergent fiber (ADF) were greater (P less than .001) for steers fed ammoniated hay diets in both trials and greater (P less than .05) for HCGM vs HU in trial 1. More than 96% of the NDF and ADF digested by steers in trial 1 was digested in the stomach. Intakes of digestible NDF and ADF, but not indigestible NDF or ADF, were higher (P less than .001) for steers fed AH and AHCGM in trial 2. In situ dry matter disappearance rate of ammoniated hay was greater (P less than .05) than that of nontreated hay, but rate of cotton thread disappearance from bags suspended in the rumen of steers fed the various diets was similar among treatments. In both trials, feeding ammoniated hay resulted in higher (P less than .05) ruminal concentrations of acetate and higher (P less than 0.05) acetate:propionate ratios. Ruminal liquid dilution rates were lower (P less than .05) for steers fed AH and AHCGM in trial 1, but were not different in trial 2. Ruminal dry matter concentration and solids dilution rate were not affected by diet in either trial. The results are interpreted to indicate that increased intake of ammoniated hay is a result of increased rate and extent of fiber digestion. 相似文献
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建立了UPLC同时测定桃金娘果中没食子酸、鞣花酸、白皮杉醇和白藜芦醇4种酚类物质的方法。桃金娘果样品经甲醇超声提取后采用WatersCORTECSUPLCT3色谱柱(2.1mm×100mm,1.6μm);流动相为乙腈-0.2%磷酸溶液进行梯度洗脱程序;流速0.2mL/min;柱温35℃;检测波长为280nm。结果显示桃金娘果中的4种成分10min内能够完全分离,在测定的质量浓度范围内线性关系良好,相关系数均大于0.9990;平均加样回收率在95.1%~102%之间,RSD1.5%~2.8%;检出限分别为7.55、2.32、63.7、4.59ng/mL。该法简便快速,具有较高准确性和重复性,可用于桃金娘果药材的质量控制。 相似文献
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4种豆科牧草总皂苷含量的测定及其生长过程中含量的变化 总被引:3,自引:2,他引:1
以香草醛-冰醋酸为显色剂,采用分光光度法,测定三萜皂苷的含量,对波长、精密度、重现性和稳定性进行检测。并分别对鹰嘴紫云英Astragalus sinicus、红豆草Onobrychis viciaefolia、百脉根Lotus cornicμLatus和小冠花Coronilla varia 4种豆科牧草中皂苷的含量进行测定。结果表明,此方法简便易行,精密度高,重现性好,在25 min内测试结果稳定可靠。4种豆科牧草在整个生育时期总皂苷含量的变化不完全一致。鹰嘴紫云英和红豆草在初花期总皂苷含量最低,产草量较高,牧草品质优良,适宜青饲或调制干草;盛花期总皂苷含量丰富,产草量最高,宜作为生产中提取皂苷产品的原料。小冠花总皂苷含量始终较低,是一种优质的豆科牧草,不会使反刍家畜产生臌胀病。红豆草、鹰嘴紫云英、小冠花和百脉根4种豆科牧草在整个生育期皂苷含量均为叶中多于茎中。 相似文献
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建立了超高效液相色谱-静电轨道阱质谱联用测定禽蛋中五氯苯酚残留量的分析方法。取均质后的禽蛋样品经乙腈溶液提取,加入无水硫酸镁和氯化钠进行脱水和盐析,高速离心分层后,取适量乙腈层溶液经0.1%(V∶V)甲酸稀释后,用酸性氧化铝粉末进行样品净化并以10000 r/min离心取上清液,过0.22μm滤膜后上机测定。使用反相色谱柱进行分离,流动相为乙腈:0.1%甲酸=75∶25,采用等度程序进行洗脱,静电轨道阱质谱进行定性定量分析。结果表明,五氯苯酚在0.5~100μg/kg范围内线性关系良好(r>0.995),方法的最低检出限为0.2μg/kg,最低定量限为0.5μg/kg,添加回收率在74.43%~96.85%之间,批内批间变异系数CV%<10%。该方法具有较好的准确度与精密度,适用于禽蛋中五氯苯酚残留量的测定。 相似文献
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开发建立了超高效液相色谱-二极管阵列-串联四级杆静电场轨道阱高分辨质谱联用分析杆菌肽组分的方法。采用(Phenomenex C18100 mm×3.0 mm,2.6μm)色谱柱,以0.1%甲酸溶液-0.1%甲酸甲醇乙腈(75+25)溶液为流动相,0.3 mL/min线性梯度洗脱分离,紫外吸收波长为254 nm。采集杆菌肽各组分质谱母离子及其对应子离子,并进行解析,推测组分的结构。在所建立的条件下,检测出9个组分,杆菌肽各组分之间分离良好。利用紫外与质谱归一化法测定含量,两种结果相对偏差在0.01%~3.53%之间。建立的超高效液相色谱-二极管阵列-串联四级杆静电场轨道阱高分辨质谱法能有效分析多肽类药物杆菌肽各组成成分,为杆菌肽的质量控制和工艺优化提供了参考。 相似文献
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建立高效液相色谱法测定乳与乳制品中柚皮苷含量的方法。样品用甲醇提取,在284 nm波长下,流动相为体积分数0.1%醋酸水溶液-乙腈(75∶25,V/V),C18色谱柱分离,经二极管阵列检测器检测,外标法定量。结果表明:柚皮苷在5~500 μg/mL质量浓度范围内线性关系良好,相关系数为0.999 9;分别向乳粉、液态乳和酸乳样品中在加入柚皮苷标准品0.02、0.04、0.08 g/100 g时,加标回收率分别为96.2%~103.2%、96.3%~103.7%和99.7%~104.1%,相对标准偏差分别为1.12%~2.31%、1.25%~1.85%和1.24%~1.66%。该检测方法简便、快速、准确、重复性好,能够测定乳与乳制品中柚皮苷的含量。 相似文献