固相萃取-亲水作用色谱法检测奶粉中的三聚氰胺

采用固相萃取-亲水作用色谱法对奶粉中的三聚氰胺进行测定.样品经0.1%TFA甲醇提取,Strata X-C固相萃取小柱净化,用Phenomenex Luna HIlIC柱分离,乙腈-0.1%甲酸[90∶10)为流动相,经液相色谱检测.结果表明,三聚氰胺在1～50μg/mL的浓度范围之间具有良好的线性关系(R2=0.9998),加标回收率大于90%.该方法简单,精密度和准确度高,适用于奶粉中三聚氰胺的测定.     

高效液相色谱法快速测定乳粉中的三聚氰胺与双氰胺

建立高效液相色谱-二极管阵列检测器同时检测乳粉中三聚氰胺和双氰胺的分析方法。采用1%三氯乙酸溶液提取样品中的三聚氰胺和双氰胺,氨基柱为分析柱,流动相为乙腈-水（75∶25,V/V）,流速1.0 mL/min,检测波长233 nm。2 种物质在0.005～60 mg/L范围内与其峰面积线性关系良好,不同添加水平的回收率在83.2%～102.6%,三聚氰胺和双氰胺的方法定量限分别为0.17、0.15 mg/kg,方法变异系数为2.3%～7.2%（n=6）。此方法操作简便、快速、成本低,适用于乳粉中三聚氰胺和双氰胺的同时检测。     

高效液相色谱法测定乳与乳制品中的三聚氰胺

目的建立乳与乳制品中三聚氰胺的测定方法。方法样品用0.1 mol/L的盐酸提取,再用60 g/L的磺基水杨酸沉淀蛋白。缓冲液为10 mmol/L柠檬酸与10 mmol/L辛烷磺酸钠混合溶液,以缓冲液 乙腈(85 15,体积比)为流动相,使用Kromasil KR100-5C8柱,配备有二极管阵列检测器的高效液相色谱仪在200~400 nm范围内对待测组分进行分离和测定。结果样品中三聚氰胺的添加回收率在80%~105%之间,相对标准偏差(RSD,n=6)小于5.24%,方法的定量限为1.0 mg/kg。结论该方法快速、准确,操作简便,能够满足乳与乳制品中三聚氰胺的分析要求。     

Fast Determination of Sodium Monofluoroacetate in Liquid Milk and Dairy Powder by Hydrophilic Interaction Liquid Chromatography-Triple Quadrupole Mass Spectrometry

Manufactured sodium monofluoroacetate is a rodenticide with high acute toxicity. A fast and sensitive analytical method in liquid milk and dairy powder was developed both for routine analysis and for fast tackling the terrorist threat. Monofluoroacetate was extracted from liquid milk using acetonitrile and from dairy powder with water and acetonitrile, cleaned using a solid phase extraction (SPE) cleanup procedure with polymeric anion exchange (PAX) cartridge, and measured by hydrophilic interaction liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS). The conditions for the monofluoroacetate extraction, SPE cleanup, and instrument injection solvent were optimized. A BEH amide chromatographic column with hydrophilic interaction was used to directly separate monofluoroacetate under basic conditions. The limits of detection in liquid milk and dairy powder were 1 and 2 μg kg^-1, respectively. The recoveries at three spiking levels (10, 50, and 200 μg kg^-1) were 72.5–97.6 % with relative standard deviations (RSDs) of 4.7–5.9 % for liquid milk and 70.1–92.8 % with RSDs of 4.7–6.8 % for dairy powder. The method has been applied to analyze sodium monofluoroacetate in dairy products including infant formula.     

高效液相色谱法测定乳粉及液态奶中牛磺酸含量

建立高效液相色谱法测定乳粉和液态奶中牛磺酸含量。样品用水溶解,超声提取10 min,提取液经亚铁氰化钾和乙酸锌沉淀蛋白后,离心,上清液用异硫氰酸苯酯和三乙胺衍生化,室温衍生1 h,加入正己烷为衍生化终止剂,静置分层,下层溶液用水定容后过0.22μm微孔滤膜,过滤液经Diamonsil AAA氨基酸分析柱(4.6×250 mm,5μm)分离,以0.05 mol/L乙酸钠水溶液(pH值=6.50)和甲醇/乙腈(1/1,V:V)为流动相进行梯度洗脱。采用外标法定量,在5.0～40μg/mL线性范围内相关系数(r)大于0.999,线性关系良好,定量限为5 mg/100 g(S/N≥10),添加水平为5、10、25 mg/100 g时,回收率范围在90%～108%之间,相对标准偏差范围为1.16%～2.24%。结果显示,本方法准确、可靠,满足乳粉和液态奶中牛磺酸含量的有效确定,特别对于特膳奶粉比GB方法更适合样品中牛磺酸含量的有效检测。     

亲水作用色谱-串联质谱法测定婴幼儿乳粉中的牛磺酸

目的:建立婴幼儿乳粉中牛磺酸直接测定的亲水作用色谱-串联质谱(HILIC-MS/MS)检测方法。方法:样品经提取后,采用乙腈和10 mmol/L甲酸铵(0.05%甲酸)作为流动相进行梯度洗脱,质谱在负离子模式下采用多反应监测(MRM),对牛磺酸进行定量测定。结果:牛磺酸在10~200 ng/mL浓度范围线性关系良好,相关系数r为0.9997,检出限为0.04 mg/kg,回收率在81.2~90.5%之间,相对标准偏差小于4.0%。结论:该方法快速、准确、灵敏度高,可用于婴幼儿乳粉中中牛磺酸的直接测定。     

固相萃取-毛细管电泳法测定奶粉中三聚氰胺的含量

建立了高效毛细管电泳法测定奶粉中三聚氰胺含量的方法。在背景电解质溶液为30mmol/L的硼砂缓冲液中加入15mmol/L的十二烷基硫酸钠(SDS),运行电压为15kV,压力进样为10s,柱温为25℃,检测波长为200nm。结果表明:三聚氰胺的线性范围20~50μg/mL(r=0.9994),平均回收率为99.3%,检出限为1μg/mL,定量限为2μg/mL。结论是本法简便快捷,结果准确可靠,可作为该成分的质量控制方法。     

高效液相色谱测定生鲜乳及乳制品中三聚氰胺的方法研究

建立用高效液相色谱.二极管阵列法测定生鲜乳及乳制品中的三聚氰胺的检测方法.本实验参照FDA三聚氰胺检测方法、NY/T 1372-2007,探讨检测三聚氰胺的色谱条件和优化生鲜乳及乳制品中的三聚氰胺前处理方法.最后确立了有效的检测方法,采用硫酸铵(0.02mol/L):甲醇=94:6(V/V)作为流动相,203nm为检测波长.样品溶液在0.1～150μg/ml之间均具有良好的线性关系,最低检测限为0.5mg/kg,回收率均在91%以上,回归方程式为y=2.37×105x 1.21×104及相关系数r=0.9998.此法操作简便、快速、灵敏、准确,样品处理简便易行,适于测定生鲜乳及乳制品中的三聚氰胺.     

Separation of Steviol Glycosides by Hydrophilic Liquid Interaction Chromatography

Stevia rebaudiana Bertoni contains several steviol glycosides with sweet flavour. They all are sweeter than sucrose (up to factor 450). The various steviol glycosides are difficult to separate by reversed-phase chromatography. In this paper, five different hydrophilic liquid interaction chromatography columns are characterized using isocratic elution (5–20% water in acetonitrile with buffer or formic acid). Separation of the steviol glycosides is possible with all but one of the tested columns, but the robustness of the separation against changes of buffer concentration and percentage of water differ. Aqueous percentage and ion strength of the eluent are the main factors to be optimized in method development.     

气相色谱串联质谱法测定奶粉,液态奶及鸡蛋中三聚氰胺的含量

利用气相色谱串联质谱检测方法,对奶粉,液态奶及鸡蛋试样中的三聚氰胺用无水甲醇超声提取,经混合型阳离子交换固相萃取柱净化,且净化液用BSTFA+TMCS(99:1)进行硅烷化衍生,衍生产物采用选择离子监测质谱扫描模式,用化合物的保留时间和质谱碎片的丰度比定性,外标法定量.方法最低检出限为0.05 mg/kg,回收率范围为72%～88%,相对偏差为0.38%～0.52%.     

傅立叶变换红外光谱法测定奶粉中三聚氰胺的含量

建立红外光谱法定量测定奶粉中三聚氰胺的方法,为三聚氰胺无损检测提供理论依据。选取1 551 cm-1附近特征吸收峰,建立线性定量模型。红外光谱法测定奶粉中三聚氰胺相关度高达0.999 2,准确度高、稳定性好、检测限低,样品回收率为98.89%。运用红外光谱法测定奶粉中三聚氰胺的含量是可行的。     

反相高效液相色谱法检测奶粉中含硫氨基酸

目的：建立奶粉中含硫氨基酸反相高效液相色谱检测方法,为含硫氨基酸检测提供新思路。方法：用常规酸水解和氧化水解法水解奶粉,对水解条件和色谱分离和检测条件进行研究,用反相高效液相色谱法测定奶粉中的含硫氨基酸。结果：蛋氨酸(Met)、胱氨酸[(Cys)2]检出限分别为0.7、0.3μmol/L,定量检测范围均为10～300μmol/L,相关系数分别为0.9993、0.9992。经酸水解和氧化水解处理的奶粉,所测得的Met含量无显著差异,均为0.43g/100g,(Cys)2的含量则分别为0.06、0.14g/100g,差异显著。结论：奶粉中Met含量的高效液相色谱HPLC检测可选用酸水解或氧化水解中任一种前处理方法,(Cys)2含量的测定只能采用氧化法进行前处理。     

三重四极杆气质联用法分析乳粉中三聚氰酸和三聚氰胺

建立三重四极杆气相色谱质谱联用分析乳粉中三聚氰酸和三聚氰胺的方法。样品以甲醇提取,利用衍生化试剂BSTFA-TMCS(99:1,V/V)进行衍生化处理、优化仪器条件、考察基质效应,利用三重四极杆气质联用的多反应监测(MRM)技术,对三聚氰酸和三聚氰胺衍生物进行定性定量分析,以三聚氰酸衍生物离子对m/z345>215、m/z345>330离子对进行定性,以m/z345>215进行定量;以三聚氰胺衍生物离子对m/z342>171、m/z342>327离子对进行定性,以m/z342>327进行定量。方法在0.010～0.500mg/L范围内呈良好的线性关系。方法分析三聚氰酸和三聚氰胺的检测限分别为0.016、0.003mg/kg,精密度为4.5%～8.6%、3.9%～6.2%和回收率分别为84.0%～102.0%、88.5%～104.0%。为乳粉中三聚氰酸和三聚氰胺的检测提供了准确可靠的方法。     

Determination of Melamine by Differential Pulse Polarography/Application to Milk and Milk Powder

Melamine made headlines in September 2008 because it was found to be the contaminant responsible for the deaths of several infants and making many more sick. Determination of trace melamine is very important. Therefore, in this work a novel, sensitive and reliable method was developed using differential pulse polarography. The most suitable buffer system was found to be Britton–Robinson (B–R) buffer, pH 11.2. The melamine peak in this medium appeared at about −50 mV, it responded well to standard additions and high reproducibility was obtained. The calibration graph was linear in the concentration range of melamine from 1.0 to 66.4 μM with a correlation coefficient of 0.999. The limit of detection (LOD) and limit of quantification (LOQ) were obtained as 0.3 and 1.0 μM, respectively. The current was characterized as being adsorption-controlled process. The proposed method was successfully applied to the determination of melamine in spiked milk and milk powder. The linear dynamic ranges observed for melamine concentration in milk and milk powder samples were between 1–58 and 10–57 μM, respectively. The sufficiently good recoveries and low standard deviations for the data reflect the high accuracy and precision of proposed differential pulse polarographic method.     

气相色谱法测定婴幼儿配方乳粉中的OPO含量

建立气相色谱法测定婴幼儿配方乳粉中OPO的含量。乳粉中的油脂经乙醚与石油醚萃取后,通过旋转蒸发浓缩,以十七烷酸甘油三酯为内标物。利用带有FID检测器的气相色谱仪对其中的OPO含量进行测定分析,并对色谱条件优化。优化后OPO的线性范围为0.1~0.5 g/100 g,相关性R^2为0.9998。检出限为0.04 g/100 g,定量限为0.14g/100 g。当加标浓度为2.4~4.4 g时,加标回收率为92.97%±5%,相对标准偏差RSD为2.57%(N=6)。该方法可靠、简便,可准确测定婴幼儿配方乳粉中OPO含量。     

反相高效液相色谱法快速测定婴儿配方乳粉中的维生素A酯类化合物

目的：开发一种快速测定婴儿配方乳粉中维生素A 酯类含量的反相高效液相色谱法。方法：直接使用二氯甲烷和甲醇体积比为2.5:1 的混合溶剂对样品进行提取,在30℃的条件下采用等度洗脱,流动相采用体积比为80:20 的甲醇- 三氯甲烷溶剂,流动相流速1.0mL/min;色谱柱温度30℃,检测波长325nm。结果：维生素A 醋酸酯和维生素A 棕榈酸酯的回收率分别为100.1% 和102.8%,多次测定结果的相对偏差分别为1.18% 和0.96%,检出限分别为3.1ng 和4.3ng。结论：本方法操作简单、精密度、回收率和灵敏度高,适用于婴幼儿配方乳粉中的维生素A 酯类的检测。