紫外分光光度计检测十二烷基苯磺酸钠鉴别潲水油的方法研究

建立了潲水油中十二烷基苯磺酸钠(SDBS)的检测方法,样品经高纯水提取、三氯甲烷萃取、亚甲蓝显色后,以紫外分光光度法进行测定。考察了提取温度、提取时间等因素的影响。实验结果表明,水对食用油中SDBS的最佳提取时间为2 h,温度为50℃,检测波长为645 nm。方法检出限(LOD)为0.1μg/kg。加标量分别为1.0、5.0、10.0、20.0μg/kg时的回收率为94%～96%,相对标准偏差(RSD)均小于5%。5组实际样品的检测结果显示,潲水油中SDBS的残留量平均值为19.19μg/kg,优质食用油中SDBS的平均含量为0.35μg/kg。潲水油中SDBS的含量有很大差别,但总体均高于优质食用油中的含量,方法可用于潲水油和食用植物油的鉴别。     

顶空固相微萃取-气相色谱-质谱联用技术鉴别潲水油

采用顶空固相微萃取与气质联用法分析了潲水油样品中的挥发性成分,比较了不同萃取头和不同色谱柱对潲水油中挥发性成分的萃取分离效果。结果表明,65μmPDMS/DVB萃取头和DM-5MS色谱柱能萃取出较多潲水油中所特有的香辛料成分,萃取效果较好。通过大量潲水油和正常食用植物油做对比,找出了潲水油和正常食用植物油的差别成分:茴香脑、丁香酚及二氢大茴香脑。     

微波消解-电感耦合等离子体原子发射光谱法测定潲水油中25种元素的含量

正潲水油也被称为地沟油,是人们对生活中各类劣质食用油脂或非食用油脂的统称,其回流餐桌以及流入食品生产中的现象屡禁不止。在潲水油回收及加工过程中因受到污染或接触金属器皿等,常常会引入金属元素,因此金属元素含量超标是潲水油的重要特征,严重危害消费者的身体健康。目前,针     

现代仪器分析技术在潲水油检测中的应用

综述了近年来光谱、色谱、质谱、核磁共振等现代仪器分析技术在潲水油检测中的应用现状和发展,并对其应用前景进行了展望(引用文献46篇)。     

应用校正变换矩阵法识别掺伪食用油

根据食用油中脂肪酸、甾醇以及生育酚含量,应用校正转换矩阵法对花生油掺伪进行了定量检测。用所建立的校正模型对棕榈油、菜籽油和棉籽油掺入到花生油所得到的２７个二元和６个四元人工合成样品进行了验证,结果令人满意。对从市场上购得的５种花生油进行了测定,其中一种是由菜籽油假冒的花生油,另一种为掺入花生精油的棕榈油。     

超声辅助分散液液微萃取-柱切换离子色谱法测定食用油中胆碱的含量

移取食用油样品5.00mL,加入3mol·L~(-1) HCl溶液100μL,在60℃下进行水解反应100min,将水解后的样品溶液在80℃水浴中进行超声辅助分散液液微萃取6min,乳浊液形成后以10 000转·min~(-1)转速离心10min,弃去上层油相,吸取下层水相,用0.45μm滤膜过滤,然后进行柱切换离子色谱分析,以Dionex IonPac CS12A阳离子交换色谱柱(250mm×4mm)及Dionex IonPac CG12A阳离子保护柱(50mm×4mm)为分离柱,以12mmol·L~(-1)甲烷磺酸溶液作为淋洗液,抑制型电导检测器检测。大豆油、花生油和亚麻籽油中胆碱的质量浓度均在0.02～2.50mg·L~(-1)内与对应的峰面积呈线性关系,检出限(3S/N)在1.58～1.99μg·L~(-1)之间。方法用于测定大豆油、花生油和亚麻籽油中的胆碱,测定值的日内和日间相对标准偏差(n=5)均小于7.0%,加标回收率在72.0%～98.0%之间。     

实时直接分析-四极杆飞行时间质谱法快速鉴别油茶籽油真伪

建立了实时直接分析-四极杆飞行时间质谱(DART-QTOF-MS)技术结合化学计量学分析快速鉴别油茶籽油的方法。4种食用油(油茶籽油、菜籽油、花生油和大豆油)用甲醇-异丙醇(50∶50,含5 mmol/L乙酸铵)稀释后经实时直接分析离子源解吸电离,在正离子模式下以TOF MS和信息依赖采集模式获得质谱数据,对4种食用油的质谱图进行了初步鉴定,并采用化学计量学建立主成分分析(PCA)和正交偏最小二乘法-判别分析(OPLS-DA)模型,以实现数据可视化和油茶籽油的快速鉴别。结果表明,4种食用油的质谱图存在明显差异,主要为甘油三酯(TAG)氨加合离子［TAG+NH4］+(m/z 850~1 100)、甘油二酯(DAG)氨加合离子［DAG+NH4］+(m/z 600~700)和DART源内碎片离子,共检出20种甘油三酯和6种甘油二酯。进一步采用化学计量学对4种植物油指纹图谱进行分析,发现该方法可准确鉴别和预测油茶籽油、菜籽油、花生油和大豆油,具有前处理简单、分析速度快、操作方便和准确可靠等优点,可用于油茶籽油的鉴别研究。     

花生油存在下胆固醇氧化产物研究

探讨了温度、加热时间、花生油的量对胆固溶氧化的影响情况。用毛细管气相色谱法检出6种胆固溶氧化物。在一定范围内，氧化产物的组成和含量随加热温度升高和加热时间延长明显增加，而随着花生油量增加有明显减小的趋势。     

造纸白泥催化花生油与甲醇酯交换的特性研究

从催化剂用量、酯交换温度及时间、醇油物质的量比等影响因素出发,并借助热重、X射线荧光光谱、X射线衍射、氮气吸附与哈米特指示剂等催化剂表征手段,研究造纸白泥催化花生油与甲醇的酯交换特性.造纸白泥通过800 ℃煅烧-常温水合-600 ℃活化处理后,成分以CaO为主、比表面积为7.28 m²/g、碱性强度为9.8相似文献   

浅说复杂环境下的化学结构和反应

<正>取3个玻璃杯,倒上水。分别加入1小勺花生油、蔗糖、食盐后摇晃几下,第一个杯子的水表面出现一个个小油珠,而第二、三杯子里的蔗糖和食盐则慢慢被溶解,见图1。常识告诉我们,由于水油不混溶,所以油在水中尽量保持自己原来的形态。蔗糖呢?晶体结构被水拆散,但单个的蔗糖分子结构依然不变。最可怜的是食盐,晶体结构被肢解后变成了在水中游荡的氯离子和钠离子。就是说,作为溶剂,水可能对溶质分子的结构产生巨大     

离子色谱法测定“地沟油”中钠离子和氯离子的含量及其比例关系

采用离子色谱法测定“地沟油”样品中钠离子和氯离子的含量,通过计算两者的比例关系确定样品中是否含有“地沟油”。使用去离子水提取“地沟油”样品中钠离子和氯离子。氯离子以20 nmol/L KOH溶液为淋洗液,AS19分离柱(250 mm×4 mm)分离,抑制器电流112 mA;钠离子以20 nmol/L甲基磺酸(MSA)为淋洗液,CS12分离柱(250 mm×4 mm)分离,抑制器电流59 mA;两者分离采用的其他相同色谱条件为: 柱温、检测器温度30 ℃,电导检测器检测,进样量25 μL,流量1 mL/min,峰面积定量。氯离子的检出限为0.005 mg/L,在0～5 mg/L范围内有良好的线性关系（r2=0.999988）;钠离子的检出限为0.001 mg/L,在0～5 mg/L范围内有良好的线性关系（r2=0.999926）。氯离子平均加标回收率为94.2%,相对标准偏差(RSD)为2.4%;钠离子平均加标回收率为92.5%, RSD为2.7%。经测定、计算,正常食用油中钠离子和氯离子的物质的量比约为1,而“地沟油”中钠离子与氯离子的物质的量比高于4。“地沟油”中钠离子和氯离子的含量及其比例关系可作为判断“地沟油”的重要依据。     

傅里叶变换红外吸收光谱识别五种植物油的研究

以花生油、大豆油、芝麻油、棉籽油和米糠油为样品,采用傅里叶变换红外光谱仪,采集傅里叶变换红外吸收光谱,对光谱预处理后,提取红外特征信息,以1746cm-1和2855cm-1处的吸收峰面积比值为横坐标,1099cm-1处与1119cm-1处的吸收峰面积比为纵坐标,在Origin6.0上做出二维分布图,对各种油脂进行识别分析。结果显示,大豆油与其它4种油脂之间有明显区分;大豆油、花生油和芝麻油分布效果好,但棉籽油各样品点之间比较分散;能与其它油脂区分开的有以下几种分布花生油明显区别于芝麻油、棉籽油和大豆油;米糠油明显区别于棉籽油和大豆油。分布有交叉的油脂有米糠油与花生油或芝麻油有交叉,棉籽油与芝麻油有交叉。     

Analysis of olive oil and seed oil triglycerides by capillary gas chromatography as a tool for the detection of the adulteration of olive oil

Individual triglyceride (TG) species of olive oil and several seed oils (corn, cottonseed, palm, peanut, soybean, and sunflower) are baseline separated on a WCOT TAP CB fused-silica capillary column by capillary gas chromatography (CGC) with a flame-ionization detector (FID) and either cold on-column or split injection. An adulteration of olive oil with a low content (< 5%) of these seed oils (except peanut oil) can be verified by the detection of the increasing levels of trilinolein or tripalmitin in olive oil in which these TG species are normally absent or present at very low levels (< 0.5%). An adulteration with over 20% peanut oil can be detected by the increasing levels of palmitodilinolein. TG species that can be coeluted with trilinolein in the reversed-phase high-performance liquid chromatographic (RP-HPLC) mode are baseline separated by the CGC technique, and their structures are identified by selective ion monitoring mass spectrometry. The following comparisons--the CGC-FID and RP-HPLC methods for detection of adulteration, cold on-column and split-injection modes for CGC-FID, and silylation or thin-layer chromatography pretreatment and simple dilution of one or more of the oil samples--are also presented. The normalized percentage area of the TG species is sufficient for the method limits used in this study. Mixtures of virgin olive oil with refined or residue olive oil could not be distinguished from the virgin type by the method used in this study.     

Characterization and quantification of triacylglycerols in peanut oil by off‐line comprehensive two‐dimensional liquid chromatography coupled with atmospheric pressure chemical ionization mass spectrometry

The complexity of natural triacylglycerols (TAGs) in various edible oils is prodigious due to the hundreds of set is of TAG compositions, which makes the identification of TAGs quite difficult. In this investigation, the off‐line 2D system coupling of nonaqueous RP and silver‐ion HPLC with atmospheric pressure chemical ionization MS detection has been applied to the identification and quantification of TAGs in peanut oil. The method was successful in the separation of a high number of TAG solutes, and the TAG structures were evaluated by analyzing their atmospheric pressure chemical ionization mass spectra information. HPLC and MS conditions have been optimized and the fragmentation mechanisms of isomers have been validated. In addition, an internal standard approach has been developed for TAG quantification. Then this system was applied in peanut oil samples and there was a total of 48 TAGs including regioisomers that have been determined and quantified.     

Synchronous fluorescence spectroscopy for quantitative determination of virgin olive oil adulteration with sunflower oil

Adulteration of extra virgin olive oil with sunflower oil is a major issue for the olive oil industry. In this paper, the potential of total synchronous fluorescence (TSyF) spectra to differentiate virgin olive oil from sunflower oil and synchronous fluorescence (SyF) spectra combined with multivariate analysis to assess the adulteration of virgin olive oil are demonstrated. TSyF spectra were acquired by varying the excitation wavelength in the region 270–720 nm and the wavelength interval (Δλ) in the region from 20 to 120 nm. TSyF contour plots for sunflower, in contrast to virgin olive oil, show a fluorescence region in the excitation wavelength range 325–385 nm. Fifteen different virgin olive oil samples were adulterated with sunflower oil at varying levels (0.5–95%) resulting in one hundred and thirty six mixtures. The partial least-squares regression model was used for quantification of the adulteration using wavelength intervals of 20 and 80 nm. This technique is useful for detection of sunflower oil in virgin olive oil at levels down to 3.4% (w/v) in just two and a half minutes using an 80-nm wavelength interval.     

傅里叶变换红外光谱法对掺假橄榄油的快速鉴别

利用衰减全反射傅里叶红外光谱法对掺假橄榄油进行了快速鉴别研究。对掺入转基因大豆油、非转基因大豆油、花生油、玉米油、葵花籽油、调和油等的橄榄油采用160℃高温加热8h处理,通过观察样品加热前、后二阶导数光谱在988cm-1处特征吸收峰的吸光度变化,准确鉴别橄榄油是否掺假。该方法操作简便、前处理无需有机试剂,可作为市场筛查掺假橄榄油的快速鉴别方法。     

Abraham model correlations describing the solubilising ability of peanut oil

Experimental data have been compiled from the published literature for the logarithm of the gas-to-peanut oil partition coefficient, log K, and for the logarithm of the water-to-peanut oil partition coefficient, log P, for a series of 93 solutes having a wide range of solute polarities and hydrogen-bonding character. The two sets of partition coefficients were correlated with the Abraham solvation parameter model. The derived Abraham model correlations described the experimental log K and log P values within standard deviations of 0.13 and 0.14 log units, respectively. Principal component analysis was used to compare the solvent properties of peanut oil to four other natural oils (olive oil, soybean oil, triolein and oleyl alcohol). Peanut oil was found to be close to olive oil and soybean oil, and quite far away from triolein and oleyl alcohol.     

Simultaneous gas chromatographic determination of pirimiphos-methyl and malathion residues in peanuts,peanut hulls,peanut meats,and peanut oil

A gas chromatographic method developed for the simultaneous determination of residues of pirimiphos-methyl (O-[2-(dimethyl-amino)-6-methyl-4-pyrimidinyl] O,O-dimethyl phosphorothioate) and malathion (diethyl mercaptosuccinate S-ester with O,O-dimethyl phosphorodithioate), in whole peanuts, peanut hulls, peanut meats, and peanut oil gives good recoveries and has a limit of detection for pirimiphos-methyl and malathion of 0.04 ppm. Quantitative analysis for the two insecticides with electronic integration was reliable to 0.1 ppm.     

Preparation,oil adsorption behavior,and mechanism of micro/nanofibrous polycaprolactone membrane prepared through solution blow spinning

In this paper, biodegradable polycaprolactone (PCL) was used as the raw material to prepare micro/nanofibrous polycaprolactone membrane (PCLM) through solution blow spinning (SBS) technology. The effects of spinning conditions (distance, gas pressure, and spinning solution concentration) on PCLM structures were investigated. The obtained membranes were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, water contact angle, and thermogravimetric analysis instrument. The oil adsorbency and reusability of PCLM were measured. The oil adsorption capacity of PCLM for motor oil, peanut oil, and diesel oil was 15.93, 14.81, and 12.86 g·g^?1, respectively. After 10 times of reuse, the adsorption capacity for motor oil, peanut oil, and diesel oil could still remain at about 80% of the first cycle. The kinetic and thermodynamic studies showed that the adsorption conformed to the first‐order kinetic model and Freundlich model. Thermodynamic parameters for oil adsorption ΔG^θ, ΔH^θ, and ΔS^θ indicated the oil adsorption of PCLM was a spontaneous and physisorption process.