响应面优化表面活性剂协同微波提取苦瓜黄酮工艺

运用响应面法优化表面活性剂协同微波提取苦瓜黄酮工艺。选取了表面活性剂种类、表面活性剂浓度(g/L)、乙醇体积分数(%)、液料比(m L/g)等对黄酮提取具有显著影响的因素进行实验。通过单因素实验获得各个因素的最佳水平,进而运用Box-Behnken设计法建立中心组合实验。确定了苦瓜黄酮提取的最优条件为十二烷基硫酸钠(SDS)浓度0.20g/L、乙醇体积分数为82.9%、液料比为40.9∶1,该条件下黄酮提取率预测值为0.567%。验证实验结果表明,响应面法优选的苦瓜黄酮提取工艺是合理可行的。     

表面活性剂辅助萃取雪灵芝黄酮及结构初析

利用正交试验法对雪灵芝中黄酮类质的提取工艺进行优化,应用高效液相色谱法对提取样品的成分进行了初步分析。通过单因素试验分别考察表面活性剂种类、表面活性剂用量、乙醇体积分数、料液比、回流温度、回流时间对雪灵芝黄酮提取率的影响,选取适当的试验因素与水平,利用正交法设计试验,对各个因素的显著性和交互作用进行分析。结果表明:乙醇体积分数为5%,十二烷基苯磺酸钠浓度0.25%,料液比为1∶30(g/mL),提取时间30 min,提取温度70℃,此条件下黄酮提取率可达1.75%,样品经HPLC检测发现含有少量槲皮素和山奈酚,表面活性剂辅助浸提法在植物资源提取领域显示出了优良的应用前景。     

表面活性剂十二烷基硫酸钠协助超声波提取甘薯叶总黄酮

目的 探究表面活性剂十二烷基硫酸钠(sodium dodecyl sulfate, SDS)协助超声波提取甘薯叶总黄酮的最佳工艺条件。方法 以甘薯叶总黄酮提取量为考察指标, 采用Box-Behnken法进行试验设计, 对SDS质量浓度、乙醇体积分数、料液比、超声时间进行响应面优化。结果 各因素对甘薯叶总黄酮提取量的影响程度为C(料液比)>A (SDS质量浓度)>B(乙醇体积分数)>D(超声时间), 甘薯叶总黄酮最佳提取工艺参数为SDS质量浓度1.0%、乙醇体积分数81%、料液比1:50 (g:mL)、超声时间49 min, 在此条件下, 总黄酮提取量为 132.08 mg/g, 与回归模型预测值134.63 mg/g相差1.89%, 表明该模型与实际情况拟合良好。结论 利用表面活性剂十二烷基硫酸钠协同超声提取甘薯叶总黄酮的工艺方法稳定可行, 可为甘薯叶总黄酮的进一步开发利用提供参考依据。     

原子吸收法快速检测自来水中铅、铬、镉的含量

目的建立一种快速、准确测定自来水中铅、铬、镉含量的石墨炉原子吸收法。方法样品硝酸浓度为1%,基体改进剂为10 g/L磷酸二氢铵,配制铅、铬、镉混合标准溶液,仪器固定体积自动配置曲线,采用外标法定量。结果该检测方法回收率范围:铅95.2%~106.0%,铬95.8%~102.4%,镉94.7%~110.7%;相对标准偏差(relative standard deviation,RSD)范围:铅0.91%~1.33%,铬0.81%~2.07%,镉0.98%~4.45%;检出限:铅0.1μg/L,铬0.1μg/L,镉0.03μg/L;定量限:铅0.3μg/L,铬0.3μg/L,镉0.09μg/L。结论该方法快速、准确、重复性好,可用于自来水中重金属铅、铬、镉的检测。     

响应面试验优化木醋液精制中乳化液膜的制备工艺

采用乳化液膜法对酸枣壳木醋液进行脱酚,以煤油为膜溶剂,研究表面活性剂种类及体积分数、载体磷酸三丁酯(tributylphosphate,TBP)体积分数、内相NaOH溶液浓度和油内比对乳液稳定性及木醋液脱酚效果的影响,并以脱酚率为响应值,利用响应面法对乳化条件进行优化。结果表明:在表面活性剂T154体积分数8%、TBP体积分数3%、内相NaOH溶液浓度0.6 mol/L、油内比5∶4(V/V)条件下,4 500 r/min乳化20 min,所制乳液稳定性良好,木醋液脱酚率达55.31%。     

稀酸温和提取直接进样快速测定大米中镉含量的研究

建立了常温条件下利用稀酸温和提取直接进样石墨炉原子吸收光谱法快速测定大米中镉的方法。考察了粉碎粒径、硝酸浓度、提取时间、固液比例等因素的影响,优化了灰化温度和原子化温度等仪器条件,确定了大米中镉元素测定的最佳条件。结果表明,常温条件下采用稀硝酸提取大米中的镉元素,浸提率在98.5%~100%之间,加标回收率达到93.0%~100%之间,精密度小于5%,方法的检出限和定量限分别为0.016μg/L和0.048μg/L,样品处理时间可缩短至20 min内,与经典的微波消解原子吸收光谱法和微波消解ICP-MS法比较,各类大米中镉元素的测定值无显著性差异(P>0.05)。     

稀酸温和提取直接进样快速测定大米中镉含量

建立了常温条件下利用稀酸温和提取直接进样石墨炉原子吸收光谱法快速测定大米中镉的方法。考察了粉碎粒径、硝酸浓度、提取时间、固液比例等因素的影响,优化了灰化温度和原子化温度等仪器条件,确定了大米中镉元素测定的最佳条件。结果表明,常温条件下采用稀硝酸提取大米中的镉元素,浸提率在98.5%~100%之间,加标回收率达到93.0%~100%之间,精密度小于5%,方法的检出限和定量限分别为0.016μg/L和0.048μg/L,样品处理时间可缩短至20 min内,与经典的微波消解原子吸收光谱法和微波消解ICP-MS法比较,各类大米中镉元素的测定值无显著性差异(P0.05)。     

应用ICP-MS技术检测白酒容器中重金属元素迁移量的方法研究

应用ICP-MS(电感耦合等离子体质谱)技术,研究白酒容器中镉、铅两种重金属元素迁移量的检测方法。通过优化前处理方法,改善仪器调谐参数,ICP-MS更能准确、安全的测定白酒容器中重金属元素迁移量。实验方法线性关系良好(r≥0.9998),玻璃和陶瓷容器中的镉元素相对标准偏差在0%~2.3%之间,回收率在92%~112%之间;铅元素相对标准偏差在0.5%~4.3%之间,回收率在85%~108%之间。ICP-MS仪器检测镉、铅元素稳定性良好,方法准确可靠,能满足食品安全国家标准白酒包装容器中重金属迁移量的检测要求。     

混合基体改进剂-石墨炉原子吸收光谱法测定 速溶茶中的铅镉铬

目的以微波消解为前处理方式,建立一种石墨炉原子吸收光谱法测定速溶茶中微量重金属铅、铬、镉的实验方法。方法采用高压密闭微波消解仪对速溶茶进行消解,加入硝酸铵、硝酸钯等基体改进剂消除样品干扰,并优化仪器条件进行石墨炉原子法测定。结果测定速溶茶中铅、铬、镉的最佳基体改进剂分别为硝酸铵-硝酸钯混合基体改进剂、硝酸钯基体改进剂、硝酸铵-硝酸钯混合基体改进剂。在最佳实验条件下,铅、铬、镉的线性范围分别为0~80μg/L、0~40μg/L、0~2μg/L,检出限分别为0.3681μg/L、0.1268μg/L、0.0076μg/L,铅、镉、铬的标准曲线相关系数分别为0.9990、0.9978和0.9992,回收率均在98.64%~101.9%之间,样品测定相对标准偏差均小于5%。结论该方法简便、快速、准确,可作为速溶茶中铅、镉、铬快捷、可靠的检测方法。     

乳与乳制品中锡质量浓度检测方法研究

针对锡器具乳与乳制品,建立相应的锡检测方法,为食品安全检测作检测依据。用微波消解处理乳与乳制品样品,原子荧光法测定锡;通过优化还原剂浓度、载流液等实验条件,能达到比较理想的检测乳与乳制品中锡的质量浓度。结果表明,在最优实验条件下,仪器的检出限为0.060μg/L;在0~200μg/L质量浓度范围中,锡的线性相关系数均大于0.999。采用锡标准溶液及不同种类样品进行了精密度测定,结果的相对标准偏差均小于10%,加标回收率在88.7%~115%之间,回收率的RSD皆小于10%。该方法切实可行、样品前处理简单、结果稳定性好,适用乳与乳制品中锡质量浓度的检测。     

Investigation by ICP-MS of trace element levels in vegetable edible oils produced in Spain

The content of trace elements (Ag, As, Ba, Be, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, Ti, Tl and V) in edible oils (virgin olive, olive, pomace-olive, sunflower, soybean and corn) from Spain was determined, using inductively-coupled plasma-mass spectrometry (ICP-MS) after microwave digestion, employing only nitric acid in this step. The method has been validated by using both an oil reference material and recovery experiments over different oil samples, obtaining satisfactory results in all cases. Inter-day repeatabilities lower than 10% were observed for all of the analysed elements in the different kinds of oil samples. Studying the content of trace elements, in order to detect tendencies in the samples of the same type of oil, principal components analysis was used. Promising groupings were observed using a model with two principal components and retaining 75.3% of the variance.     

微波消解-电感耦合等离子体质谱法测定食用菌基质中4种重金属

目的 建立一种微波消解-电感耦合等离子质谱法(inductively coupled plasma-mass spectrometry, ICP-MS)测定食用菌基质中有害重金属砷(As)、汞(Hg)、铅(Pb)和镉(Cd)含量的方法。方法 采用硝酸和过氧化氢对食用菌基质样品进行微波消解, 消解液经稀释后用电感耦合等离子体质谱仪测定, 在线内标法定量, 采用国家标准物质土壤(GBW07427)和杨树叶(GBW07604)以及重复性试验, 并经过3个水平的加标回收试验进行验证。结果 测定的不同品种食用菌基质中的4种重金属元素的加标回收率在90.7%~105.3%之间, 相对标准偏差在0.88%~4.03%之间。结论 该方法稳定性好、灵敏度高、定量准确, 提高了检测效率, 适用于食用菌基质中As、Hg、Pb和Cd, 4种重金属快速、准确的定量分析。     

Determination of Trace Elements in Camellia Oil by Vortex-Assisted Extraction Followed by Inductively Coupled Plasma Mass Spectrometry

A simple vortex-assisted liquid–liquid extraction protocol followed by ICP-MS has been developed for the determination of nine elements (Cr, Mn, Fe, Ni, Cu, As, Zn, Cd, and Pb) in camellia oil samples. The key parameters affecting the extraction efficiency (extraction solvent characteristics, extraction time, and solvent/oil ratio) were carefully examined and optimized. Optimum results were obtained when 5 g of oil sample was used followed by vortex-assisted extraction for 20 min with 10 mL of 10 % HNO₃ (v/v). Detection limits ranging from 0.03 to 1 μg L^?1 and relative standard deviation lower than 6 % were obtained. The accuracy of the method was assessed by spiking experiments and comparison of the results from the extraction procedure with those obtained from microwave-assisted digestion of the samples. The recoveries were in the range of 84.3~102.3 %. No statistical differences, based on t test at a confidence level of 95 %, were detected. The proposed method was found to be simple, fast, and accurate when applied to camellia seed oil samples and has great potential in quantitatively detecting elements in various oils.     

Top-down技术控制图法评估电感耦合等离子体质谱法测定大米中镉含量的不确定度

采用Top-down技术控制图法评估电感耦合等离子体质谱法（ICP-MS）测定大米中镉含量的不确定度。按照GB 5009.268-2016《食品中多元素的测定》规定的分析方法[1]，在期间精密度条件下测定大米质控样中镉（Cd）的含量，采用Top-down技术原理对半年所得30组数据进行分析和评估。通过测量系统的性能检验可得出正态性的检验（As2*）和独立性检验（A2*MR）均＜1，表明99%概率下测量系统正态独立，计算得到扩展不确定度的结果为U=0.52μg/kg。Top-down技术可用于食品检验中对食用农产品检测结果不确定度的评估，该技术在建立数学模型上更简单，对测量不确定度结果的评价更灵活、方便。     

微波消解-火焰原子吸收光谱法测定油脂样品中的9种金属元素

为建立一种能对油脂样品中9种金属元素含量进行准确测定的方法,以5种食用油和2种地沟油为试材,采用微波消解法对样品进行前处理,利用火焰原子吸收光谱仪进行测定,并对微波消解油脂样品时的程序和条件进行了设计和优化,最终建立了包含5个步骤的微波消解新程序,其中最大消解压力为35 atm,最大温度为190 ℃,保持时间为20 min。方法性能考察表明:9种待测金属元素在各自的浓度范围内均具有良好的线性关系,决定系数为0.9982~0.9994,检出限为0.0013~0.0122 μg/mL,样品的加标回收率范围在98.94%~101.45%之间,RSD≤4%（n=6）。采用所建方法对7种油脂样品中的9种金属元素进行了含量测定,检测结果表明:5种食用油中含有丰富的营养元素,而Cr、Cd、Pb元素未检出,初步判断油脂的营养价值和安全性较高。而地沟油样品由于检出含有Cr、Cd、Pb,且Pb的含量远超国家标准限定值,已不适宜食用。实际应用表明:所建方法具有操作简便、准确度高等优点,能满足各类油脂中金属元素的检测需要。     

Determination of tertiary butylhydroquinone in edible vegetable oil by liquid chromatography/ion trap mass spectrometry

A simple, sensitive and accurate analytical method for quantification of tertiary butylhydroquinone (TBHQ) in edible vegetable oil was established by liquid chromatography/ion trap mass spectrometry (LC/ITMS). After extraction, 5 μl of the extracts was directly injected into LC/ITMS for TBHQ determination. Ethanol was selected as the extraction solvent. The optimized fragmentation amplitude was 1.70 V and electrospray ionization (ESI) was more suitable than atmospheric pressure chemical ionization (APCI) for TBHQ detection. The calibration curve showed good linearity (R² = 0.9990) and recoveries from spiked samples ranged from 81.9% to 110.5%. Relative standard deviations of intra-day and inter-day were in the ranges 2.5–5.7% and 3.9–13.8%, respectively. The procedure allows the detection of 0.3 mg/kg TBHQ in edible vegetable oil. Typical edible vegetable oils in the market were detected for TBHQ by the proposed method. As results, TBHQ was detected in blend oil, soybean salad oil and camellia oil samples.     

金属有机骨架基质固相分散高效液相色谱法检测食用油中苯并[a]芘

目的建立基于金属有机骨架材料(metal-organic frameworks, MOFs) MIL-101(Cr)的基质固相分散进行食用油样品前处理,并以高效液相色谱串联荧光检测器(high performance liquid chromatography-fluorescence detector, HPLC-FLD)对苯并[a]芘进行定量检测。方法吸附后将体系装填于6 mL固相萃取空柱,以丙酮洗脱,氮气吹干定容。色谱流动相为乙腈-水(80:20, V:V),流速0.3 mL/min,激发波长369 nm,发射波长404 nm,外标法定量。结果苯并[a]芘在1～50ng/g范围内呈良好线性,相关系数r~2为0.9997,加标回收率为96.0%～99.9%。方法检测限及定量限分别为0.33ng/g和1.09ng/g,实际样品检测的相对标准偏差为2.8%～8.9%。结论该方法操作简单,测定结果准确,同时克服了常规固相萃取法易堵塞、渗漏、过载及负压过高等问题,可用于食用油中苯并[a]芘的检测。     

Determination of Cd (II), Cu (II), and Pb (II) in Some Foods by FAAS after Preconcentration on Modified Silica Gels with Thiourea

Abstract: This study describes preconcentration method for determination of Cd (II), Cu (II), and Pb (II) in some food samples. Silica gel was modified with thiourea and characterized by IR and C, H, N, S elemental analysis. Modified silica gel was used as a solid phase extraction for determination of Cd (II), Cu (II) and Pb (II) in tuna fish, biscuit, black tea, rice, ka?ar cheese, honey, tomato paste, and margarine samples. The analytical conditions including eluent type, pH of sample solutions, flow rates of sample and eluent solutions, etc. were optimized. The influence of the matrix ions on the involvement of the Cd (II), Cu (II), and Pb (II) were also studied. GBW 07605 tea standard reference material was used for validation of method. The method was successfully applied for the determination of Cd (II), Cu (II), and Pb (II) ions in food samples. The detection limits were in the range of 0.81 μg/L, 0.38 μg/L, and 0.57 μg/L for cadmium, copper and lead, respectively. The relative standard deviations of the procedure were below 10%. The sorption capacities were found as 92 μmol/L Cd (II), 286 μmol/L Cu (II), and 121 μmol/L Pb (II).     

快速消解-电感耦合等离子体质谱法测定水产配合饲料中的铬、铜、锌、砷、镉、汞和铅

目的 建立快速消解-电感耦合等离子体质谱法(ICP-MS)测定水产配合饲料中的铬(Cr)、铜(Cu)、锌(Zn)、砷(As)、镉(Cd)、汞(Hg)和铅(Pb)的检测方法。方法 用硝酸将样品在聚丙烯快速消解管中消解,通过优化碰撞池气体流量及在线添加内标的方式消除干扰,同时进行了线性、准确度及精密度试验,并应用于质控样品及实际样品的检测。结果 各元素的标准曲线线性良好,相关系数为1.0000,检出限为0.00229 ~ 0.15030 mg/kg,回收率为91.8% ~ 108.2%,相对标准偏差(RSD)为1.0% ~ 7.9%,质控样品测定值在标准值范围内。在市售水产配合饲料中发现2批次Cr含量超标,需对其来源及形态进行深入分析,评估潜在的质量安全及生态安全风险。结论 建立的方法高效准确,可应用于水产配合饲料的检测分析工作。