气相色谱法测定食用油中BHA和BHT残留量的对比研究

目的建立气相色谱法测定食用油中叔丁基羟基茴香醚(butyl hydroxyanisole,BHA)和二丁基羟基甲苯(butylated hydroxytoluene,BHT)的残留量。方法使用无水乙醇萃取样品,经中性氧化铝吸附杂质,HP-5毛细管柱分离,使用气相色谱仪定量分析BHA和BHT在食用油中的残留量。同时,与GB/T 5009.30中的方法进行对比,考察了本方法的线性、重现性、回收率和精密度。结果本方法中BHA和BHT的线性范围分别为2.02~40.48 ng和2.07~41.36 ng,标准曲线方程分别为Y=16.61X+10.03(r=0.9996)和Y=20.14X+16.56(r=0.9997);BHA和BHT的检出限分别为92.4 ng/kg和108.6 ng/kg,加标回收率分别为98.94%(相对标准偏差为0.33%)、98.69%(相对标准偏差为0.34%)。结论本实验建立的方法灵敏度高、定量准确,和国标法相比,具有简单实用的特点,适合食用油中BHA和BHT残留量的检测。     

气相色谱内标法测定鱿鱼油中的胆固醇

目的:以正三十二烷为内标物,建立了鱿鱼油中胆固醇含量测定的气相色谱(GC)分析方法。方法:采用0.5mol/L的氢氧化钾乙醇溶液在65℃水浴锅中对油样皂化30min,乙醚萃取,毛细管气相色谱法测定鱿鱼油中胆固醇,讨论并确定了样品皂化的最佳条件。结果:利用该方法,胆固醇与杂质可以得到较好的分离和准确的定量。内标法制定标准曲线相关系数大于0.999,测得胆固醇含量为29.01±0.56mg/g。胆固醇的最低检出限为2.21ng,加标回收率在92.14%～102.45%之间,其RSD<5%(n=3)。结论:该法灵敏度高,分离效果好,定量准确,适用于鱿鱼油中胆固醇的含量测定。     

微生物阻抗法快速测定乳粉中的叶酸含量

为建立一种基于微生物阻抗法快速测定乳粉中叶酸含量的新方法,在GB 5009.211—2022第一法的基础上制作标准系列管,优化测定条件,探索菌体的阻抗变化与叶酸含量之间的线性关系,建立微生物阻抗法标准曲线。以乳粉质控样品和市售乳粉为试验样品,考察此方法的检测性能。结果表明：当标准系列管培养20 h,采用离心+超声破碎处理时,测定菌体的电阻率值与叶酸含量在0.000～0.100 ng/mL之间的线性关系最好。拟合出标准曲线方程为Y=8866.3X+177.38,相关性系数R2=0.9952。检出限为1.26μg/100 g,定量限为4.20μg/100 g,加标回收率为96.2%～103.6%。对乳粉质控样品和4种市售乳粉的相对标准偏差(Relative standard deviation, RSD)值在3.4%～6.4%之间,总检测时间为3 d左右。与国家标准方法相比,该方法的重复性、准确度相当,但检测时间更短,可快速测定乳粉中的叶酸含量。     

气相色谱质谱联用测定茶油中角鲨烯含量

建立茶油中角鲨烯气相色谱-质谱联用(GC-MS)的测定方法。茶油通过正己烷直接稀释,采用气相色谱-质谱(GC-MS)选择离子监测(SIM)进行分析,以三十二烷为内标,用内标标准曲线法测定了茶油中角鲨烯的含量。该内标法标准曲线的相关系数为0.999,在0.01～3.00μg/mL范围内线性关系良好,角鲨烯最低检出限为0.03ng,方法的回收率为85.0%～115.0%,相对标准偏差小于5%(n=6)。利用此方法测定广东兴宁和江西赣州两地产茶油毛油中角鲨烯含量分别为120.43μg/mL和97.05μg/mL,该法操作简便、快速,测试结果准确、可靠。     

高效液相色谱-串联质谱法测定花生中的黄曲霉毒素B1

目的建立高效液相色谱-串联质谱法测定花生中黄曲霉毒素B_1含量的分析方法。方法样品经乙腈水溶液提取,三氯甲烷反提取后,正己烷净化,以水(D)和乙腈(A)作为流动相进行梯度洗脱,质谱采用多离子检测模式对黄曲霉毒素B_1的定量离子和定性离子进行检测。结果在0.5～10 ng/mL范围内线性良好(线性方程:Y=8.57×10~3X+312, r0.999),黄曲霉毒素B_1在1、5、10μg/kg 3个水平上进行加标回收试验,平均回收率为93.2%～100.2%,相对标准偏差为2.8%～6.9%,方法检出限为0.1μg/kg。结论该方法经济、快速、准确,适合测定花生中黄曲霉毒素B_1的含量。     

北京地区部分市售食用植物油中玉米赤霉烯酮和脱氧雪腐镰刀菌烯醇的污染状况分析

目的分析北京市售植物油中玉米赤霉烯酮和脱氧雪腐镰刀菌烯醇的污染状况。方法实验采用同位素稀释-超高效液相色谱-串联质谱法,在多反应监测模式下对所采集玉米油、花生油、调和油等食用油样中的玉米赤霉烯酮(ZEN)、脱氧雪腐镰刀菌烯醇(DON)进行了检测,并对其污染现状进行分析。结果 ZEN和DON在3~500 ng/mL浓度范围内线性良好,相关系数为0.999,加标回收率为95.05%~107.10%,ZEN和DON方法的检出限分别为0.03μg/kg和0.9μg/kg;ZEN和DON方法的定量限分别为0.1μg/kg和3μg/kg。对北京市售30个油样检测结果表明,DON为未检出,ZEN检出率为100%,最高含量为333μg/kg,最低含量为1.95μg/kg,平均含量为67.7μg/kg,低于欧盟规定的限量标准400μg/kg。结论通过分析食用油中真菌毒素的含量状况,初步了解了北京市售植物油中玉米赤霉烯酮和脱氧雪腐镰刀碱烯醇的污染状况。     

液相色谱-串联质谱法检测食用油脂中多环芳烃

建立了有机溶剂萃取、硅胶固相萃取柱净化、液相色谱-串联质谱法(LC-MS/MS法)测定食用油脂中EPA 16种多环芳烃的检测方法。EPA 16种多环芳烃的定量限分别为0.02~0.43μg/kg,回收率为86.5%~104.6%,日内精密度小于6%,日间精密度小于5%。在40个受测油脂样品中,EPA 16种多环芳烃的含量范围为11.68~146.06μg/kg。对照我国GB 2716规定,所有受测样品中苯并(a)芘含量均不超过≤10μg/kg的限量标准。然而,8个油样的苯并(a)芘含量超过了欧盟≤2μg/kg的限量标准,10个油样的PAH4含量超过了欧盟≤10μg/kg的限量标准。     

顶空-气相色谱法测定食用油中苯和正己烷的残留量

采用顶空-气相色谱法测定食用油中苯和正己烷的残留量。选择顶空进样器的平衡温度和平衡时间分别为120℃和30 min;采用FID检测器,HP-5毛细管柱分离,顶空进样。重点考察了方法的线性、重复性、回收率和仪器的精密度。结果表明:苯和正己烷的线性范围分别为1.26~12.64μg、0.92~9.28μg,线性方程分别为Y=12.453X+11.15(r=0.999 6)、Y=82.56X+59.466(r=0.999 7);苯和正己烷的检出限分别为0.063 0、0.046 4μg/mL,加标回收率分别为96.2%(RSD=1.91%)、93.8%(RSD=1.63%)。该方法灵敏度高,定量准确,具有简单实用的特点,适合食用油中苯和正己烷的残留检测。     

鸡蛋中环丙沙星、恩诺沙星残留物HPLC-MS/MS分析

目的建立鸡蛋中环丙沙星、恩诺沙星残留物液相色谱-串联质谱(LC-MS/MS)检测方法。方法鸡蛋中环丙沙星、恩诺沙星用酸性乙腈提取,正己烷除脂,采用Waters ACQUITY UPLC?BEH C18色谱柱(2.1mm×100mm,1.7μm)分离,电喷雾离子源在正离子模式下电离,多反应监测(MRM)模式扫描。结果环丙沙星和恩诺沙星分别在5.194～129.85 ng/ml和2.154～53.85 ng/ml范围内线性关系良好,线性方程分别为Y=1300X+17.7(r=0.9999)、Y=1450X-658(r=0.9993)。环丙沙星和恩诺沙星定量限(S/N=10)分别为1.0388μg/kg和0.4308μg/kg。分别添加环丙沙星含量为1.0388,2.597μg/kg,恩诺沙星含量为0.4308,1.077μg/kg的对照品溶液于阴性鸡蛋基质中,回收率分别90.7%～107.6%、80.1%～101.6%和85.0%～105.4%、86.9%～103.6%。结论该方法简单、灵敏、准确,可以作为鸡蛋中环丙沙星、恩诺沙星的检测方法之一。     

高效液相色谱法测定天力通片中天麻素含量

目的建立高效液相色谱法测定天力通片中天麻素含量的方法。方法采用Waters Symmetry C18(250mm×4.6 mm,5μm)色谱柱;流动相为乙腈-0.05%磷酸溶液(1:99);检测波长220 nm;柱温25℃。结果天麻素在0.1～0.6μg范围内与峰面积呈现良好的线性关系,回归方程为Y=569 027X-9382.1(r=0.9993);天麻素的检测限与定量限分别为2.50 ng和4.20 ng;样品的加样回收率为98.70%。结论该方法灵敏、准确、线性和重现性好,适用于保健食品天力通片中天麻素的含量测定。     

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。     

Rapid and improved determination of furan in baby foods and infant formulas by headspace GC/MS

Furan is a 5-membered ring compound with high volatility. The U.S. Food and Drug Administration (FDA) has recently published a report on the occurrence of furan in a large number of thermally processed foods. However, the FDA's analytical method, using standard curve addition, is not suitable for high-throughput routine laboratory operations. We developed a rapid and improved method for determination of furan in foods by headspace GC/MS. Quantification was achieved by using an internal standard of d4-furan and an external calibration curve of furan normalized against the internal standard. The incubation temperature for equilibration was set at 60 degrees C to avoid the formation of furan during analysis. The levels of furan in baby foods and infant formulas were determined with this method. Validation data showed good precision and accuracy. The LOD and LOQ were 0.2-0.5 ng/g and 0.5-2 ng/g for various food matrixes, respectively. The level of furan detected was in the range of 1.4 to 90 ng/g in baby foods and in the range of non-detectable to 36 ng/g in infant formulas.     

应用脂肪酸甲酯快速筛选植物油中掺假地沟油

根据植物油和地沟油中脂肪酸酯存在方式的不同,建立植物油中地沟油掺假的快速筛选方法。植物油中脂肪酸是以甘油三酯的形式存在,地沟油中脂肪酸以脂肪酸甲酯的形式存在,利用气相色谱-质谱的全扫描模式,结合NIST 05标准谱库检索功能,对37 种脂肪酸甲酯进行测定。样品采用直接稀释-气相色谱-质谱全扫描分析脂肪酸甲酯,100 个植物油样品中均未检出脂肪酸甲酯;20 个地沟油样品中13 个检出肉豆蔻酸甲酯（C14∶0）、棕榈酸甲酯（C16∶0）和硬脂酸甲酯（C18∶0）等14 种脂肪酸甲酯,检出率为65%,且70%的检出脂肪酸甲酯的地沟油样品中脂肪酸甲酯种类多、含量较高。因此,若植物油样品脂肪酸甲酯种类多、含量高,则可判定为有地沟油掺假;若脂肪酸甲酯含量低或没有脂肪酸甲酯,则可以进一步用其他指标和方法进行检测,脂肪酸甲酯的检测方法可以作为地沟油掺假的快速粗筛方法。     

超低温冷冻除脂-气相色谱串联质谱法检测食用植物油中21种邻苯二甲酸酯

建立了超低温冷冻除脂-气相色谱串联质谱(GC-MS/MS)检测食用植物油中21种邻苯二甲酸酯(PAEs)的新方法。样品用乙腈提取,经超低温(-80℃)冷冻10 min除脂,再经减压浓缩,以正己烷复溶,采用GC-MS/MS多反应监测模式进行测定。结果表明,在考察浓度范围(1~1000 ng/mL)内21种PAEs均呈现良好线性,相关系数均大于0.999,检出限为0.10~8.52 μg/kg,定量限为0.32~28.40 μg/kg,加标回收率为74.31%~116.62%,相对标准偏差为1.21%~17.82%。对市售7类19个油样的抽样检测,显示邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二异丁酯(DIBP)、邻苯二甲酸二丁酯(DBP)、邻苯二甲酸丁基苄基酯(BBP)、邻苯二甲酸(2-丁氧基)乙酯(DBEP)、邻苯二甲酸二正庚酯(DHP)、邻苯二甲酸二(2-乙基己)酯(DEHP)和邻苯二甲酸二正辛酯(DNOP)共9种PAEs被检出,其中DMP、DBP、DBEP、DHP和DEHP检出率均大于90%,含量范围为105.57~2156.76 μg/kg。该方法操作简便,成本低,可用于食用植物油中PAEs的有效测定。     

LC-MS/MS法测定食用油中的辣椒素和二氢辣椒素

建立了用氨基固相萃取小柱净化提取液,液相色谱串联质谱（LC-MS/MS）法测定食用油中辣椒素和二氢辣椒素含量的检测方法。结果表明,辣椒素在0～100 ng/mL范围内线性关系良好（R2 = 0.998 6）,平均回收率在70.6%～90.5%,相对标准偏差（RSD,n=3）在3.1%～8.9%,检出限为0.03 μg/kg;二氢辣椒素在0～20 ng/mL范围内线性关系良好（R2 = 0.998 8）,平均回收率在71.5%～100.7%,相对标准偏差（RSD,n=3）在6.0%～13.2%,检出限为0.006 μg/kg。该方法简便快速、准确可靠,是鉴别地沟油和测定食用油中辣椒素类物质的有效方法。     

QuEChERS净化—气相色谱—质谱法测定食用植物油中4种合成抗氧化剂

建立了一种QuEChERS净化—气相色谱—质谱(GC-MS)快速测定7类食用植物油中4种合成抗氧化剂(BHT、BHA、TBHQ、Ionox-100)的方法。样品经乙腈超声提取后,运用QuEChERS技术净化,采用DB-35MS毛细管色谱柱(30 m×0.250 mm×0.25μm)分离,选择离子监测(SIM)模式进行测定,外标法定量。结果表明:各合成抗氧化剂在0.5~20.0μg/mL内线性关系良好,其相关系数R 2均>0.999,相对标准偏差RSD为0.4%~4.5%,检出限为0.05 mg/kg,加标回收率为84.1%~108.0%,采用质控样品进行验证,结果均为满意。该方法适用于食用植物油中抗氧化剂含量的快速筛查和测定。     

Multiclass mycotoxin analysis in edible oils using a simple solvent extraction method and liquid chromatography with tandem mass spectrometry

ABSTRACT

A simple and rapid method for the simultaneous determination of 11 mycotoxins – aflatoxins B₁, B₂, G₁ and G₂; fumonisins B₁, B₂ and B₃; ochratoxin A; zearalenone; deoxynivalenol; and T-2 toxin – in edible oils was established using liquid chromatography tandem mass spectrometry (LC-MS/MS). In this study, QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe), QuEChERS with dispersive liquid–liquid microextraction, and solvent extraction were examined for sample preparation. Among these methods, solvent extraction with a mixture of formic acid/acetonitrile (5/95, v/v) successfully extracted all target mycotoxins. Subsequently, a defatting process using n-hexane was employed to remove the fats present in the edible oil samples. Mass spectrometry was carried out using electrospray ionisation in polarity switching mode with multiple reaction monitoring. The developed LC-MS/MS method was validated by assessing the specificity, linearity, recovery, limit of quantification (LOQ), accuracy and precision with reference to Commission Regulation (EC) 401/2006. Mycotoxin recoveries of 51.6–82.8% were achieved in addition to LOQs ranging from 0.025 ng/g to 1 ng/g. The edible oils proved to be relatively uncomplicated matrices and the developed method was applied to 9 edible oil samples, including soybean oil, corn oil and rice bran oil, to evaluate potential mycotoxin contamination. The levels of detection were significantly lower than the international regulatory standards. Therefore, we expect that our developed method, based on simple, two-step sample preparation process, will be suitable for the large-scale screening of mycotoxin contamination in edible oils.     

基于主成分分析法评价两种餐饮用油的煎炸性能

目的 分析两种常见餐饮用油(餐饮调和油A和餐饮调和油B)煎炸性能的差异,并对餐饮用油煎炸品质进行综合评估。方法 在模拟西式快餐实际油炸条件下进行煎炸薯条实验,考察了餐饮用油在油炸过程中十项品质指标,并利用主成分分析法(PCA)对两种餐饮用油在油炸过程中的煎炸性能进行综合评价。结果 餐饮用油品质指标间存在不同程度的相关性,PCA将10个品质指标缩减成2个综合性评价指标,累计贡献率达87.920%,反映了餐饮用油煎炸品质的大部分信息,并进一步提取出评估餐饮用油煎炸性能的5个关键指标,即过氧化值、极性组分、碘价、羰基值以及亚油酸/棕榈酸比值。主成分分析综合得分表明,在油炸过程中,餐饮调和油A得分较高,具有较好的煎炸性能。结论 本研究建立的餐饮用油煎炸性能评价体系为煎炸油的筛选和质量控制提供借鉴。     

Formation of trans fatty acids in edible oils during the frying and heating process

To assess an impact of heated edible oils on intake of trans fat, the formations of trans fatty acids (TFAs) in cooking conditions was estimated by a frying and heating model system. For the frying model, sliced raw potatoes (10% of the frying oil (w/w)) were fried in commercially available canola oil at 160, 180 and 200 °C, and the 10 frying cycles were performed. The TFAs contained both in fried potatoes and in frying oils were measured by gas chromatography (GC). Lipids content of raw potatoes was about 0.1% (w/w) and TFAs in the raw potatoes were negligible. On the other hand, fried potatoes contained lipids at the level of 8.8%–9.2% and their fatty acid composition was mostly in correspondence with that of the frying oil. The TFAs amount of potatoes fried by the tenth frying operation was at the level of 0.99–1.05 g/100 g lipids. When 100 g potatoes fried in this process were consumed, the TFAs intake was estimated at less than 0.1 g. After 10 frying operations, TFAs content, acid values and peroxide values of the frying oils were measured and compared with those of corresponding heated canola oils without food. The amounts of trans 18:1 FAs contained both in the frying oil and in heated oil were less than the quantitative limit (0.047 g/100 g oil). The increases of trans 18:2 FAs and trans 18:3 FAs of the used frying oil were 0.02 g/100 and 0.05 g/100 g, respectively, compared with those of the fresh oil. trans 18:2 FAs accumulation in the heated oil was slightly less than that in the frying oil. To elucidate TFAs accumulation in various edible oils during cooking, six kinds of commercially available edible vegetable oils were heated to 180 °C in glass test tubes. Small changes in TFAs amounts were observed after four hours heating. These results suggested that an ordinary frying process using unhydrogenated edible oils has little impact on TFAs intake from edible oils.     

一株塔宾曲霉的分离鉴定及其在地沟油鉴别中的应用

为了研究微生物在地沟油鉴别领域的应用,采用地沟油精炼技术对地沟油进行精炼,并从地沟油中分离获得8株真菌,其中发现菌株DGY03能够在地沟油培养基上快速生长繁殖,对其进行形态学观察以及采用分子生物学等方法进行鉴定。同时进一步探讨了菌株DGY03应用于地沟油鉴别领域的可行性,观察并比较其在地沟油和四种食用油培养基上的菌落生长速度、菌落长势以及培养基颜色变化等特征。结果表明,该菌株的菌落形态和显微结构与曲霉属基本相同,其ITS序列与Aspergillus tubingensis的同源性达100%,确定该菌株为塔宾曲霉(Genbank登录号:MF186869)。菌株DGY03在地沟油培养基上的菌落生长速度和菌落长势明显优于其它四种食用油培养基,其在地沟油培养基上的菌落生长速度为0.64 cm/d,而在大豆油、菜籽油、玉米油、花生油培养基上的菌落生长速度分别为0.21、0.28、0.24、0.29 cm/d。由此初步推断,利用菌株DGY03作为指示菌鉴别地沟油是可行的。