采用LC/MS/MS测定侧流卷烟烟气中挥发性羰基化合物的方法研究

挥发性羰基化合物是卷烟烟气中的一类重要有害物质,准确测定卷烟烟气中,特别是侧流卷烟烟气中的挥发性羰基化合物还有许多问题有待解决。实验中采用2,4-二硝基苯肼（DNPH）酸性溶液捕集侧流烟气中的羰基化合物,乙腈水溶液稀释后,以对羟基苯甲酸丁酯为内标物,用带有负离子电喷雾的LC/MS/MS定量分析侧流烟气中8种挥发性羰基化合物。实验证明,此方法有较好的重复性:对8种羰基化合物测定的相对标准偏差在6%以下;具有较高的灵敏度:8种挥发性羰基化合物的检出限均低于2.8 ng/ cig;较高的准确性:8种挥发性羰基化合物的回收率在87.2%～104.7%之间。与以往的分析方法相比,该方法具有更高的选择性,实现了烟气中巴豆醛、2-丁酮的DNPH衍生物的同分异构体的分离,对巴豆醛、2-丁酮定量更为准确,分析方法的灵敏度也明显提高。      

Determination of malachite green and crystal violet in processed fish products

This paper presents analysis of malachite green (MG) and crystal violet (CV) residues in processed fish products. Samples were homogenized and extracted with ammonium acetate buffer and acetonitrile. The extracted residues were partitioned into dichloromethane, in situ oxidized to chromic forms with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, and cleaned up on neutral alumina and propylsulfonic acid cation-exchange solid-phase extraction (SPE) cartridges. MG and CV were determined at 618 and 588 nm using HPLC with a visible detector (LC–VIS) and confirmed by LC–electrospray ionization tandem mass spectrometry (LC–ESI–MS/MS). The recoveries were as follows: MG (74.8–83.8%), LMG (80.0–88.4%), CV (68.6–73.9%), and LCV (85.5–90.0%). The method modified in this study has been evaluated by application in-house to a survey of 253 processed fish products. As a result of monitoring, MG and CV were positive in one shrimp and one eel sample, respectively. Our results showed that regular monitoring of these antibiotic residues is recommended for protection of public health.     

Improved method for the determination of 12 non-nutritive sweeteners and monitoring in various foods using liquid chromatography–tandem mass spectrometry

An improved and highly sensitive method was developed and validated for the determination of 12 (7 permitted and 5 non-permitted in Korea) non-nutritive sweeteners in various foods using liquid chromatography-electrospray ionisation-tandem mass spectrometry. The chromatographic separation was performed on an Xbridge BEH C18 column (3 mm × 100 mm, 2.5 μm) with gradient elution using 10 mM ammonium acetate in water and 10 mM ammonium acetate in methanol. Sample preparation consisted of simple dilution, homogenisation, centrifugation and purification with a C18 cartridge prior to analysis. The relative matrix effect (%ME) was within ±20% for all sweeteners. The method also showed good linearity (R² > 0.99). The limit of detection and limit of quantification values in sample were in the range of 0.02–2.66 and 0.06–8.05 mg kg^?1, respectively. The recoveries at three concentration levels ranged between 80% and 119%, with relative standard deviation values below 10%. In addition, the expanded uncertainties determined for 12 sweeteners in 5 different food matrices were confirmed to be <14%. Finally, the method was successfully applied to the analysis of sweeteners in 681 food samples purchased in Korea, Australia and Turkey. These results demonstrate that the method is suitable for the simultaneous determination of multiple-sweeteners in a variety of foods.     

Degradation Kinetics of Jujuboside a by Rat Intestinal Flora and Identification of the Metabolites by HPLC-Ms/Ms

Jujuboside A (JuA) is a representative saponin with significant sedative and hypnotic effects. Up to now, there were many arguments on its metabolic mechanism. In this study, a high performance liquid chromatography-tandem mass spectrometry (MS/MS) method was developed for investigating the degradation characteristics of JuA incubated with rat feces. With the method, the degradation kinetics of JuA was studied. The results showed JuA decomposed rapidly. It could decompose nearly 100% in only 4–6 h. The degradation regularity was consistent with the first dynamic process. In addition, seven metabolites were determined and identified to be the serial hydrolysis products of JuA. The results revealed that gastrointestinal microbiota played an indispensable role in the metabolic process of JuA. JuA may be a supplier of sugars under the hydrolysis effect induced by the bacterial enzymes. At the same time, its aglycone was produced as a by-product, which could be easier to be absorbed into the body to perform its specific bioactivities.     

Survey on acrylamide in roasted coffee and barley and in potato crisps sold in Italy by a LC–MS/MS method

ABSTRACT

A survey on the occurrence of acrylamide (AA) in roasted coffee, barley, and potato crisps was carried out using an intra-lab validated liquid chromatography (LC)–MS (mass spectrometry)/MS method. Over the years 2015–2016, 66 samples of coffee, 22 of roasted barley, and 22 of potato crisps were collected from retail outlets in Italy. AA was detected in almost all samples. In roasted coffee, the level exceeded 450 µg kg^?1, the limit recommended by the European Commission (EC), in 36.4% of the samples. In roasted barley, mean contamination was slightly lower than in coffee and no sample exceeded the EC limit of 2000 µg kg^?1. The AA contamination in potato crisps was remarkable. A percentage of 36.4 (n = 8) showed a value higher than the EC limit of 1000 µg kg^?1. Considering the average consumption of coffee and potato crisps by Italian people, AA exposure is significant and should be decreased.     

长柄扁桃加工产品中苦杏仁苷及其降解产物野黑樱苷质谱定性和定量分析

建立了长柄扁桃加工产品中苦杏仁苷及其降解产物野黑樱苷的定性和定量分析方法。长柄扁桃饼(粕)、长柄扁桃油样品经甲醇超声萃取后,采用HPLC-Q-TOF,经C18柱(100 mm×2. 1mm,2. 7μm)分离进行定性分析;采用UPLC-TSQ,在C18柱(100 mm×2. 1 mm,1. 7μm),电喷雾ESI源,正离子模式条件下进行定量分析。结果表明:建立的定性方法,经相对保留时间、精确相对分子质量和二级碎片比对,鉴定出苦杏仁苷及其降解产物野黑樱苷;建立的定量方法对于饼粕、油脂样品中苦杏仁苷和野黑樱苷线性范围分别为50～1 000 ng/m L,50～800 ng/m L;对于饼粕样品苦杏仁苷、野黑樱苷平均加标回收率分别为99. 2%～100. 5%和102. 0%～105. 8%,精密度分别为0. 1%～3. 3%和1. 6%～3. 6%,检出限分别为2. 5、5 mg/kg;对于油脂样品苦杏仁苷、野黑樱苷平均加标回收率分别为99. 1%～108. 3%和102. 9%～108. 9%,精密度分别为1. 5%～2. 2%和1. 0%～3. 5%,检出限分别为0. 06、0. 12 mg/kg。该定量方法快速简便,为保障长柄扁桃加工产品的安全提供了技术支撑。     

液质联用技术测定茶叶中多菌灵残留

建立茶叶中多菌灵残留的高效液相色谱-串联四极杆质谱联用测定方法。该方法中样品经0.2 mol/L盐酸甲醇溶液(1∶1,υ/υ)超声提取,MCX固相萃取柱净化,以ZORBAX Eclipse XDB-C18色谱柱(3.0 mm×50 mm,1.8μm)分离,流动相为0.1%甲酸水和乙腈(梯度洗脱),电喷雾正离子MRM模式检测。该方法的检出限为1.0μg/kg,线性范围0.5μg/L～3 000μg/L,加标回收率为85.0%～96.0%,相对标准偏差为3.71%。     

Occurrence of deoxynivalenol and its 3-β-D-glucoside in wheat and maize

Deoxynivalenol-3-β-D-glucoside (D3G), a phase II plant metabolite of the mycotoxin deoxynivalenol (DON), occurs in naturally Fusarium-contaminated cereals. In order to investigate the frequency of occurrence as well as the relative and absolute concentrations of D3G in naturally infected cereals, 23 wheat samples originating from fields in Austria, Germany and Slovakia as well as 54 maize samples from Austrian fields were analysed for DON and D3G by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Both analytes were detected in all the 77 field samples. DON was found at levels from 42 to 4130 ng g^?1 (977 ± 1000 ng g^?1 on average). The D3G concentrations in all cereal samples were in the range 10–1070 ng g^?1 (216 ± 253 ng g^?1 on average), corresponding to about 5–46 mol% of their DON concentrations (15 ± 8 mol% on average).     

水果中噻虫嗪农药残留LC/MS/MS测定

目的建立一种简单、快速、灵敏的水果中噻虫嗪农药残留的液相色谱-串联质谱(liquid chromatography-mass spectrometry/mass spectrometry,LC-MS/MS)分析方法。方法称取水果样品5 g,加入乙腈20 m L在超声波振荡条件下提取,提取液使用20 mg石墨化炭黑(Carb)和60 mg N-丙基乙二胺(PSA)粉末进行分散固相萃取净化,经液相色谱质谱联用仪检测,外标法定量。结果噻虫嗪农药残留的色谱图分离效果良好,方法的检出限为0.3μg/kg,线性相关系数为0.9999,噻虫嗪在苹果、梨、桃中的添加水平为0.01、0.05、0.10 mg/kg,回收试验表明该方法平均回收率为88.9%~100.3%(n=6),相对标准偏差为1.98%~4.53%。结论该方法简单、快速、灵敏、净化效果好、回收率高,适合水果中噻虫嗪农药残留的检测和安全监控。     

HPLC测定长柄扁桃仁及饼粕中苦杏仁苷与野黑樱苷

为确保长柄扁桃仁在加工与其副产物利用过程中,更快更有效地明确降解产物中有害物质含量,本文建立了一种同时测定样品中苦杏仁苷与其降解产物野黑樱苷的高效液相色谱方法。在采用甲醇提取长柄扁桃仁、饼粕中苦杏仁苷和野黑樱苷,色谱柱Aglient ZORBAX SB-C18(5μm,4.6 mm×250 mm),流动相为20%甲醇和80%水,流速1.00 mL/min,检测波长210 nm,柱温30℃的条件下,苦杏仁苷和野黑樱苷色谱峰分离良好;苦杏仁苷浓度在0.50～300μg/m L间线性关系良好,R2=0.9999,野黑樱苷浓度在0.30～100μg/m L间线性关系良好,R2=0.9999;长柄扁桃仁提取苦杏仁苷和野黑樱苷平均加标回收率分别为87.10%～96.19%(RSD为4.64%～7.83%)和88.65%～103.10%(RSD为3.03%～7.55%);而在长柄扁桃饼粕中分别为98.32%～107.99%(RSD为1.44%～3.36%)和107.58%～117.60%(RSD为1.45%～2.26%)。本方法准确、可靠,适用于长柄扁桃仁、长柄扁桃饼粕中苦杏仁苷与野黑樱苷的测定。     

液相色谱-串联质谱法测定肠衣中克伦特罗残留量不确定度分析

对液相色谱-串联质谱法测定肠衣中克伦特罗残留量的不确定度进行分析,建立数学模型,找出影响测量不确定度的各种因素,对各个不确定度分量进行评估和计算合成。给出了液相色谱-串联质谱法测定肠衣中克伦特罗残留量的相对合成标准不确定度urel=0.034及扩展不确定度U(X)=0.03μg/kg。     

液相色谱-串联质谱法测定猪肉及组织中沙丁胺醇的含量不确定度评定

目的分析液相色谱一串联质谱法检测猪肉及组织中沙丁胺醇的不确定度,探讨各因素对检验结果的影响。方法依据JJG1059.1-2012《测量不确定度评定与表示》和CNAS-GL06《化学分析中不确定度的评估指南》规定的方法和程序,分析影响测量不确定的来源,并对各不确定度分量进行了评估。结果合成各变量的不确定度,最终得到测定结果的扩展不确定度:(11.05±0.77)μg/kg(k=2)。结论影响检测结果不确定度的主要因素为回收率和标准曲线拟合,在实际测量过程严格控制实验条件可提高检测的准确性和可靠性。     

高效液相色谱-质谱联用测定乳制品中6种四环素类抗生素

建立了乳制品中6种四环素类抗生素残留的高效液相色谱-电喷雾离子阱质谱联用测定方法。该方法采用多反应监测正离子模式，可一次对6种四环素类抗生素进行定性和定量分析。该方法的检出限0．5-4．0μg/L，测定低限牛奶0．6-4.5μ/L，乳粉为6．0-45．0μg/kg，线性范围4．0-100．0μg／L，加标回收率56．1％-104．9％，相对标准偏差为2．5％-15．0％。该法具有样品预处理简单，灵敏度高，分析时间短等优点。