Quantitative analysis of acrylamide in tea by liquid chromatography coupled with electrospray ionization tandem mass spectrometry

An effective sample preparation procedure was optimized and a liquid chromatography–tandem mass spectrometry (LC–MS/MS) was developed for the quantitative analysis of acrylamide in tea. [¹³C₃]-acrylamide was used as internal standard. Acrylamide was extracted at 25 °C for 20 min by 10 ml water followed by 10 ml acetonitrile, and then 4 g of magnesium sulfate and 0.5 g of sodium chloride were added to the above mixture under stirring thoroughly. In order to increase the response of acrylamide, 9 ml acetonitrile layer was taken and concentrated to 0.5 ml. Solid-phase extraction with an Oasis MCX cartridge was carried out for clean-up. The limit of detection (LOD) and limit of quantification (LOQ) were 1 and 5 ng/ml, respectively. The recovery efficiency of the extraction procedure ranged between 74% and 79%. The levels of acrylamide in 30 tea samples were less than 100 ng/g. Black, oolong, white and yellow tea samples had quite low acrylamide contents (<20 ng/g). Higher acrylamide levels occurred in baked, roasted, and one sun-dried green tea samples (46–94 ng/g).     

The influence of latitude on the concentration of vitamin D3 and 25-hydroxy-vitamin D3 in Australian red meat

There is little information on the vitamin D content of Australian red meat or on the possible influence of latitude on this content. To determine the content of vitamin D₃ and 25-hydroxy-vitamin D₃ (25OHD₃), lamb and beef were analysed from 34° S with LC–IT-MS. To investigate the possible influence of latitude on vitamin D in meat, the lean meat and fat from five cuts of beef were analysed from 17° S and 41° S. Lamb contained 0.10 μg vitamin D₃/100 g and 0.20 μg 25OHD₃/100 g lean meat, while beef contained 0.12 μg vitamin D₃ and 0.27 μg 25OHD₃/100 g (lean meat). Latitude had no effect on the vitamin D₃ (P = 0.21) or 25OHD₃ (P = 0.29) content of lean beef, but fat from cattle in the 17° S latitude group contained significantly higher (P < 0.01) concentrations of vitamin D₃ than fat from the 41° S group of cattle.     

正己烷提取-高效液相色谱法及其串联质谱法分别测定婴幼儿配方奶粉中维生素A、D3含量

目的 建立了正己烷提取、液相色谱和液相色谱串联质谱分别测定婴幼儿配方奶粉中维生素A(VA)和维生素D₃(VD₃)含量的方法。方法 样品中加入VD₃-d₃内标后皂化,正己烷提取,去离子水清洗正己烷提取液以去除提取液中的氢氧化钾,加入氯化钠促进水和正己烷两相分层,将洗至中性的正己烷提取液浓缩至干,甲醇定容至10 mL,取1 mL溶液用液相色谱法测定VA,剩余的9 mL定溶液浓缩至干后再用1 mL甲醇复容,液相色谱串联质谱测定VD₃。结果 VA的线性范围为0.2～6.0 μg/mL,方法检出限为30 μg/100g,方法定量限为100 μg/100g;VD₃的线性范围为0.01～0.20 μg/mL,方法检出限为0.5 μg/100g,方法定量限为1.0 μg/100g。通过质控样品验证方法准确度和精密度,测定值均在质控区间内,且批内相对标准偏差和批间相对标准偏差均小于5%。使用该方法成功通过了2020年婴幼儿配方奶粉中VA、VD₃样品能力验证考核。结论 该方法所用提取试剂少,且操作简单快捷,适用于婴幼儿配方奶粉中VA和VD₃的测定。     

A simple and rapid assay based on hot water extraction and liquid chromatography–tandem mass spectrometry for monitoring quinolone residues in bovine milk

A rapid, specific and sensitive procedure for determining residues of eight widespread used quinolone antimicrobials in bovine milk is presented. The method is based on the matrix solid-phase dispersion technique with hot water as extractant followed by LC/MS/MS. The entire sample treatment did not take more than 40 min. Hot water appeared to be an efficient extracting medium, since absolute recoveries of the analytes in milk were 77–90%. The method proved to be robust as matrix effects did not affect significantly the accuracy of the method, as evidenced by analyzing six different batches of milk. Using norfloxacin as surrogate analyte, the accuracy of the method at three different spike levels of the analytes in milk was 93–110% with RSDs not larger than 10%. On the basis of a S/N of 10, estimated LOQs of this method range from 0.3 to 1.5 ng/ml, well below the tolerance levels of quinolones in milk set by the European Union.     

同位素内标-高效液相色谱质谱法测定婴幼儿配方乳粉中维生素B6和生物素

目的建立同位素内标和高效液相色谱串联质谱法(highperformanceliquidchromatographytandem mass spectrometry, HPLC-MS/MS)同时测定婴幼儿配方乳粉中维生素B_6含量(吡哆醛、吡哆醇和吡哆胺)和B_7(生物素)的分析方法。方法样品加入同位素内标后,使用温水溶解,并用高氯酸沉淀蛋白质,上清液过滤后经HSS T3色谱柱分离,三重四极杆质谱仪检测,内标法定量。结果在最优化条件下,维生素B_6和生物素分别在1.0～100μg/L和0.10～10.0μg/L范围内线性关系良好,相关系数均大于0.998;定量限分别为10.0μg/100 g和1.0μg/100g。4种化合物的回收率为86.5%～97.9%,相对标准偏差为3.0%～6.6%。质控样品检测结果表明该方法准确可靠。结论该方法灵敏度高、净化效果好、定量准确,适用于婴幼儿配方乳粉中维生素B_6和维生素B_7的检测。     

液相色谱-串联质谱法测定发酵乳中爱德万甜的含量

目的建立液相色谱-串联质谱法(liquid chromatography tandem mass spectrometry,LC-MS-MS)测定发酵乳中爱德万甜含量的方法。方法样品经1%高氯酸水溶液超声提取,提取液通过Oasis HLB固相萃取柱净化,经Agilent Zorbax XDB C_(18)色谱柱分离,流动相0.1%甲酸水溶液和乙腈洗脱,然后采用电喷雾串联质谱进行定性和定量分析。结果爱德万甜在5~200μg/L浓度范围内线性关系良好,相关系数大于0.99,爱德万甜的检出限(S/N=3)为1.5μg/kg,定量限(S/N=10)为5.0μg/kg,在5.0~500.0μg/kg的加标范围内,回收率为92.1%~101.6%,相对标准偏差为2.57%~4.56%。结论本方法前处理简单、灵敏度高,适用于发酵乳中爱德万甜含量的测定。     

亲水作用色谱-串联质谱同时测定原料乳和液体乳中三聚氰胺和舒巴坦

建立了亲水作用色谱-串联质谱同时测定原料乳和液体乳中三聚氰胺和舒巴坦的分析方法。试样采用2%乙酸水溶液提取,经乙腈沉淀蛋白,以乙腈-乙酸铵溶液为流动相,经Acquity UPLC BEH HILIC色谱柱分离后,采用多反应监测（MRM）扫描,外标法定量。三聚氰胺定量下限为10μg/kg,加标回收率为85.4%¹02.5%,相对标准偏差为3.10%⁶.55%。舒巴坦检定量下限为1.0μg/kg,加标回收率为86.1%¹04.3%,相对标准偏差为2.35%⁵.37%。该方法前处理简便快捷,灵敏度高,回收率和重现性良好,适用于原料乳和液体乳中三聚氰胺和舒巴坦的测定。      

高效液相色谱串联质谱法快速测定牛奶中地塞米松残留量

目的建立高效液相色谱串联质谱法快速有效检测牛奶中地塞米松残留量的分析方法。方法样品经乙腈提取,正己烷萃取去除杂质后,取乙腈层旋转蒸发至近干,用20%乙腈水溶液溶解后,经C_(18)色谱柱分离,以甲醇-水(9:1,V:V)为流动相,应用高效液相色谱串联质谱仪在电喷雾负离子模式(electron spray ionization,ESI-)下采用多反应监测(multiple reaction monitoring,MRM)方式对牛奶中地塞米松进行定性及定量分析。结果地塞米松在5～100 ng/mL范围内呈良好的线性关系,方法检出限为0.19μg/kg(S/N=3),不同水平的加标回收率在85%～107.2%之间,相对标准偏差在0.84%～1.22%之间(n=3)。结论该方法具有快速、简便、准确、灵敏的特点,适用于牛奶中地塞米松残留量的分析检测,可用于日常大批量快速筛查工作,有效提高日常工作效率。     

Simultaneous determination of 22 residual steroid hormones in milk by liquid chromatography–tandem mass spectrometry

Food safety and consumers’ health are paramount; therefore, it is essential to establish a novel method to determine hormone content in milk. Herein, a novel method was developed that can simultaneously determine 22 residual steroid hormones in milk. To obtain the maximum detection sensitivity, the preparation method of sample, mass spectrometer parameters and liquid chromatography conditions were optimised. The samples were concentrated using Oasis HLB solid‐phase extraction cartridge, followed by quantification via liquid chromatography (C18 column)–tandem mass spectrometer (LC‐MS). Determination of oestrogens and glucocorticoids was conducted in negative mode, whereas androgens and progesterone were in positive multiple reaction monitoring mode. The limit of detection (LOD) and limit of quantification (LOQ) of the target compounds were 0.10–1.20 μg/kg and 0.33–3.96 μg/kg, respectively. The average extraction recoveries of 22 steroid hormones were generally high (82.6–95.3%). The proposed method can be an effective alternative to measure hormonal compounds in milk.     

Determination of tetracyclines in multi-specie animal tissues by pressurized liquid extraction and liquid chromatography–tandem mass spectrometry

A specific, sensitive and robust pressurized liquid extraction (PLE) and liquid chromatography tandem mass spectrometry (LC–MS/MS) method for determining tetracycline, chlortetracycline, oxytetracycline and doxycycline in bovine, swine, poultry and lamb muscle tissues is presented. PLE was performed using an ASE^® 200 from Dionex and water as extractant, followed by solid-phase extraction (SPE) using an Oasis HLB cartridge. The method was validated for beef, chicken, pork and lamb meat in compliance with the requirements set by Commission Decision, 2002/657/EC [Commission Decision 2002/657/EC (2002). Implementing Council Directive 96/23/EC concerning the performance of analytical methods and interpretation of results. Official Journal of European Communities, L239, 66–98. (Available at: <http://europe.eu.int>)]. The average recoveries of the different meat samples, spiked with the four tetracyclines at three levels (1, 100 and 200 μg kg⁻¹ of each tetracycline), were always higher than 89% with intraday and interday precision lower than 15% and 17%, respectively. A good linearity was established for the four tetracyclines in the range from 5 to 10,000 μg kg⁻¹ with r > 0.995. The limits of quantification (LOQs) were between 0.5 and 1 μg kg⁻¹, which are well below the tolerance levels set by the European Union. The decision limit (CCα) and the decision capability (CCβ) were in the range 101–116 and 112–130 μg kg⁻¹, respectively. Compared with previous methods, sample preparation time required for the analysis and LOQs, are reduced. The method demonstrated its successful application for the analysis of 100 meat samples. Two samples of beef and one sample of chicken out of 25 of each type tested positive while none of 25 samples of either, lamb or pork, tested positive.     

液相色谱-串联质谱法测定牛奶和奶粉中6种大环内酯类药物的残留量

建立了液相色谱串联质谱测定牛奶和奶粉中6种大环内酯类药物(螺旋霉素、吡利霉素、竹桃霉素、替米卡星、红霉素和泰乐菌素)残留量的分析方法。采用乙腈提取目标物,OasisHLB固相萃取柱净化提取液,液相色谱-串联质谱测定,外标法定量。牛奶中6种大环内酯类药物的检测低限(LOQ)为1μg/kg,奶粉的LOQ为8μg/kg。6种分析物在0～100μg/L的浓度范围内呈良好线性,线性相关系数>0.992。方法在三个水平的添加回收率在81.5%～96.1%之间,相对标准偏差在3.29%～9.96%之间。方法回收率高、重现性好,适用于牛奶、奶粉等样品中大环内酯类药物残留的定量及确证检测。     

固相萃取-超高效液相色谱串联质谱法测定母乳中的游离态双酚A

目的 建立了超高效液相色谱-串联三重四级杆质谱(UPLC-MS/MS)测定母乳中游离态双酚A(BPA)的方法.方法 BPA经甲醇-丙酮(1∶1,V/V)超声提取后,过固相萃取柱(Waters Sep-Pak NH26 cc)进行净化,甲醇-丙酮(1∶1,V/V)洗脱,经Waters ACQUITY BEH C18色谱柱(50 mm×2.1mm×1.7μm)分离,在电喷雾负离子源和多反应监测模式下进行测定,内标法定量.结果 BPA在0.1 ～20μg/L范围内线性关系良好,相关系数r2＞0.997.BPA的加标回收率为91.85％ ～ 106.75％,相对标准偏差为4.80％ ～ 15.36％,检出限为0.010 μg/L,方法定量限为0.035μg/L.结论 本方法可满足母乳中游离态双酚A含量评估的需要.     

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.     

Vitamin D2 stability in milk during processing,packaging and storage

Stability of vitamin D2 in milk was determined in vitamin D2 fortified milk. Reverse phase high pressure liquid chromatography was used to determine the vitamin D₂ loss during processing, packaging and under light. The percentage losses during pasteurization, boiling and sterilization were demonstrated to be statistically insignificant. Milk was stored for seven days in both glass and plastic bottles under refrigerated temperature, non significant loss of vitamin D₂ was observed, whereas, when stored in polyethylene pouches significant loss was observed as vitamin D₂ decreased from 596.66 to 548.04 IU. This clearly indicated that vitamin D₂ was sorbed up by polyethylene material during storage resulting in its loss. Milk samples were stored for 32 h under three different light intensities (14,852,970 and 4455 lux). Non significant loss of vitamin D₂ was observed in glass packaging, whereas significant loss was observed in polyethylene pouches. In milk fortified with both calcium and vitamin D₂, non significant effect of calcium was observed on the loss of vitamin D₂.     

液相色谱同位素稀释串联质谱法测定牛奶和奶粉中3种硝基咪唑类禁用兽药及其代谢物的残留量

目的 建立了液相色谱同位素稀释串联质谱法同时测定牛奶和奶粉中3种硝基咪唑类禁用兽药(甲硝哒唑、二甲硝咪唑和罗硝哒唑)及其代谢物(羟基甲硝唑和1-甲基-2-羟甲基-5-硝基咪唑)残留量的方法.方法 采用乙腈沉淀样品蛋白,乙酸乙酯提取目标物,强阳离子交换固相萃取柱净化提取液,液相色谱-串联质谱测定,同位素内标法定量.结果 牛奶样品中5种分析物的检测限( LOQ)为0.5～1 μg/kg,奶粉样品中5种分析物的LOQ为2.5 ～5μg/kg.5种分析物在0～50 μg/L的浓度范围内呈良好线性,线性相关系数＞0.995.方法在3个水平的添加回收率在88.3％ ～ 104.4％之间,相对标准偏差在3.67％～8.52％之间.结论 方法采用同位素稀释法定量,回收率高、重现性好,适用于牛奶、奶粉等样品中硝基咪唑类药物残留的定量及确证检测.     

离子色谱串联质谱法测定婴幼儿配方奶粉中氯酸盐和高氯酸盐

目的建立离子色谱串联质谱法(ion chromatography tandem mass spectrometry, IC-MS/MS)检测婴幼儿配方奶粉中氯酸盐和高氯酸盐的分析方法。方法样品经提取、净化除去蛋白质及脂类物质后,采用离子色谱法分离,电喷雾串联质谱法测定,并采用氯酸盐-~(18)O_3和高氯酸盐-~(18)O_4作为同位素内标物质进行定量。结果在10min内完成了氯酸盐和高氯酸盐的分离分析。氯酸盐和高氯酸盐在低中高3个添加水平的回收率为79.7%～96.4%,相对标准偏差小于5%(n=6),氯酸盐检出限为1.0μg/kg,高氯酸盐检出限为0.3μg/kg。结论该方法准确、可靠,可同时检测婴幼儿配方奶粉中氯酸盐和高氯酸盐的含量。     

Fast determination of myo-inositol in milk powder by ultra high performance liquid chromatography coupled to tandem mass spectrometry

A simple and fast method has been developed and validated for the determination of myo  -inositol in milk powder samples, using solid–liquid extraction with water (0.01% formic acid, v/v):methanol (1:1, v/v). The determination was carried out by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC−MS/MS) using an electrospray ionisation source (ESI) in positive mode. Chromatographic separation was carried out using as mobile phase water (0.01% formic acid, v/v) and methanol in gradient mode. Data acquisition under MS/MS was achieved by applying selected reaction monitoring, using 181.0→$\to$109.0 and 181.0→$\to$81.0 for quantification and confirmation purposes, respectively. The technique provides a sensitive and selective determination of myo-inositol in the analysed samples, with a run time of 4 min. The limit of detection and quantification were 0.2 and 0.5 mg kg⁻¹, respectively. The method was applied to six fortified commercial milk powder samples containing myo-inositol amounts ranging from 290 to 2200 mg kg⁻¹.     

高效液相色谱-串联质谱法测定液体乳中氯酸盐和高氯酸盐

目的 建立高效液相色谱-串联质谱法(high performance liquid chromatography-tandem mass spectrometry,HPLC-MS/MS)测定液体乳中的氯酸盐和高氯酸盐的分析方法.方法 样品经0.2％甲酸水-甲醇(10:90,V:V)提取,HLB固相萃取柱净化.经Accl...     

超高效液相色谱串联质谱法测定牛奶中三氮脒残留

目的 本研究旨在结合超高效液相色谱－串联质谱(ultra performance liquid chromatography-tandem mass spectrometry, UPLC-MS/MS)技术,建立简便、快速的样品前处理方法,对牛奶中的痕量三氮脒残留进行检测。方法 用1%乙酸乙腈溶液振荡提取后,在-4℃条件下高速离心,取上清液旋转蒸干后,用10%乙腈水溶液复溶,用超高效液相色谱-串联质谱仪在正离子扫描及多反应监测(multiple reaction monitoring, MRM)模式下分析,外标法定量。结果 牛奶中三氮脒的检出限(limit of detection, LOD)为5 μg/kg,定量限(limit of quantification, LOQ)为15 μg/kg,在20~1000 μg/L浓度范围内线性良好,相关系数(r)为0.9993。将所研究的方法应用于实际牛奶样本中,其加标回收率在81.65%至85.49%之间,日内精密度分别在4.5%~5.5%,日间精密度在5.9%~8.2%之间。结论 本方法采用振荡提取加低温高速离心净化的前处理方法,简单快速,结合UPLC-MS/MS,可实现痕量水平残留的高灵敏度检测,适用于快速、高灵敏检测牛奶及其他动物源性食品中的三氮脒残留。     

高效液相色谱串联质谱检测食用植物油中的乙基麦芽酚

为了建立食用植物油中乙基麦芽酚检测的高效液相色谱串联质谱方法,食用植物油样品与二氯甲烷混合后,以1.5%NaOH水溶液做为提取溶剂,涡旋、离心后,用磷酸将上层提取液调至4～7,调节pH后的上清液用PLS固相萃取柱进行净化除杂。采用电喷雾电离源正离子多反应监测模式进行检测,采用溶剂匹配标准曲线外标法进行定量。结果表明：该方法在6.25～100 ng/mL质量浓度范围内线性关系良好(R²>0.999),方法定量限为25.0μg/kg,在3个加标水平下的平均回收率为82.9%～105.1%,相对标准偏差小于5%,重复性好。该方法准确、灵敏度高,能有效减少芝麻油的基质效应,适用于多种食用植物油中乙基麦芽酚的检测。