LC-MS/MS法检测牛奶中14种β-内酰胺类抗生素残留

采用超高效液相色谱串联质谱建立了牛奶中14种β-内酰胺类抗生素残留检测方法。样品经过乙腈提取、氮吹、HLB柱净化后,经Acquity UPLC BEH Shield RP18(100 mm×2.1 mm,1.7μm)分离,以乙腈和体积分数0.02%甲酸溶液为流动相进行梯度洗脱,14种化合物在8 min内分离效果良好。方法的定量限均低于2.5μg/L,在2.5~250μg/L范围内线性良好,相关系数均在0.99以上;通过2,10,100μg/L 3个浓度的加标回收实验表明,回收率为73.2%~109.8%,RSD%为1.5%~12%,方法满足牛奶中β-内酰胺类抗生素药物残留检测要求。     

超高效液相色谱-四极杆-飞行时间质谱法快速筛查牛奶中的农药和兽药残留

利用超高效液相色谱-四极杆-飞行时间质谱(UPLC-Q-TOF-MS)技术建立了牛奶中42种农药和兽药残留的快速检测方法。目标药物包括常用的13种农药和29种兽药,采用QuEChERS（Quick, Easy, Cheap, Effective, Rugged, and Safe）方法进行样品前处理。牛奶样品经含1%甲酸的乙腈溶液提取,同时加入无水硫酸钠和氯化钾盐析,提取液经C18填料净化后直接测定。目标药物经ACQUITY UPLCTMBEH C18柱分离,以乙腈和0.1%甲酸水溶液为流动相进行梯度洗脱,采用正离子全信息串联质谱扫描模式(MSE)进行检测。结果表明,牛奶中42种农药和兽药的定量限(LOQ, S/N=10)为1～100 μg/kg; 3个加标水平的平均回收率为68.2%～129.1%,相对标准偏差为2.8%～30.8%。该方法快速简便、灵敏度较高,可用于牛奶中42种农兽药的快速筛查。     

亲水色谱-串联质谱法对牛奶与奶粉中三聚氰胺及其衍生物含量的测定

建立了牛奶和奶粉中三聚氰胺及其3种衍生物（三聚氰酸、三聚氰酸一酰胺、三聚氰酸二酰胺）的亲水色谱-串联质谱检测方法（HILIC-MS/MS）。牛奶样品直接用乙腈超声波提取;奶粉样品先用水溶解后再加乙腈超声波提取,高速离心后以乙腈-水为流动相,采用亲水作用色谱柱分离这4种化合物,在电喷雾正、负电离切换多反应监测模式下进行定性与定量分析,三聚氰酸一酰胺与三聚氰酸二酰胺含量在50～10000μg/kg之间、三聚氰胺与三聚氰酸在25～5000μg/kg之间,均获得良好的线性。方法检出限（LOD）为5～20μg/kg,定量下限（LOQ）为50～100μg/kg,3个添加水平的平均回收率为81%～97%。该方法简便、快速、准确,可满足牛奶及奶粉中三聚氰胺、三聚氰酸、三聚氰酸一酰胺、三聚氰酸二酰胺测定的需要。     

超高效液相色谱-串联质谱法测定牛奶和奶粉中6种聚醚类抗生素残留量

建立了用于检测牛奶和奶粉中拉沙洛菌素、莫能菌素、尼日利亚菌素、盐霉素、甲基盐霉素和马杜霉素铵6种聚醚类抗生素残留量的超高效液相色谱-串联质谱分析方法.用乙腈提取样品中的聚醚类抗生素,提取液经HLB固相萃取柱净化,采用超高效液相色谱分离,以电喷雾离子源正离子多反应监测模式进行质谱分析.6种抗生素在0.5～100.0 μg/L范围内均呈线性,相关系数r>0.99.在空白样品中添加6种聚醚类抗生素的回收率均在74.0%～98.5%之间; 精密度(RSD)4.8%～17.2%.牛奶中6种聚醚类抗生素检出限均为0.2 μg/L;奶粉中6种聚醚类抗生素检出限均为1.6 μg/kg.     

超高压液相色谱-串联四极杆质谱法对牛奶中24种磺胺类药物残留的检测

利用超高压液相色谱-电喷雾串联四极杆质谱（UPLC-MS/MS）联用技术,建立了一种能在10 min内快速分离和测定牛奶中24种磺胺类药物残留的方法。样品经匀浆、超声、乙腈重复提取、氮吹浓缩,流动相溶解,饱和正己烷脱脂。采用ACQUITY UPLCTMBEHC18柱（100 mm×2.1 mm i.d.,1.7μm）,以乙腈-0.2%乙酸水溶液（体积比1∶9）为流动相,梯度洗脱,目标分析物使用超高压液相色谱-电喷雾串联质谱进行测定;以保留时间和离子对进行定性和定量,在ESI（＋）和MRM监测模式下进行样品分析。该方法检出限（LOD）为0.04～1.35μg/kg;在1～200μg/L范围内线性关系良好,回收率为61%～117%,相对标准偏差为2.92%～18.98%。该法样品前处理简单、分析速度快、回收率和灵敏度高、检出限低,可以满足各国对牛奶中24种磺胺类药物的检测要求。     

固相萃取-胶束电动色谱法测定牛奶中的4种β-内酰胺类抗生素

建立了同时分离检测牛奶中的氨苄西林、阿莫西林、青霉素V和头孢氨苄4种β-内酰胺类抗生素的固相萃取-胶束电动色谱法。牛奶样品经沉淀蛋白后,采用HLB固相萃取柱净化浓缩;以含十二烷基硫酸钠(SDS)的磷酸盐为缓冲液,胶束电动色谱分离,210 nm波长下检测。分离电压为18 kV,于9 min内达到基线分离。各组分在0.5～20 mg/L范围内呈良好的线性关系,相关系数(r2)为0.9943～0.9976;检出限为0.16～0.20 mg/L;除了阿莫西林外,回收率均大于70%。该方法准确可靠,重复性好,灵敏度高,可以用于牛奶中β-内酰胺类抗生素的定量检测。     

液相色谱-串联质谱法测定牛奶中6种甲状腺拮抗剂残留

建立了牛奶中甲巯咪唑、硫脲嘧啶、甲基硫氧嘧啶、丙基硫氧嘧啶、苯基硫氧嘧啶和2-巯基苯并咪唑6种甲状腺拮抗剂残留的液相色谱-串联质谱分析方法.样品经乙腈沉淀蛋白后,上清液以衍生剂4-碘苄溴在pH=8.0下衍生2h,衍生液调节至pH=3.0,以乙酸乙酯提取.溶剂挥干后以20％甲醇复溶,Oasis HLB固相萃取小柱净化,4 mL 50％甲醇-乙腈溶液洗脱,Luna C18色谱柱分离,乙腈和5 mmol/L乙酸铵溶液(含0.2％甲酸)进行梯度洗脱,电喷雾正离子模式电离(ESI+),多反应监测(MRM)模式检测,内标法定量.结果表明:牛奶中6种目标物在优化条件下分离良好,响应值高,峰形尖锐对称,在5 ～ 100 μg/kg范围内呈良好的线性关系,相关系数r2均大于0.99;检出限为0.14～0.32 μg/kg,定量限为0.48～1.1 μg/kg;10,20和50 μg/kg添加水平的平均回收率为82.8％～ 113.6％,相对标准偏差2.4％～14.3％.     

高效液相色谱-串联质谱法检测牛奶中头孢洛宁残留

建立了牛奶中头孢洛宁残留检测的高效液相色谱-串联质谱方法。1 g牛奶经乙腈沉淀蛋白质后,上清液于37 ℃水浴下氮气吹干,用1 mL甲醇-0.1%甲酸水溶液（3：7,v/v）复溶,正己烷除脂净化后检测。流动相为乙腈和0.1%甲酸水溶液,梯度洗脱,经C₁₈色谱柱分离,采用多反应监测正离子模式对头孢洛宁进行定性定量分析。采用基质匹配法对牛奶中头孢洛宁的含量进行标准校正,在2~200 μg/L范围内,头孢洛宁质量浓度与其对应峰面积的线性关系良好,相关系数>0.999。牛奶中加标样品的检出限（按S/N≥3计）为0.5 μg/kg,定量限（S/N≥10计）为2 μg/kg。在定量限、1/2最高残留限量、最高残留限量、2倍最高残留限量添加水平下,牛奶中头孢洛宁的平均回收率为78.5%~86.2%,日内相对标准偏差为1.5%~6.2%,日间相对标准偏差为2.9%~5.6%。该方法可用于牛奶中头孢洛宁的残留检测。     

牛奶中2种青霉素残留的高效液相色谱柱前衍生法检测

利用金属铜离子和青霉素G、氨苄西林可在一定条件下形成稳定络合物,建立了一种高效液相色谱快速测定牛奶中2种青霉素残留的方法.样品经酸化乙腈沉淀蛋白,离心处理.色谱柱为Agilent TC C18(150 mm×4.6 mm I.d., 5 μm),甲醇-水为流动相,流速1.5 mL/min,检测波长320 nm,样品在5 min内完成分离检测.青霉素G和氨苄西林的质量浓度分别在0.05 ～1.0 mg/L、0.08 ～2.1 mg/L范围内呈良好的线性关系,相关系数分别为0.995 6、0.998 4.方法的检出限分别为1.5×10-5、2.4×10-5g/L,相对标准偏差分别为2.4%、1.8%(n=5).方法显示出较好的选择性和较高灵敏度,适于牛奶中青霉素G和氨苄西林残留的检测.     

固相萃取-高效液相色谱法同时测定牛奶中残留的9种磺胺类药物

建立了同时测定牛奶中残留的9种磺胺类药物的固相萃取-高效液相色谱分析方法。牛奶样品经磷酸盐缓冲液稀释后高速离心去除脂肪,过C18小柱,用水淋洗,甲醇洗脱,洗脱液经氮气吹干后用乙酸乙酯溶解,并过氨基固相萃取小柱净化,用正己烷及水淋洗,以甲醇-乙腈-水（含1%乙酸）(体积比为1∶1∶8)洗脱,洗脱液用于高效液相色谱分析。采用Inertsil ODS-3 C18柱分离,以水-乙酸和甲醇-乙腈为流动相进行梯度洗脱,二极管阵列检测器检测,外标法定量。9种磺胺类药物标准曲线的线性回归系数均在 0.9999 以上,线性范围为25～5000 μg/L,检出限为1.7～2.8 μg/L,定量限为5.7～9.2 μg/L。在10,20,40 μg/L 添加水平下的添加回收率为72.1%~88.3%,相对标准偏差为2.3%～5.0%。该方法具有快速、灵敏的特点,符合现行兽药残留分析的要求。     

Simultaneous determination of nine types of phthalate residues in commercial milk products using HPLC-ESI-MS-MS

A multi-residue method was developed for the confirmation and quantitation of nine types of phthalates in milk using high-performance liquid chromatography electrospray ionization tandem mass spectrometry. The samples were extracted with acetonitrile. The analytes were separated using a 0.1% formic acid-methanol system as the mobile phase, and a linear gradient elution program. Mass spectral acquisition was achieved by selectively monitoring the ions in electro-spray ionization mode. Qualitative analysis was based on the retention time and the mass spectrum results, and the quantity was carried out by comparison with the external standard. The mean recoveries for each analyte ranged from 65.2% to 98.3%, with relative standard deviations below 11.2%. The limits of detection were 5～25 μg/kg, and the limits of quantitation were 17～83 μg/kg, depending on the compounds. This method has the merits of convenient operation, high sensitivity, and good repeatability, making it an effective method for analysis of phthalates in milk. And the proposed analytical method has been applied to the analysis of phthalates presented in four commercial milk products. The main phthalate residues were DBP and DMP. And the amount of DBP was found to be more than 100 μg/kg in all this milk products.     

Determination of Sulfonamides in Bovine Milk by Ultra Performance Liquid Chromatography Combined with Quadrupole Mass Spectrometry

A novel method has been developed for the rapid separation and determination of 24 Sulfonamides (SAs) in bovine milk by using ultra-performance liquid chromatography tandem quadrupole mass spectrometry (UPLC-MS/MS) in ten minutes. Sulfonamides residues from bovine milk were treated with acetonitrile, followed by homogenizing, ultrasound treating, and centrifuging. The aforementioned procedure is repeated one additional time. A part of the extracts was taken to dryness and defatted twice. The analysis was performed on an Acquity UPLC^TM BEH C₁₈ column under the mobile phase which is composed of 0.2% acetic acid in water and acetonitrile. The analytes were detected by multiple reaction monitoring (MRM) in the positive ion scan mode. The calibration curves showed acceptable linearity in the concentration range from 0.2 to 100 ng mL^?1 with correlation coefficients (r²) above 0.992. The mean recoveries of 24 SAs in different standard-spiked levels were in the range of 60.59–116.66%; RSD% was 2.92%～18.64%. Results showed analytical category, separation speed, selectivity, sensitivity, and repeatability of sulfonamides in milk using UPLC-MS/MS that were significantly improved compared to other analytical methods.     

Rapid extraction and sample clean-up for the fluorescence densitometric determination of aflatoxin M1 in milk and mil powder

The diluted sample is passed through a SepPak C18 cartridge and the toxin is eluted with acetonitrile/water (3:7, v/v). The extract is cleaned up on a SepPak silica cartridge. The antidiagonal spot application technique is used for two-dimensional thin-layer chromatography. Spots are quantified by fluorescence densitometry. Recoveries of aflatoxin M1 added in the range 0.03-0.1 ng g^?1 of milk are 86–97%. The detection limit is about 0.005 ng g^?1 for milk and 0.05 ng g^?1 for milk powder.     

亲水作用色谱-四极杆/静电场轨道阱高分辨率质谱快速测定水样中氨基脲

建立了亲水作用色谱-四极杆/静电场轨道阱高分辨质谱快速检测水中氨基脲的方法。水样中加入0.1 mol/ L NaOH 溶液后,以乙腈为提取剂,加入过量 Na2 SO4,使乙腈与水分层,乙腈提取液再经无水 Na2 SO4脱水后,采用亲水作用色谱柱 Amide 色谱柱分离,以0.1%甲酸水溶液及0.1%甲酸乙腈溶液为流动相进行梯度洗脱,四极杆/静电场轨道阱高分辨率质谱电喷雾正离子、选择离子监测模式检测,同位素内标法进行定量分析。在最优实验条件下,氨基脲在0.2~20μg/ L 浓度范围内线性相关系数为0.997,方法的检出限为0.09μg/ L,定量限为0.30μg/ L。以淡水和海水为空白样品,在添加浓度为0.5,1.0和5.0μg/ kg 水平下,氨基脲的加标回收率为82.3%~92.0%,相对标准偏差小于7.6%。本方法适用于环境水样中氨基脲的快速分析。     

Isolation of tetracyclines in milk using a solid-phase extracting column and water eluent

An isolating method using a solid-phase extraction (SPE) ISOLUTE® C8 endcapped syringe-column for routine monitoring of residual tetracyclines (TCs) (oxytetracycline (OTC), tetracycline (TC), chlortetracycline (CTC), and doxycycline (DC)) in cow's milk is presented. In the simplest and most environmentally harmless method, milk samples could be applied directly to the SPE column, following which all TCs were eluted with water. No organic solvents were used at all. The purified sample was injected into a high-performance liquid chromatography (HPLC) with a photo-diode array detector (PDAD). For the HPLC determination/identification, a LiChrospher® 100 RP-8 endcapped column and a mobile phase of acetonitrile −7% (v v⁻¹) acetic acid solution (in water) (35:65, v v⁻¹) with a PDAD was used. The total time required for the analysis of one sample was <40 min. Average recoveries (spiked 0.1-1.0 μg ml⁻¹ each drug) and their standard deviations were >80 and <5%, respectively.     

Simultaneous determination of triclabendazole and its sulphoxide and sulphone metabolites in bovine milk by high-performance liquid chromatography

A simple method has been developed for the simultaneous determination of triclabendazole and its metabolites (sulphoxide and sulphone) in bovine milk by reversed-phase high-performance liquid chromatography (HPLC). A milk sample was homogenized with sodium sulfate anhydrous and acetonitrile, and centrifuged. The supernatant was isolated, rinsed with n-hexane saturated with acetonitrile, and evaporated. The residue was dissolved with 0.1 M potassium dihydrogenphosphate, and 0.1 M sodium hydrogencarbonate, and then cleaned up on a Bond Elut C18 cartridge. The three compounds were separated on a Capcell Pak C18 UG 120 (5 microm, 150x4.6 mm I.D.) column and determined by UV detection at 295 nm. The mobile phase was acetonitrile-0.05 M ammonium acetate (50:50), and the flow-rate was 0.8 ml/min at 40 degrees C. The mean recoveries (n=4) were 89.1-95.0% with a relative standard deviation of 1.1-2.6%. The detection limits were 0.004-0.006 microg/g in milk. The proposed method was used to monitor raw milk samples for the market, and applied to the analysis of milk samples from 10 cows which had been administered with triclabendazole to control the liver fluke. The confirmation of the triclabendazole and its metabolites in the above milk sample has been achieved by electrospray LC-MS for the first time.     

液相色谱-串联四极杆质谱法测定牛奶中128种农药残留

建立了牛奶中128种农药残留的液相色谱-串联质谱检测方法。10 mL牛奶用20 mL乙腈(加4 g硫酸镁和1 g氯化钠)振荡提取两次,上清液浓缩后经C18固相萃取柱(2000 mg填料)净化以除去提取液中的亲脂性化合物等干扰杂质,洗脱液浓缩至约0.5 mL后,于45 ℃下用氮气吹干,加1 mL乙腈-水(体积比为3:2)定容,超声溶解30 s,经0.2 μm微孔滤膜过滤,液相色谱-电喷雾串联质谱测定。2倍检出限和8倍检出限两个添加水平的5次平行实验结果表明: 128种农药在低添加水平(0.14 μg/L～0.62 mg/L)下回收率范围为60.4%～118.4%,相对标准偏差为2.1%～24.3%;高添加水平(0.56 μg/L～2.48 mg/L)下的回收率范围为64.4%～118.5%,相对标准偏差为1.3%～24.1%。各种农药在确定的添加范围内线性关系良好,相关系数高于0.99,方法的检出限(LOD)为0.07 μg/L～0.31 mg/L。该方法通用性强、选择性好、灵敏度高,快速简便。