超高压液相色谱-串联质谱测定茶叶中10种极性农药残留

建立了绿茶、乌龙茶、红茶和普洱茶中8种氨基甲酸酯和2种烟碱类农药等10种极性农药残留超高压液相色谱-串联质谱(UPLC-MS/MS)检测方法。茶叶样品经水润湿15 min后,乙腈提取,Carbon/NH2固相萃取净化,乙腈-甲苯(3:1V/V)淋洗。UPLC-MS/MS采用电喷雾电离(ESI),多反应监测模式(MRM)分析。方法在7.5,15,30μg/kg添加水平上回收率达到72.2%～92.5%,RSD≤9.2%。10种农药的基质效应因不同农药和不同种类茶叶基质存在较大差异,且均表现为基质抑制效应,因此校正工作液需采用相似茶叶空白基质配制。方法的定量限(LOQ)均达到7.5μg/kg.     

气相色谱-串联质谱法测定茶叶中83种农药残留

建立了气相色谱-串联质谱(GC-MS/MS)测定茶叶中83种农药残留的测定方法。茶叶样品经超纯水浸泡,用正己烷提取,过石墨化炭固相萃取小柱净化,待测农药在气相色谱-串联质谱(GC-MS/MS)上测定,用保留时间和特征离子对定性,外标法定量。在最佳的仪器条件下,待测农药在5～500μg/L线性关系良好,定量离子对的相关系数大于0.999,待测农药的检出限LOD(S/N=3)为2～20μg/kg,定量限LOQ(S/N>10)为5～50μg/kg。在空白茶叶样品中添加83种农药,添加水平分别为50、100、500μg/kg时,回收率范围在70.0%～110.0%,相对标准偏差(RSD)范围为3.2%～11.6%。对实际样品检测结果表明,大部分茶叶均有农药残留检出,主要为戊唑醇、溴虫腈、联苯菊酯、氯氟氰菊酯、氯氰菊酯、苯醚甲环唑、溴氰菊酯、唑虫酰胺,检出浓度集中在10～1 000μg/kg。该方法不但可以有效降低基线,减少杂峰的干扰,而且简单、灵敏、稳定,方法灵敏度满足国内外农药残留监测限量标准要求。     

固相萃取-气相色谱法测定茶叶中残留的92种农药

建立了茶叶中92种农药多残留的气相色谱分析方法。茶叶样品用乙腈一次性提取后,有机磷类农药经Envi-Carb固相小柱净化,用10 mL乙腈-甲苯(体积比为3∶1)洗脱剂淋洗,气相色谱-火焰光度检测器(GC-FPD)检测;有机氯类和拟除虫菊酯类农药经串联Envi-Carb和NH2固相小柱净化,用5 mL乙腈-甲苯(体积比为3∶1)洗脱剂淋洗,GC-电子捕获检测器(ECD)检测。采用外标法定量。添加回收试验的结果表明:92种农药的平均回收率为80.3%～117.1%,相对标准偏差为1.5%～9.8%。方法的检出限为0.0025～0.10 mg/kg。该方法的灵敏度、准确度和精密度均符合农药残留测定的技术要求。     

固相萃取净化-气相色谱/串联质谱法测定茶叶中54种农药残留量

建立了固相萃取净化-气相色谱/串联质谱(SPE-GC-MS/MS)分析茶叶中54种农药残留的方法。样品用乙睛提取,提取液经石墨化炭黑/氨基固相萃取柱净化后,采用气相色谱-串联质谱方法在分时段选择反应监测模式下进行测定,外标法定量。当54种农药加标水平为10、50、100μg/kg时,回收率为60%～150%,方法的相对标准偏差小于16%;定量限(LOQ)均小于10μg/kg;在20～320μg/L范围内线性关系良好。方法已用于同时检测茶叶中农药多残留。     

固相萃取-气相色谱检测茶叶中啶虫脒残留量

建立了茶叶中啶虫脒残留量的气相色谱分析方法.样品用乙腈超声提取,经Envi-Forisil固相小柱净化,以V(石油醚):V(丙酮)=1:1洗脱,GC-ECD检测,外标法定量.在0.01～0.10 mg/kg的添加水平,平均回收率在90.9～94.2%之间,相对标准偏差在1.6%～3.4%,该方法的检出限为0.01 mg/kg.该方法的灵敏度、准确度和精密度均符合农药残留测定的技术要求.     

微波辅助萃取法测定烟草中有机氯类农药残留量

建立了一种微波辅助萃取-固相萃取净化测定烟草中17种有机氯类农药残留量的新方法. 样品用V(正己烷):V(乙酸乙酯)＝1:1提取, 提取液经Florisil固相萃取柱净化后, 采用气相色谱-电子捕获检测器(GC-μECD)进行检测. 17种有机氯农药的0.01、 0.05 mg/kg和0.5 mg/kg加标回收率均在82%以上, RSD在0.11%～8.2%之间, 能满足当前烟草中有机氯农药残留的检测要求.     

气相色谱-负化学源质谱法测定豆类中14种农药残留

建立了以凝胶渗透色谱(GPC)和固相萃取法净化、气相色谱-负化学离子源-质谱(GC-NCI-MS)联用法测定豆类(毛豆、荷兰豆、豌豆、蚕豆等)中14种农药残留的分析方法。样品经提取液经GPC净化除去大部分的油脂和色素,再经乙二胺-N-丙基甲硅烷(PSA)小柱净化,目标农药采用GC-NCI-MS检测,外标法定量。添加50μg/kg浓度水平时,农药回收率在42.2%~124.5%之间,相对标准偏差在1.10%~8.72%之间;农药的检测限在0.5~10.0μg/kg(3倍信噪比)之间。方法净化效果好,灵敏度高,可满足进出口豆类农药多残留检测实际工作的需要。     

气相色谱-质谱法测定花生及制品中17种菊酯类农药残留

建立了花生及制品中17种菊酯类农药残留量的分析方法。样品与C18/弗罗里硅土(1∶2,w/w)填料混合,基质固相分散(MSPD)提取,以乙酸乙酯/环己烷(1∶1,V/V)洗脱待测物。MSPD提取液经凝胶渗透色谱净化后采用气相色谱负化学源质谱检测。结果表明,氯菊酯在10～500μg/L,其余16种农药在5～500μg/L范围内具有良好的线性关系,相关系数为0.9992～0.9999。17种农药在10～500μg/kg范围内的加标回收率为72.6%～102.9%,相对标准偏差为2.9%～7.8%,检出限为0.33～6.6μg/kg,定量限为1.1～21.9μg/kg。本方法操作简单、净化效果好、灵敏度高,可应用于花生及制品中17种菊酯类农药的实际检测分析。     

超高效液相色谱法快速测定发酵茶叶中的黄曲霉毒素

建立了用超高效液相色谱/紫外检测器测定发酵茶叶中黄曲霉毒素B1、B2、G1和G2的方法.用CH2Q2提取黄曲霉毒素,提取液经浓缩后,用LC-CN固相萃取小柱净化,超高效液相色谱测定.在浓度范围20～200μg/L(B1、G1),15～120μg/L(B2、G2)内具有良好的线性相关关系.黄曲霉毒素的回收率为81.4%～92.3%,相对标准偏差RSD 1.6%～4.2%.检出限为0.32μg/kg(B1、G1),0.18μg/kg(B2、G2)(S/N=3).     

浊点萃取-异辛烷反萃取-气相色谱测定茶叶中拟除虫菊酯农药残留

建立了浊点萃取-异辛烷反萃取-气相色谱(ECD)检测茶叶中联苯菊酯(Bifenthrin)、甲氰菊酯(Fenpropathrin)、功夫菊酯(Cyhalothrin)、氯菊酯(Permethrin)、氰戊菊酯(Fenvalerate)、溴氰菊酯(Deltamethrin)6种拟除虫菊酯农药残留的方法.对含1.2%(m/V)聚乙二醇6000(PEG6000)表面活性剂和40%(m/V)(NH4)2SO4的6种拟除虫菊酯溶液进行加热萃取,所获得的富集相用异辛烷超声反萃取,并经离心对上层异辛烷溶液进行进一步净化处理,即可获得富集倍数达75倍的6种农药.本方法的检出限(LOD)为:联苯菊酯、甲氰菊酯和功夫菊酯0.4 μg/kg;氰戊菊酯2.1 μg/kg;氯菊酯和溴氰菊酯3.0 μg/kg;用本方法测定了新鲜茶叶中6种拟除虫菊酯农药,含量分别为4.17, 4.15, 4.09, 4.01, 3.93和3.51 μg/kg.在上述茶叶样品中添加20 μg/kg 的6种农药后测定,添加回收率为72.3%～85.6%; 相对标准偏差为2.2%～5.6%.     

液相色谱-串联质谱检测贝类组织中5种脂溶性贝毒素

建立了液相色谱-串联质谱分析贝类组织中米氏裸甲藻(GYM)贝毒素、螺环内酯毒素(SPX1)、大田软骨酸(OA)贝毒素、蛤毒素(PTX2)、原多甲藻酸(AZA1)贝毒素的方法.用甲醇-水(4: 1, V/V)溶液对贝类组织中GYM, SPX1, OA, PTX2和AZA1进行提取,MAX阴离子交换柱净化后,采用液相色谱分离,除OA以负离子选择反应监测外,GYM, SPX1, PTX2和AZA1以电喷雾离子源正离子选择反应监测模式进行质谱分析.5种脂溶性贝毒素GYM, SPX1, OA, PTX2和AZA1在各自相应浓度范围内线性良好,相关系数＞0.99.扇贝闭壳肌空白样品添加5种贝毒素的提取率均为78.6%～94.4%(n=6); 精密度(RSD)为6.8%～14.9%.贝类组织中5种贝毒素GYM, SPX1, OA, PTX2和AZA1的检出限分别为0.10, 0.21, 2.00, 0.32和0.04 μg/kg.     

液相色谱-串联质谱法检测贝类产品中腹泻性贝类毒素

建立了贝类组织中2种腹泻性贝毒(Diamletic shellfish Poisobing,DSP)聚醚类毒素-大田软海绵酸(Okadaic acid,OA)和鳍藻毒素(Dinophysistoxin-1,DTX-1)的高效液相色谱-串联质谱分析方法.贝类样品经80%甲醇溶液提取,经正己烷脱脂和HLB固相萃取柱净化,采...     

高效液相色谱-串联质谱法检测花生中的黄曲霉毒素B_1

应用高效液相色谱-电喷雾串联四极杆质谱联用系统(HPLC-MS/MS),在多反应离子检测方式(MRM)下,对花生中的黄曲霉毒素B1进行检测.对花生中黄曲霉毒素B1的提取、净化、液相分离及串联质谱等相关检测参数进行了优化研究.用V(甲醇):V(水)=6:4提取,OASIS HLB SPE小柱净化,定容过滤.采用V(甲醇):V(水)(含体积分数0.1%甲酸)=7:3为流动相,前级离子313.0,二级离子241.1、269.1,ESI正离子方式检测,在3.3 min出峰.结果表明,在ESI正离子模式下,黄曲霉毒素B1在其线性定量范围0.1～50μg/kg内,相关系数达到0.9999,检出限为0.03μg/kg,最低定量限为0.1μg/kg.低、中、高浓度添加回收率范围为93%～105%.     

“抑制-萃取”法从含铁酸溶液中选择性提钒

酸法浸出石煤提钒因具有环保、金属收率高的特点而备受关注,但同时进入母液的铁(高含量的Fe³⁺)严重影响了钒的富集和产品生产。 对此,本文提出一种基于“抑制-萃取”效应的钒/铁分离混合萃取体系(P507(2-乙基己基磷酸-单2-乙基己基酯)+ N235(三辛/癸烷基叔胺)+磺化煤油),并详细研究了各因素对钒铁分离和钒富集的影响规律。 结果表明,P507是钒铁萃取的主体,N235不具萃Fe³⁺能力,是产生抑制铁萃取的关键因素,其浓度越高铁萃取率越低;对于酸度较高(pH≤0.4)的原料液钒/铁的分离效果仍较好,这表明了该“抑制-萃取”混合萃取体系对高酸度浸出液钒/铁分离的适用性。 采用氨水从负载有机相中反萃取钒铁,当氨水浓度为6 mol/L时钒的反萃率99%以上,25 ℃,V(有机相)∶V(水相)=2∶1时的反萃液中钒质量浓度14.73 g/L,铁质量浓度小于0.022 g/L,m(V)/m(Fe)=669.5。 该“抑制-萃取”法分离钒/铁操作简单、经济高效,极具工业化前景。     

液相色谱-电喷雾电离/离子阱质谱法分析金线莲中3-吡啶甲醇

应用现代提取技术超声-微波协同萃取金线莲中的3-吡啶甲醇,采用固相萃取技术对样品进行前处理,高效液相色谱法-电喷雾电离/离子阱质谱法(HPLC-ESI/MS)对提取物中3-吡啶甲醇进行测定和鉴别.色谱条件:Agilent TC-C₁₈色谱柱(5 μm,4.6×250 mm),流动相:甲醇-0.02 mol/L乙酸铵(5∶95,V/V),流速:1 mL/min,检测波长:260 nm.结果表明峰面积与3-吡啶甲醇在浓度1~10 μg/mL范围内呈良好线性关系.回收率在92.0%~96.2%之间,相对标准偏差为2.36%.该法简便、准确、快速.     

同位素稀释-超高效液相色谱-线性离子阱串联质谱分析谷物及其制品中呕吐毒素及其衍生物和代谢物

建立了谷物及其制品中脱氧雪腐镰刀菌烯醇、3-乙酰脱氧雪腐镰刀菌烯醇、15-乙酰脱氧雪腐镰刀菌烯醇、去环氧脱氧雪腐镰刀菌烯醇的同位素稀释-超高效液相色谱-线性离子阱串联质谱( UHPLC-QTRAP-MS/MS)定性确证和定量测定方法。样品经乙腈-水(84：16, V/V)混合溶液提取,乙腈饱和的正己烷除脂,HLB固相萃取柱净化,Waters Atlantis? T3色谱柱分离,以乙腈-0.02%氨水溶液为流动相进行梯度洗脱,在负离子模式下,采用多反应监测( MRM)-信息依赖性采集( IDA)-增强子离子扫描( EPI)模式检测,在线EPI谱库定性分析,同位素内标定量,在1~300μg/L 浓度范围内,4种目标物的线性相关系数均大于0.999,检出限为0.1μg/kg,定量限为0.3μg/kg,添加5,50和200μg/kg的3个浓度水平,4种目标物的平均回收率均在81.3%~101.7%之间,相对标准偏差均小于5%,将该技术应用于FAPAS阳性玉米质控样品和5种代表性的样品进行测试,结果表明,本方法简单、准确、快速,适用于谷物及其制品中呕吐毒素及其衍生物和代谢物的快速确证和定量测定。     

Extraction and detection of arsenicals in seaweed via accelerated solvent extraction with ion chromatographic separation and ICP-MS detection

An accelerated solvent extraction (ASE) device was evaluated as a semi-automated means of extracting arsenicals from ribbon kelp. The effect of the experimentally controllable ASE parameters (pressure, temperature, static time, and solvent composition) on the extraction efficiencies of arsenicals from seaweed was investigated. The extraction efficiencies for ribbon kelp (approximately 72.6%) using the ASE were fairly independent (< 7%) of pressure, static time and particle size after 3 ASE extraction cycles. The optimum extraction conditions for the ribbon kelp were obtained by using a 3 mL ASE cell, 30/70 (w/w) MeOH/H2O, 500 psi (1 psi = 7 KPa), ambient temperature, 1 min heat step, 1 min static step, 90% vol. flush, and a 120 s purge. Using these conditions, two other seaweed products produced extraction efficiencies of 25.6% and 50.5%. The inorganic species present in the extract represented 62.5% and 27.8% of the extracted arsenic. The speciation results indicated that both seaweed products contained 4 different arsenosugars, DMA (dimethylarsinic acid), and As(V). One seaweed product also contained As(III). Both of these seaweed products contained an arsenosugar whose molecular weight was determined to be 408 and its structure was tentatively identified using ion chromatography-electrospray ionization-mass spectrometry/mass spectrometry (IC-ESI-MS/MS).     

Application of factorial designs and Doehlert matrix in optimization of experimental variables associated with the preconcentration and determination of vanadium and copper in seawater by inductively coupled plasma optical emission spectrometry

In the present paper a procedure for preconcentration and determination of vanadium and copper in seawater using inductively coupled plasma optical emission spectrometry (ICP OES) is proposed, which is based on solid-phase extraction of vanadium (IV), vanadium (V) and copper (II) ions as 1-(2-pyridylazo)-2-naphthol (PAN) complexes by active carbon. The optimization process was carried out using two-level full factorials and Doehlert matrix designs. Four variables (PAN mass, pH, active carbon mass and shaking time) were regarded as factors in the optimization. Results of the two-level full factorial design 2⁴ with 16 runs for vanadium extraction, based on the variance analysis (ANOVA), demonstrated that the factors pH and active carbon mass, besides the interaction (pH×active carbon mass), are statistically significant. For copper, the ANOVA revealed that the factors PAN mass, pH and active carbon mass and the interactions (PAN mass×pH) and (pH×active carbon mass) are statistically significant. Doehlert designs were applied in order to determine the optimum conditions for extraction. The procedure proposed allowed the determination of vanadium and copper with detection limits (3σ/S) of 73 and 94 ng l⁻¹, respectively. The precision, calculated as relative standard deviation (R.S.D.), was 1.22 and 1.37% for 12.50 μg l⁻¹ of vanadium and copper, respectively. The preconcentration factor was 80. The recovery achieved for determination of vanadium and copper in the presence of several cations demonstrated that this procedure improved the selectivity required for seawater analysis. The procedure was applied to the determination of vanadium and copper in seawater samples collected in Salvador City, Brazil. Results showed good agreement with other data reported in the literature.     

Potential‐driven peptide extractions across supported liquid membranes: Investigation of principal operational parameters

Fundamental experiments on electromembrane extraction were performed to increase the basic knowledge about the current and the mass transfer of target peptides and background electrolyte ions. Three peptides (angiotensin 2, bradykinin, and enkephalin) were extracted from 500 μL aqueous donor solution (1 mM HCl, positive electrode), through a 200 μm supported liquid membrane (SLM) of 1‐octanol/di‐isobutylketon/di‐(2‐ethylhexyl) phosphate (55:35:10 w/w/w) sustained in the pores of a porous hollow fiber, and into 25 μL aqueous acceptor solution (50 mM HCl, negative electrode) present inside the lumen of the fiber by the application of an electrical potential (50 V) and agitation (1050 rpm). Recoveries were typically in the range of 55–65% after 5 min of extraction and were principally determined by the chemical composition of the SLM and by the applied voltage. The electrical current in the system was measured during the extraction and was close to 350 μA. The current arose to some extent from mass transfer of the target peptides, but the major contribution was due to a background current from di‐(2‐ethylhexyl) phosphate in the SLM and from mass transfer of background electrolytes. Operation at relatively low background current was important to maintain a stable system.     

蔬菜和食用菌中氨基甲酸酯类农药残留检测技术

建立了丙酮和乙腈(体积比85:15)提取,凝胶渗透色谱(GPC)法和PSA(N-丙基乙二胺)固相萃取柱2种方法净化,超高效液相色谱-串联质谱（UPLC-MS/MS）同时检测菠菜、黄瓜、大葱、蘑菇、香菇、木耳、牛肝菌和胡萝卜中19种氨基甲酸酯类农药,同位素稀释法定量。实验结果表明,GPC法净化,回收率为70.1%～95.7%;PSA固相萃取柱净化,回收率为70.2%～94.9%。方法的检出限均为1×10-5 g/kg。各种NMCs在确定的添加范围内线性关系良好,线性相关系数r均＞0.99,所建立的检测方法实用、准确、灵敏度高。