基于基质固相分散萃取的茶叶中拟除虫菊酯多农残气相色谱测定

建立了一种快速又简便的气相色谱电子捕获检测(GC-μECD)测定茶叶中8种拟除虫菊酯农药残留的方法,采用了新的样品前处理方法—基质固相分散(MSPD)对残留农药进行提取和净化。8种农药的回收率在80.4%～109.2%,相对标准偏差小于10%。实验表明这种方法适用于茶叶样品的拟除虫菊酯农药残留分析。     

QuEChERS_GPC_GC_MS快速测定蔬菜中24种农药残留

采用QuEChERS前处理方法和在线凝胶渗透色谱-气相色谱质谱联用仪(gel permeation chromatography-gas chromatography/mass spectrometry,GPC-GC/MS)快速测定蔬菜中24种多农药残留。样品经乙腈提取,净化采用分散固相萃取的方式,加标浓度为0.1 mg/kg,油麦菜样品中的24种农药回收率大部分在70%～120%,24种农药的检出限范围在0.000 2～0.009 mg/kg,线性范围0.025～0.30 mg/L,相对标准偏差在1.41%～10.05%,满足农药多残留的分析要求。实验表明,QuEChERS方法提取和净化使样品前处理更为简单、方便、快速,GPC-GC/MS系统中的GPC柱弥补了QuEChERS方法去除干扰物不彻底的问题,能更准确地检测出蔬菜中多农药残留,检测灵敏度高,重现性好。     

气相色谱法检测茶园土壤中有机氯农药残留量

采用气相色谱法检测茶园土壤中8种有机氯农药组分的残留量，平均回收率在76．5％～105．4％之间，相对标准偏差在3．82％～10．97％之间，检出限为0．0001～0．001mg／kg。结果表明：本方法方便、快速、准确性高，适用于土壤样品的农残检测。     

多壁碳纳米管分散固相萃取气相色谱-质谱法测定红甜菜中10种农药残留

以多壁碳纳米管分散固相萃取作为前处理手段,气相色谱-质谱法进行检测,建立了红甜菜中10种农药残留的测定方法。样品经乙腈提取,多壁碳纳米管、PSA、MgSO4分散固相萃取去除杂质,选择离子监测模式,外标法定量,对甜菜中10种农药残留进行了联合测定。结果表明:10种农药的浓度线性范围在10(或者30)μg/L～0.5 mg/L之间,相关系数(R2)均大于0.99。10种农药的平均回收率在73.8%～99.2%之间,相对标准偏差为2.3%～8.25%,最低检出限为1～9μg/kg。此方法简便、快速且具有较高的灵敏度,符合农药多残留分析的要求。     

在线凝胶色谱-气相色谱质谱测定菠菜中55种农药残留

运用在线凝胶色谱-气相色谱质谱联用(GPC-GC/MS)技术,建立一种快速、准确测定菠菜样品中55种农药残留的方法。样品用乙腈提取,经盐析、PSA净化后,使用GPC-GC/MS进行检测。结果表明：各组分分离良好,在0.025、0.05及0.10 mg/kg 3个添加水平,55种农药的回收率在81.3%～106.2%,相对标准偏差均低于10.3%;在0.01～0.5 μg/mL浓度范围内,线性关系良好,相关系数均大于0.995 3;55种农药的检出限为0.005～0.5 μg/kg。该方法准确、灵敏、快速,可满足对菠菜中55种农药残留的检测需要。     

超快速高效液相色谱法测定普通白菜中16种氨基甲酸酯类农药残留

研究应用超快速高效液相色谱仪柱后衍生荧光检测器同时测定普通白菜中16种氨基甲酸酯类农药残留。对流动相组成、波长选择、梯度洗脱等条件进行比较研究,建立了样品经乙腈提取,SPE-NH2固相萃取柱净化,液相色谱柱后衍生分离,荧光检测(λex＝339 nm, λem＝445 nm)测定,外标法定量的检测方法。研究表明：基于液相色谱荧光检测条件,16种农药残留在0.025～1.0 mg/L浓度范围内线性关系良好;检出限0.002～0.010 mg/L;平均加标回收率73.0%～103.0%,相对标准偏差(RSD)1.5%～8.8%。该研究确定的方法具有检测范围广、快速、灵敏、准确、重现性好、易推广等特点。     

刍议无公害茶叶栽培与加工综合控制技术

茶叶是饮料食品,我国及茶叶进口国对农药残留量和重金属含量有严格的标准规定,检测范围也随之扩大,过去欧盟检验茶叶中农药的种类只有6种,现在已扩大到10多种,在扩大农药检测范围的同时,又将多种农药的MRL标准降低了10～100倍,如氰戊菊脂残留量原标准为10mg/kg,现降至0.1mg/kg。 我国茶叶中农药残留量是世界上出口国中超标率较高的国家之一,据中国茶叶研究所2000年对2000个出口茶叶样品的检测分析结果显示,氰戊菊脂在乌龙茶和花茶中超标率为71.5～84.2％,甲氰菊脂为32.5～66.6％。以甲氰菊脂为例,乌龙茶100％超标,花茶44.2％超标,使得我国茶叶出口处于非常不利的境地。因此茶叶无公害栽培、加工及病虫害综合控制,切实解决茶叶污染问题,是保障人民身体健康,拓展国内外茶叶市场,提高茶农经济效益的有效措施。     

大豆、花生及粮油中56种农药残留量的检测方法

为研究高油脂植物源性样品粮谷和粮油中的农药残留量,本研究建立了气相色谱/串联三重四级杆质谱法(GC/MS/MS)能够快速、简单、同时测定大豆、花生及其粮油中56种农药残留,并对MS/MS检测参数及样品前处理方式进行了优化。样品经乙腈提取后,冷冻、离心,串联C18/PSA固相萃取柱净化,采用气相色谱/串联三重四级杆质谱仪检测,56种农药在线性范围内均呈现良好的线性关系,线性系数大于0.99。本检测方法的检出限(LOD)为0.001~0.005 mg·kg~(-1),方法验证试验结果表明,该类化合物的平均回收率为62%~116%,相对标准偏差(RSD)为0.82%~14.5%。本方法重现性好,精密度高,操作简单,适用于大豆、花生及其粮油类高油脂植物源性食品中多种农药残留的检测。     

测定茶叶中22种有机磷农药残留的气相色谱法

建立了气相色谱法同时测定茶叶中22种有机磷农药残留的方法。样品用正己烷-乙酸乙酯(1:1,v/v)混合溶剂提取,经固相萃取小柱净化,采用CP-Sil 24 CB色谱柱分离,18MIN内在气相色谱上实现22种有机磷农药残留分析。采用外标法定量分析,在0.02～0.2μg/ml范围内线性关系良好,检出限为0.005～0.02 mg/kg,回收率为78%～120%,相对标准偏差为2.3%～7.7%。该方法简便、快速、准确、重现性好、灵敏度高,适用于实际检测。     

花生及花生油中危害物污染调查

为了解花生及花生油中危害物污染情况,本研究共收集25份花生样品和21份花生油样品开展危害物污染调查,其中花生进行农残污染调查,花生油进行农残、苯并芘和塑化剂污染调查。结果表明,花生和花生油样品均未检测到农药超标,其中13份花生样品和8份花生油样品检测到农药残留,检出率分别为52.00%和38.10%;9份样品检出1种农药残留,12份样品检出2种及以上农药残留;杀虫剂毒死蜱的检出率较高,为34.78%;花生油中苯并芘的检出范围为1～5μg/kg,均未超出国家标准;5份花生油样品检出塑化剂,检出率为23.81%,1份花生油样品塑化剂超标,超标率为4.76%。本研究为花生及花生油中危害物的防控提供了数据支撑。     

基质固相分散萃取-高效液相色谱串联质谱法（HPLC-MS-MS）同时测定茶叶中11种农药的残留量

建立了茶叶中3类11种农药的分散固相萃取–高效液相色谱串联质谱（HPLC-MS-MS）的检测方法。茶叶样品以乙腈–乙酸（体积比99:1）提取,以PSA为净化剂基质固相分散萃取,然后通过C₁₈色谱柱,以甲醇/水（含甲酸铵）溶液进行梯度洗脱,采用电离喷雾电离方式（ESI+）,通过多反应监测（MRM）定量。结果表明：11种农药的分析时间约为20 min,在0~500 ng·mL^-1范围内线性相关,相关系数大于0.9995,方法检测限为0.1~1.7 μg·kg^-1。测定了茶叶样品中11种农药的残留量,加标回收率为62.4%~114.8%（添加水平分别为10~400 μg·kg^-1）,相对标准偏差（RSD）为3.28%~19.34%。选取了5个不同类型的茶叶样品,检测其中11种农药的残留量,检出结果差异较大。其中绿茶中11种农药的检出量为1.7~339.4 μg·kg^-1,加标回收率为86.1%~104.1%,相对标准偏差（RSD）均小于20%（n=6）。本方法准确、灵敏、简单、快速、安全,能满足茶叶样品中多种农药残留分析的要求。     

微波消解HG-AFS法测定小麦中硒含量的研究

为了探讨小麦中硒含量的快速测定方法,本文考察了酸消解体系、微波功率、消解时间、酸用量等因素对利用微波消解HG—AFS法测定小麦中硒含量结果的影响,优选出了仪器的最佳工作条件,并以最佳样品消解条件和仪器工作条件测定5种小麦样品和国家小麦标准物质(GBW08503)中的硒含量。结果表明,小麦标准物质中硒的测定值与标准值相吻合,5种小麦样品中硒的相对标准偏差在5.44%～8.21%之间,本法的检出限为0.052ng·ml-1,浓度在0～200ng·ml-1范围内呈良好的线性关系,且具有操作简便、快速、灵敏度高、污染小等特点。     

Characterization of HMW glutenin subunits in common wheat and related species by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS)

The sample preparation method of high molecular weight glutenin subunits (HMW-GS) for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis, without a separation step, by high-performance liquid chromatography (HPLC) was established in this study. Three major factors influencing mass spectra—the ratio of components of the solvent, the resolving time, and the sample volume—were optimized using HMW-GS mixtures extracted from Chinese cultivar Jing 411. The results showed that the optimized method for sample preparation was to resolve HMW-GS from 20 mg in an hour with 50 μl solvent of 0.4% TFA, 30.0% ACN and 69.6% H₂O. The stable mass spectra and accurate molecular weights of 16 major HMW glutenin subunits from common wheat and related species were obtained using the optimized MALDI-TOF-MS method. Seven subunits, where each was from 2–5 cultivars, showed very similar molecular weights. The determined molecular weights of 11 subunits were close to those calculated from their coding sequences. In addition, no positive reaction between HMW-GS and GelCode^® Glycoprotein Staining Reagent was observed. These results suggested that HMW-GS lack extensive post-translational modifications (PTMs), but low levels of glycosylation or phosphorylation present in some subunits cannot be ruled out. Because of its ability to obtain a rapid, complete and precise profile of HMW glutenin subunits without purifying procedures, MALDI-TOF-MS is expected to be a powerful technique for structural and functional studies of HMW glutenin subunits as well as other cereal proteins.     

利用连续流动分析仪快速测定碱熔法土壤全磷

根据 AA3 型连续流动分析仪（简称 CFA）测定磷的原理,研究了用 CFA 快速测定碱熔法待测液中土壤全磷 的方法。结果表明：通过优化 CFA 进样冲洗液及显色液的酸度,土壤全磷的标准曲线,在 0~8 mg/L 范围内呈线性相 关,相关系数 R2 达 1.000 0;全磷含量不同的 3 个土壤样品待测液 10 次重复测定结果变异系数≤2.0%;样品加标回收 率为 99.08%~102.42%;土壤成分分析标准物质 GBW07408 土壤全磷 CFA 法测定结果与其参考值一致,CFA 法与碱熔 钼锑抗手工比色法测定结果无显著差异。且由于 CFA 法去除了手工法中显色前样品酸度的调节步骤,因此 CFA 法具有 快速、准确测定碱熔法待测液中土壤全磷的效果。     

Determination of thiabendazole residues in potatoes using high pressure liquid chromatography

Summary This paper describes a method for the extraction, purification and quantification by high pressure liquid chromatography using fluorimetric detection, of thiabendazole residues from potatoes. Bonded silica sorbent extraction columns (diol phase) are used for sample clean up, resulting in a rapid and accurate analysis. The average recovery was 93.8%±2.1%. Levels of about 0.0004μg of TBZ, equivalent to 0.033 mg kg⁻¹ in potatoes (on fresh weight basis), were readily detected from deliberately contaminted potatoes.     

食品中人参总皂苷的测定方法研究

目的建立一种快速准确的分光光度法测定食品中人参皂苷的含量。方法采用不同前处理方式对不同类型的样品进行预处理,应用分光光度法测定人参皂苷的含量。结果人参皂苷在0μg~100μg范围内具有良好的线性,相关系数为0.9981,检出限为0.0025g/100g,相对标准偏差(RSD)为2.36%~8.56%,加标回收率在80.8%~103.3%之间。结论:该方法简便快速、准确灵敏,适用于测定食品中人参皂苷的含量。     

HPLC-ELSD法测定甘蔗叶片蔗糖含量

利用水提法提取甘蔗叶片中的糖类,采用Xbridge NH2色谱柱,流动相为乙腈 ∶ 水（70 ∶ 30,V/V）加0.1％ NH4OH,流速1.0 mL/min,柱温25.0 ℃,建立了一种高效、快速的测定甘蔗叶片中蔗糖含量的高效液相色谱——蒸发光散射检测法（High Performance Liquid Chromatography with Evaporative Light Scattering Detector, HPLC-ELSD）。在该方法中,ELSD检测器漂移管温度为 85.0 ℃, 氮气流速为2.0 L/min,增益为2。在以上条件下,蔗糖标准品能与糖类标准品中的其它糖类明显分开,甘蔗叶片中蔗糖也能与其它糖类明显分开,分离效果均良好。蔗糖浓度为0.2~0.9 mg/mL时,呈良好的线性关系（R2=0.994 4）。本方法精密度达到2.0％,表明仪器的精密度良好;蔗糖回收率为99.7％,说明本方法的回收率良好;通过间隔一定时间多次试验,测定蔗糖在提取液中的稳定性,结果表明多次试验误差为0.9％,表明此样品抽提法获得的样品较为稳定。     

A novel method for ash analysis in wheat milling fractions by using laser-induced breakdown spectroscopy

Ash content is an important quality control parameter in milling industry. Measurement of ash content is routinely performed using standard ash analysis method in which the sample is burned at 500–600 °C for 5–6 h. However, this method is not convenient for industrial applications, and thus, rapid and reliable methods are needed to be developed. The aim of this study was to develop a new method for ash analysis to be used in wheat milling fractions by using laser induced breakdown spectroscopy (LIBS). LIBS is an optic based multi-elemental, spectroscopic method which can analyze high number of samples in a considerably short time. In the study, wheat flour, whole wheat meal and semolina samples with different ash contents were analyzed using LIBS, and the spectra were evaluated with partial least squares (PLS) method. The results were correlated with the ones taken from standard ash analysis method. Calibration graph showed good linearity with the ash content between 0.48 and 2.44%, and 0.997 coefficient of determination (R²). Limit of detection for ash analysis was calculated as 0.11%. The results indicated that LIBS is a promising and reliable method with high sensitivity for routine ash analysis in milling industry.     

高效液相色谱法测定发酵液中的吲哚乙酸含量

建立了发酵液中吲哚乙酸含量测定的高效液相色谱法。样品经乙酸乙酯萃取、分层后，取乙酸乙酯层抽真空浓缩至干，残渣用甲醇溶解定容。色谱条件为：C18柱，以乙腈∶2 %醋酸水溶液=1∶4为流动相，采用紫外检测器在280 nm处对样品中的吲哚乙酸进行测定高效液相色谱法测定。测定结果表明，吲哚乙酸在0-5 mg/L时其峰面积与进样质量的线性相关系数达到0.999 8，峰面积测定的相对标准偏差(RSD)3.5 %(n=6)。试样加标回收率为97.6-106 %。测定结果显示，该方法快速、灵敏、可靠，具有简便、重现性好的特点。     

Ultra-fast separation of wheat glutenin subunits by reversed-phase HPLC using a superficially porous silica-based column

A relatively new, unique column packing material for reversed-phase high-performance liquid chromatography (RP-HPLC) was evaluated for rapid separation of wheat glutenin protein subunits. The product named “Poroshell” by the manufacturer consists of a solid core and a porous coat instead of solid silica spheres used in conventional RP-HPLC column packing. This architecture favours rapid mass transfer, facilitating faster reversed-phase separations of biomolecules compared to conventional silica columns. The main objective of this study was to evaluate the quality of separations of glutenin subunits (GS), as well as to optimize conditions to produce the fastest possible run times without sacrificing resolution using a Poroshell 300SB-C₈ 2.1×75 mm column. The stability of GS separations over time was also assessed. Two different bread wheat genotypes were used for optimization of separation conditions and six more common and durum wheat genotypes possessing different subunit combinations were used for further evaluation. Glutenin protein was extracted with 0.08 M Tris–HCl buffer (pH 7.5) containing 50% 1-propanol under reducing conditions after pre-extraction of soluble proteins with 50% 1-propanol. Optimization of GS resolution and sample throughput by RP-HPLC was assessed in response to variation in eluent flow rate, acetonitrile (ACN) gradient, and column temperature. The best resolution of both HMW- and LMW-GS was obtained in 13 min using a 23–44% ACN gradient with a flow rate of 0.7 mL/min at 65 °C. Subunit elution times and integrated areas were highly repeatable even after several hundred injections. Highly satisfactory separation of HMW-GS and quantification of ratio of HMW- to LMW-GS were achieved in less than 4 min per sample using a modified HPLC gradient. Ratio of HMW- to LMW-GS was unaffected by the speed of the separations. As well, the elution order of HMW- and LMW-GS was unaffected by the rapid analysis, compared to conventional RP-HPLC separations, so no new learning was required for interpreting chromatograms and classification of subunits. The rapid RP-HPLC method using the Poroshell column appears to be very well suited for routine quantification of HMW-GS and LMW-GS especially for purposes of wheat quality screening and wheat cultivar development activities where large numbers of samples are typically encountered.