Time-resolved fluoroimmunoassay for 19-nortestosterone residues in aquaculture tissues.

A competitive time-resolved fluoroimmunoassay (TR-FIA) was developed for the determination of 19-nortestosterone (17beta-NT) residues in aquaculture tissues. The limit of detection (LOD) was determined to be 0.08 ng g-1 and the limit of quantification (LOQ) was less than 0.8 ng g-1. The results obtained by the TR-FIA and ELISA showed a good correlation. The established TR-FIA was validated for the determination of incurred aquaculture tissues and confirmed by liquid chromatography tandem mass spectrometry (LC/MS/MS). This proposed technique could be applied to routine residue analysis.     

Validation of a dissociation enhanced lanthanide fluorescence immunoassay for the screening of 17beta-estradiol in bovine serum according to European Union decision 2002/657/EC

A validation study was carried out in order to evaluate the performances of a dissociation enhanced lanthanide fluorescence immunoassay (DELFIA) for rapid screening of 17 beta-estradiol in bovine serum. This validation was performed according to European Union (EU) Decision 2002/657/EC, which establishes criteria and procedures for determination of detection capability (CCbeta), selectivity/specificity, and applicability/ruggedness/stability for qualitative screening tests. To determine these performance characteristics, 20 blank serum samples of cattle were collected and spiked with 17 beta-estradiol at 40 pg/mL, corresponding to the maximum residue limit permitted by Italian legislation. According to the EU Decision CCbeta criterion, spiked samples must have <5% probability to be classified as a false negative. 17 beta-Estradiol was detected in each spiked sample, and the CCbeta results were <40 pg/mL. There was also no observed interference effect due to chemically related substances or from the matrix. Moreover, slight variations of some critical factors in the DELFIA procedure, deliberately introduced for ruggedness evaluation, did not result in any negative effect on the 17beta-estradiol detection. The proposed method is suitable for qualitative screening analysis of 17 beta-estradiol according to EU performance requirements.     

Rapid determination of fluoroquinolone residues in honey by a microbiological screening method and liquid chromatography

A rapid and efficient method was developed for the simultaneous determination of seven fluoroquinolone (FQ) residues: norfloxacin, ciprofloxacin, danofloxacin, enrofloxacin, orbifloxacin, sarafloxacin, and difloxacin in honey. The samples were first screened with a microbiological method by using test plates made from metal-free purified agar seeded with Bacillus subtilis BGA. When a sample was found to contain FQ residues by using the microbiological method, it was analyzed by LC with fluorescence detection (LC/FL). FQs were extracted with Na2EDTA-McIlvaine buffer and purified by a dual SPE method in which a cation-exchange cartridge was connected to an anion-exchange cartridge. The overall recoveries of the seven FQs ranged from 70.0 to 92.1%. The intra-assay and interassay CVs were < or = 7.8 and < or = 5.1%, respectively. For the microbiological method, the LOD values ranged from 2 to 9 microg/kg. For LC/FL, the LOQ values ranged from 2 to 7 microg/kg. The developed method was used to analyze 70 honey samples. In 14 samples in which the microbiological method detected the presence of FQ residues, norfloxacin, ciprofloxacin, and enrofloxacin were identified by LC/FL.     

超快速液相色谱-串联质谱法快速筛查蔬菜中176种农药的残留量

采用超快速液相色谱-串联质谱(UFLC-MS/MS)技术建立了蔬菜中176种农药残留快速筛查的分析方法。蔬菜样品采用乙腈提取,盐析后无需净化。采用多反应监测-信息关联采集-增强子离子扫描(MRM-IDA-EPI)的复合扫描模式,利用基于EPI谱图和色谱峰峰面积的谱库检索技术,完成了蔬菜中176种农药残留的定性定量分析。所有农药在各自的线性范围内线性关系良好(r＞0.99),除了丁硫克百威和灭蝇胺在3个添加水平下的平均回收率分别为46.8%和53.1%,其余174种农药的平均回收率范围为72.4%～126.4%,相对标准偏差范围为1.0%～18.7%,方法的检出限和定量限范围分别为0.005～2.0 μg/kg和0.1～10 μg/kg。该方法具有快速、灵敏度高、准确度高等优点,适合于蔬菜样品中农药多残留的快速筛查分析。     

Rapid screening procedure for the detection of trichothecenes in plasma and urine

A rapid and easy procedure to screen for trichothecenes in plasma and urine is presented. The toxins are extracted using a Clin-Elut column, hydrolyzed to their corresponding parent alcohols and cleaned up with a silica cartridge followed by derivatization for gas chromatographic analysis. The detection of any of the parent alcohols in plasma or urine would indicate an exposure to trichothecenes. Recoveries in urine are between 78 and 119% at levels of 50-1000 ng/ml and recoveries in plasma are between 80 and 116% at levels of 50-500 ng/ml. The limit of detection is better than 25 ppb.     

QuEChERS-液相色谱-质谱法快速筛查和确证大米中205种农药残留

结合QuEChERS法与液相色谱-三重四极杆复合线性离子阱质谱(LC-Q-TRAP/MS)技术,建立了大米中205种农药残留的快速筛查确证方法。大米样品经乙腈提取,N-丙基乙二胺(PSA)、无水MgSO₄和C₁₈吸附剂净化后,采用多反应监测-信息关联采集-增强子离子(MRM-IDA-EPI)扫描方式及谱库检索技术,通过对化合物的保留时间、离子对以及高灵敏度的EPI谱库检索比对,完成了205种农药的筛查与确证,并采用外标法定量,实现了大米样品中205种农药的定性和定量分析。结果表明,所有农药的线性相关系数均大于0.995;方法的定量限在0.5~10.0 μg/kg之间。在10、50 μg/kg两个添加水平下,205种农药的平均回收率在62.4%~127.1%之间;相对标准偏差(RSD)在1.0%~20.0%之间。该方法能够对大米样品进行实际检测,且检测时间不超过20 min。该方法快速、准确、灵敏度高,适合于大米中农药残留的快速、全面筛查和确证分析。     

超高效液相色谱-四极杆飞行时间质谱法非靶向快速筛查进口粮谷中未知的农药残留

利用快速提取农药(fast pesticide extraction,FaPEx)方法前处理样品,并结合超高效液相色谱-四极杆飞行时间质谱(UPLC-Q-TOF)技术建立了非靶向快速筛查进口粮谷中未知的多种农药残留方法。采用1%(v/v)醋酸乙腈溶液提取粮谷中未知的农药残留,FaPEx固相萃取柱净化、浓缩,UPLC-Q-TOF检测。利用目标化合物特征离子的精确质量数、同位素匹配、二级碎片信息和保留时间进行数据库匹配,筛查可疑未知农药。结果表明,该方法无需对照标准品即可快速筛查进口粮谷中的农药残留,能够应用于进口粮谷样品的实际筛查。该方法快速、准确、分析通量高,可以为进口粮谷中农药残留的快速筛查和质量控制提供重要的方法依据。     

Immunochemical screening for antimicrobial drug residues in commercial honey.

Honey samples (n = 100; origin: various countries from Eurasia, Oceania, and the Americas) were analysed by enzyme immunoassays (EIA) for tetracyclines, streptomycin, and sulfathiazole. Considering antibody specificity, these EIAs are either quantitative (streptomycin) or qualitative (tetracyclines, sulfathiazole) tests. Honey extract purification was achieved by liquid-liquid partition (tetracyclines), and by solid phase extraction-immunoaffinity chromatography (streptomycin, sulfathiazole). Detection limits were 20 micrograms kg-1 (tetracycline equivalents), 10 micrograms kg-1 (streptomycin), and 50 micrograms kg-1 (sulfathiazole equivalents), with mean recoveries of 100-117%. A total of 42% of the samples was found positive by EIA; 25% were positive in one assay, 13% in two, and 3% were positive in all three tests. In the EIA for tetracyclines, 26% were positive, with 12 samples exceeding a level of 50 micrograms kg-1 (tetracycline equivalents). In the EIA for streptomycin, 19% were positive, with a mean concentration of 19 +/- 12 micrograms kg-1. In the sulfathiazole EIA, 16% of the samples were positive, with 13 samples exceeding a level of 100 micrograms kg-1 (sulfathiazole equivalents). However, when samples which were positive in the sulfathiazole EIA were reanalysed for sulfonamides by HPLC, no sulfa drugs could be detected. Experimental heating (40 degrees C) of honey spiked with sulfathiazole indicated that the sulfa drug(s) responsible for positive EIA results could be present a sugar derivatives.     

Rapid screening of active ingredients in drugs by mass spectrometry with low-temperature plasma probe

A high-throughput method for rapid screening of active ingredients in drugs has been developed with mass spectrometry coupled to a low-temperature plasma (LTP) probe ion source. Without sample preparation or pretreatment, the active ingredients of 11 types of commercial pharmaceuticals, including hormones, antipyretic analgesics, cardiovascular, digestant, neuro-psychotherapeutic, diuretic, antithyroid, sulfa anti-inflammatory, antiparastic, sedative-hypnotics, and antibacterial, were directly desorbed/ionized and detected by a linear ion trap mass spectrometry (MS). The structures of these ingredients were elucidated by tandem MS. The analysis of 18 methyltestosterone tablets could be accomplished within 1.9 min, which allows fast detection with a speed of approximate 600 samples within 1 h. This work demonstrated that LTP probe ion source combined with MS is a high-throughput method for screening of pharmaceuticals and potentially applied to on-line quality control in pharmaceutical industry.

液相色谱-四极杆-飞行时间质谱法快速筛查与确证紫甘蓝中415种农药残留

应用液相色谱-四极杆-飞行时间质谱(LC-QTOF/MS)建立了一次进样可同时对紫甘蓝中415种农药残留进行快速筛查和准确确证的分析方法。实验采用1%(v/v)醋酸乙腈溶液提取,无水硫酸镁和氯化钠进行盐析,ZORBAX SB-C18色谱柱(100 mm×2.1 mm, 3.5 μm)分离,以0.1%(v/v)甲酸水溶液(含5 mmol/L乙酸铵)-乙腈为二元流动相进行梯度洗脱,应用LC-QTOF/MS在电喷雾电离、全离子MS/MS(All Ions MS/MS)扫描正模式下进行检测,基质匹配外标法定量分析。通过优化全自动MS/MS采集模式(Auto MS/MS)和全离子MS/MS采集模式下的不同参数,得到每种采集模式下的最佳条件。然后在2种不同采集模式的最佳条件下对比,最终选取All Ions MS/MS采集模式。实验结果表明,采用所建立的分析方法可以准确定性和定量筛查紫甘蓝中415种农药残留,所有415种农药在各自的范围内线性相关系数(r²)均大于0.990,其中411种农药的筛查限(SDL)≤5 μg/kg, 413种农药的定量限(LOQ)≤10 μg/kg。在1倍、2倍和10倍LOQ添加水平下,农药的回收率分别为65.7%~118.4%、72.0%~118.8%和70.2%~111.2%,相对标准偏差分别为0.9%~19.7%、0.2%~19.9%和0.6%~19.9%。将该方法应用于2019年欧盟能力验证项目的紫甘蓝样品中未知农药残留筛查方法和定量方法考核样的检测,所有添加农药均被准确定性筛查和定量检测,没有假阳性和假阴性。结果表明,该方法快速、准确、可靠,适用于对紫甘蓝中多种农药残留的高通量定性筛查和准确定量,可以扩展到其他果蔬基质中多农残的高通量筛查。     

Determination of three nitroimidazole residues in poultry meat by gas chromatography with nitrogen-phosphorus detection.

A method was developed for the determination of the nitroimidazole compounds dimetridazole (DMZ), ronidazole (RNZ) and metronidazole (MNZ) by gas chromatography with nitrogen phosphorus detection. Nitroimidazole compounds were extracted with acetonitrile, followed by acidification using acetic acid and cleanup using strong cation-exchange (SCX) SPE column. Validation in chicken muscle fortified at a concentration of 5 microg/kg gave mean recoveries of 85% DMZ, 90% RNZ, 80% MNZ with RSDs of 13.0, 14.3, 11.2%, respectively (n=6). The method is suitable for statutory residue testing and is used as a quick screening method in the National Residue Surveillance Plan in China.     

Rapid determination of chloramphenicol residues in aquaculture tissues by immunochromatographic assay.

An immunochromatographic assay was developed to detect chloramphenicol (CAP) residues in aquaculture tissues. The limit of detection (LOD) was 10 ng g(-1) for detecting CAP spiked in the aquaculture tissues. The results were confirmed by liquid chromatography tandem mass spectrometry (LC/MS/MS) and indicated that there was a good agreement between the two methods. The linear regression equation was y = 1.19x + 0.539 with R(2) = 0.978. The assay time for test was less than 5 min and the method is suitable for rapid testing on-site.     

Sin-QuEChERS Nano净化柱结合气相色谱-串联质谱法快速筛查石斛中84种农药残留北大核心CSCD

利用Sin-QuEChERS Nano净化柱结合气相色谱-串联质谱(GC-MS/MS)分析,建立了石斛基质中84种不同极性农药残留的快速筛查方法。比较了采用不同的提取溶剂(1%乙酸乙腈、丙酮)和不同的提取方式(加水浸泡和不加水浸泡)下目标物的提取效率。利用金钗石斛样品系统比较了Sin-QuEChERS Nano法与经典的基质固相分散法(dSPE)、固相萃取法(SPE)、QuEChERS法的净化效果及提取回收率,以及净化效果较好的Sin-QuEChERS Nano法与dSPE法基质效应的差异。目标物经DB-1701MS石英毛细管色谱柱(30 m×0.25 mm×0.25μm)程序升温分离,GC-MS/MS多反应监测(MRM)模式检测,基质匹配溶液外标法定量。通过GC-MS/MS检测方法对金钗石斛和铁皮石斛中的84种代表性农药进行了方法学验证。结果表明:各目标物在不同范围内呈良好的线性相关,相关系数(r^(2))均>0.990,方法的检出限(LOD,S/N=3)为1.5~5.8μg/kg,方法的定量限(LOQ,S/N=10)为5.0~15.0μg/kg。在两个水平下,目标农药的加标回收率为68.7%~116.2%,相对标准偏差(RSD,n=6)均低于15%。与其他经典的前处理方法相比,Sin-QuEChERS Nano法在净化效果方面表现更好,该法不仅可以有效去除色素、有机酸、碱性干扰物等物质,还可以节省样品制备时间,避免溶剂转移造成的损失,无需进一步涡旋或离心,是一种简单而有效的提取物纯化程序。该方法灵敏、快速、简便、可靠,有效地提高了石斛中农药快速筛查时的检测效率,具有较强的实际应用价值。此外,所开发的方法可以进一步扩展目标农药的类型,并可以用于检测其他更多食品及中药材中的农药残留。     

9-Fluoreneacetyl-tagged, solid-phase reagent for derivatization in direct plasma injection.

We describe here a resin-based derivatization reagent, containing a 9-fluoreneacetyl tag on a controlled-pore substrate, for direct injection analysis of amphetamine in plasma. On-line, pre-column derivatization was performed by direction injection of diluted plasma sample into an sodium dodecyl sulfate-containing mobile phase. Amphetamine was trapped in the hydrophobic derivatization column and derivatized at elevated temperature by the activated solid-phase reagent. The derivatized 9-fluoreneacetyl amphetamide was separated by reversed-phase high-performance liquid chromatography with a step gradient and determined by fluorescence detection. The synthesis scheme, characterization, and optimization of the derivatization conditions for the solid-phase reagent are described. The method was evaluated by reproducibility tests and single blind spiking analysis. This solid-phase reagent combined with a surfactant containing mobile phase provided a sensitive and simple procedure for on-line derivatization in direct injection analysis of biological fluids.     

气相色谱-四极杆-飞行时间质谱法快速筛查食品中182种农药残留

建立了气相色谱-四极杆-飞行时间质谱同时筛查食品中182种香港《食物内残余除害剂规例》农药残留的分析方法。样品经含0.1%（v/v）甲酸的乙腈溶液提取,改进的QuEChERS方法净化,采用Agilent HP-5MS色谱柱（30 m×0.25 mm×0.25 μm）进行分离。样品经电子轰击源电离,一级质谱采用全扫描模式完成化合物的定性和定量检测,对疑似物质进行二级谱库检索确证。考察了10种典型食品基质（大米、香菇、黄豆、菠菜、西红柿、西兰花、柚子、胡萝卜、生菜、黄瓜）的基质效应。在10~500 μg/kg范围内,182种目标化合物的线性关系良好（r>0.99）,方法的定量限（S/N≥10）为10~100 μg/kg,在3个添加水平下的平均加标回收率分别为66.1%~121.5%、75.4%~125.8%、77.2%~128.9%,相对标准偏差（RSD）为0.8%~17.6%（n=6）。该方法操作简单、耗时短、灵敏度高、稳定性好,可显著降低日常筛查检测的成本,具有实际应用价值。     

气相色谱-串联质谱法快速筛查测定中药材中144种农药残留

利用气相色谱-串联质谱(GC-MS/MS)检测技术,采用QuEChERS法作为样品前处理方法,建立了能应用于11种中药材中144种农药残留的检测方法。探究了样品前处理过程中提取溶剂、缓冲盐体系、净化剂组成和用量对样品提取、净化等方面的影响,最终确定了用乙腈提取,甲苯复溶,以混合净化剂净化,过有机膜后经GC-MS/MS测定,外标法定量。144种农药在10~2000 μg/kg之间线性关系良好,相关系数(r²)>0.983;除乙酰甲胺磷、灭虫威、西玛津、克菌丹、异狄氏剂、异菌脲外,其余农药的定量限(LOQ)均低于20 μg/kg;在20、50、200 μg/kg的添加水平下,除乙酰甲胺磷、艾氏剂和双甲脒回收率偏低外,其余141种农药的平均回收率在74.3%~111.8%之间,相对标准偏差(RSD)为0.5%~14.6%。与已有的标准方法对比,此方法不仅检测结果一致,而且高效、快速,准确性好,灵敏度高,适用于中药材中144种农药残留的快速筛查与定量分析。     

Rapid determination of propyphenazone in plasma by high-performance liquid chromatography.

A rapid and simple high-performance liquid chromatographic assay for the determination of propyphenazone in plasma is described. Phenylbutazone was used as the internal standard. Plasma proteins were precipitated with acetonitrile before injection onto a 3-microns Supelcosil LC-18 column. The mobile phase, ethanol containing 0.2% (v/v) heptylamine-0.005 M potassium dihydrogenphosphate (30:70, v/v), was used at a flow-rate of 1.3 ml/min. The quantitation was performed by ultraviolet detection at a wavelength of 270 nm. The chromatographic time was 7 min. The within- and between-day coefficients of variation were less than 6% and the recoveries close to 100% for concentrations between 0.4 and 22 mumol/l. The limit of quantitation was 0.4 mumol/l (ca. 100 ng/ml).     

Rapid screening method for methamphetamine in urine by colour reaction in a Sep-Pak C18 cartridge

A simple screening method for methamphetamine in urine by colour reaction was developed. Methamphetamine, which is quantitatively retained in a Sep-Pak C18 cartridge, is (after a clean-up procedure) coloured by Simon's reagent (consisting of sodium nitroprusside solution, sodium carbonate solution and acetaldehyde gas). The detection limit was 0.5 microgram/ml using 5 ml of urine sample. The results of the screening method agreed with those of thin-layer chromatography and gas chromatography-mass spectrometry.