Effect of cooking on enrofloxacin residues in chicken tissue

The aim of this study was to determine the effect of different cooking processes (microwaving, roasting, boiling, grilling and frying) on naturally incurred enrofloxacin residues in chicken muscle. Enrofloxacin and its metabolite, ciprofloxacin, were analysed using a validated LC-MS method with limits of detection (LOD) and quantification (LOQ), respectively, of 2 and 5 ng g^-1 quinolones in muscle samples. The method was shown to be linear over the range 5-500 ng g^-1. Mean intra-day relative standard deviation (RSD) at a concentration of 50 ng g^-1 (n = 6) was 6%; inter-day RSD was 12%. A recovery study demonstrated that 65-101%, of the drug and metabolite could be recovered from the tissue. The RSD with naturally incurred roasted chicken breast was 9.18% at a concentration of 11 ± 1.01 ng g^-1 (n = 6). In water, enrofloxacin remained stable for 3 h when heated at 100°C. It was concluded that residue data from raw tissue are valid for estimation of consumer exposure to this drug, as well as the ADI calculations because cooking procedures did not affect enrofloxacin residues, which remained stable during heating. However, there was an apparent decrease in quinolone concentration in tissue because some was lost by exudation into the liquid used for cooking. Conversely, for a cooking procedure with water loss, there was an apparent increase in residue concentration.     

酶联免疫法与液相色谱-串联质谱法检测猪肉中沙丁胺醇

运用酶联免疫法（ELISA）与液相色谱-串联质谱法（LC-MS/MS）对猪肉中沙丁胺醇残留进行测定,并比较了二者在灵敏度、准确性和重现性等方面的差异。结果显示,ELISA法和LC-MS/MS法在猪肉样品中的检测限可达到0.5 μg/kg和0.25 μg/kg,分别向猪肉样品中添加3个质量浓度水平（1.0 μg/kg、2.0 μg/kg、4.0 μg/kg）的沙丁胺醇时,回收率分别为83.7%～90.9%和86.6%～93.5%,变异系数（CV）分别为5.4%～10.3%和6.0%～8.3%。用酶联免疫法实际样品进行检测,筛选出2个阳性样品,经液相色谱-串联质谱法确证亦为阳性,测定结果一致。研究表明,酶联免疫法重复性较好、准确度较高,适用于进行猪肉样品中沙丁胺醇的快速筛选,液相色谱-串联质谱法适用于阳性样品的确证和精确定量。     

HPLC-MS/MS测定猪肉和猪肝中氯霉素残留量的研究

建立高效液相色谱-串联质谱法(HPLC-MS/MS)检测猪肉和猪肝中氯霉素药物残留的分析方法。样品经4%的氯化钠溶液和乙腈提取并沉淀蛋白质,正己烷脱脂净化,乙酸乙酯液液萃取,再浓缩定容,上HPLC-MS/MS仪器,用Syncronis C18柱分离,以乙腈-水(40∶60)作为流动相,采用电喷雾离子源(ESI),负离子模式,多反应监测(MRM)方式检测,用氯霉素-D5作内标物来定量。在该试验条件下,氯霉素在1～15ng/mL浓度呈良好的线性关系,r=0.999 2,最低检出浓度为0.1μg/kg,样品的加样回收率在90.0%～110.0%,重复性好RSD<3.0%。该方法能对猪肉和猪肝中氯霉素残留进行定性及定量分析,方法精密度较好、准确度较高、选择性好,结果满意。     

Development and validation of multi-residue method for determination of 412 pesticide residues in cotton fiber using GC-MS/MS and LC-MS/MS

The new global concept is to care about textiles and clothes safety to improve the protection of the human health and the environment from the harmful pesticide residues. Very few articles have been published for determination of several pesticide classes in cotton fibers in one multi-residue method. A simple, efficient, sensitive, accurate, and reliable multi-residue method was developed for the determination of 412 residual pesticides in cotton fibers using modified QuEChERS method with Liquid and Gas Chromatography coupled to Triple Quadrupole Mass Spectrometer (LC-MS/MS &; GC-MS/MS) for qualitative and quantitative analysis according to the international standards concepts. The developed method covered several pesticide classes, including 43 carbamates, 16 pyrethroids, 27 organochlorines (OCs), 54 organophosphorus (Ops), 31 urea derivatives, 7 Polychlorinated biphenyl (PCBs), 6 Neonicotinoid, and 228 other pesticides. Most of the target pesticides were listed in Oeko-Tex Standards, the EU Ecolabel for textile products, and the Egyptian recommendations of the Agricultural Pesticide Committee (APC-Egypt). The method optimization and validation were carried out according to the EU guidelines. The results were shown to be reliable where the corresponding average recoveries within the acceptable range of 70–120%; the relative standard deviations were less than 20%. The limit of quantitation (LOQ) of this method is 0.01 mg kg^?1 all pesticides except for 3 GC-compounds and 19 LC-compounds which have LOQ of 0.05 mg kg^?1.     

Determination of halosulfuron-methyl residues and dissipation in wheat by QuEChERS and LC-MS/MS

A sensitive and rapid analytical method based on QuEChERS (quick, easy, cheap, effective, rugged and safe) sample preparation and LC-MS/MS detection was developed for the analysis of halosulfuron-methyl residues in wheat. The recoveries of halosulfuron-methyl in both the wheat plant and grain ranged from 87% to 119% and from 75% to 97%, respectively, with relative standard deviations (RSDs) of 3–9%. The limit of quantification (LOQ) was 0.005 mg kg^?1 for wheat plant and 0.001 mg kg^?1 for wheat grain. The half-life of halosulfuron-methyl in the wheat plant was 0.9–9.5 days. The terminal residue levels of halosulfuron-methyl in wheat grain were below 0.01 mg kg^?1 at harvest.     

Interference of mycotoxin binders with ELISA,HPLC and LC-MS/MS analysis of aflatoxins in maize and maize gluten

ABSTRACT

The aim of this study was to investigate the impact of mycotoxin binders on the determination of aflatoxins in maize and maize gluten using various analytical methods, including ELISA, HPLC and LC-MS/MS. Three types of commercially available mycotoxin binders, yeast cell wall, mineral, and a mixture of mineral and bacterium, were investigated at inclusion levels of 0.1%, 0.2% and 0.4%. The binders were added to maize and maize gluten contaminated with aflatoxins at concentrations between 6.9 and 26.7 μg kg^?1. The samples were analysed and the values were compared with corresponding controls (samples without binders) using ANOVA. The yeast cell wall binder had no significant effect (p=0.05) on the concentration of aflatoxins measured in either maize or maize gluten at any of the three inclusion levels, regardless of which analytical method was used. The mineral binder and the mixed mineral and bacterium binder had no significant effect (p=0.05) on the measured aflatoxin concentrations in either maize or maize gluten at any of the three inclusion levels when analysis was conducted using LC-MS/MS. Inclusion of these binders resulted in significant lower (p<0.01) detection of aflatoxins in both maize and maize gluten when analysis was conducted using ELISA; the effect was dose-dependent. They also resulted in significant lower detection of aflatoxins in maize extracted by methanol/water (70/30 v/v) (p<0.0001) and in maize gluten extracted by acetonitrile/water (80/20 v/v) (p<0.05) when analysis was conducted using HPLC. However, neither the mineral binder nor the mixed mineral and bacterium binder had significant effects (p=0.05) on aflatoxin concentrations measured in maize using HPLC, when extracted by acetonitrile/water (80/20 v/v). The study demonstrated that mycotoxin binders could result in underestimation of the levels of aflatoxin contamination, depending on the nature of the binder, the extraction solvent used in the analytical method, and the composition of tested sample.     

直接竞争酶联免疫法测定西维因残留

采用快速直接竞争酶联免疫法检测苹果、梨、小油菜、大米和大麦中的西维因残留,并以高效液相法进行验证。高效液相色谱法和酶联免疫法所得结果的相关性很好,相关系数大于0.8。同时研究了一种简单、快速并有效的提取方法——2min匀浆法,样品回收率超过90%。选用苹果、梨、小油菜、大米和大麦5种不同的样品,通过实验排除了5种基质对酶联免疫分析方法的影响。根据本研究,进一步开发并制成检测西维因残留的试剂盒,可用于大量样品的快速现场检测。     

HPLC-MS/MS法检测鸡肉食品中金刚烷胺残留

采用HPLC-MS/MS法对鸡肉食品中金刚烷胺的残留进行了检测分析.结果显示,在103份待测样品中19份检测到金刚烷胺残留,其在鸡肝、鸡翅、鸡腿中的残留量分别为5.5、32.6～92.4、11.4～25.3μg/kg,而在鸡胸肉中未有检出.上述结果表明,鸡体的不同部位所含金刚烷胺的残留量不尽相同,同时也表明,在鸡养殖行业内还部分地存在金刚烷胺的违规使用现象,有必要对该违规行为作进一步的监管.     

QuEChERS-UPLC-MS/MS同时测定鸡肉中80种兽药残留

目的:建立一种同时测定鸡肉中包括喹诺酮类、磺胺类、β-受体激动剂类、糖皮质激素类、大环内酯类、抗病毒类药物、四环素类等在内的80种兽药的QuEChERS-超高效液相色谱—串联质谱法(UPLC-MS/MS)分析方法。方法:样品经1%甲酸乙腈水溶液提取,QuEChERS多兽药残留净化柱净化,超高效液相色谱—串联质谱(UPLC-MS/MS)多反应监测模式检测,基质标准曲线外标法定量。结果:80种兽药在特定质谱条件下响应性高,样品在质谱检测条件下检测灵敏,无杂峰干扰。80种药物质量浓度在5.0～100μg/L的范围内,线性关系良好,相关系数均大于0.99。80种兽药的方法检出限均为1.0μg/kg。样品中2.0,5.0,10.0μg/kg加标浓度的平均回收率为62.2%～106.8%,相对标准偏差为2.07%～10.85%。结论:80种药物在样品中加标回收率均符合GB/T 27404—2008《实验室质量控制规范食品理化检测》标准要求,适用于鸡肉中80种兽药残留的筛查测定。     

Simultaneous determination of residues of trichlorfon and dichlorvos in animal tissues by LC-MS/MS

Trichlorfon is a thermally unstable insecticide that can be easily decomposed to dichlorvos at high temperatures. In this study, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for simultaneous determination of the residues of trichlorfon and dichlorvos in animal tissues. Trichlorfon and dichlorvos in animal tissues were extracted with dichloromethane, homogenized/shaken, concentrated, and determined by LC-MS/MS. The two insecticides can be effectively separated and individually determined. The limits of detection (LODs) of trichlorfon and dichlorvos were 0.04 and 0.07 µg kg^?1, respectively; the limits of quantification (LOQs) of the two insecticides were both 5 µg kg^?1. The average recoveries for three spiked blank samples at 10, 20 and 40 µg kg^?1 were in the range 85–106%, with relative standard deviations (RSDs) below 10.6%, which falls in a reasonable range for the analysis of the two insecticides in animal-derived foods. The method is fit-for-purpose for the simultaneous determination of residues of trichlorfon and dichlorvos in animal tissues.     

鳗鱼中恩诺沙星残留量的酶联免疫检测方法

运用酶联免疫分析方法测定鳗鱼中恩诺沙星残留。测试曲线线性范围为0.3～10μg/kg,最低检测限为3μg/kg。向样品中分别添加25、50、100μg/kg 3个浓度水平的恩诺沙星, 平均回收率分别为74.5%、76.6%和66.5%,批内变异系数为7.62%～14.31%,批间变异系数为6.03%～7.00%,灵敏度达到0.3μg/kg。特异性试验结果表明与喹诺酮类中的其它药物以及其它类抗生素均无交叉反应。     

广州市场活鸡盐酸克仑特罗残留调查

建立并运用酶联免疫法直接测定家禽组织盐酸克仑特罗含量,调查了广州市场6种活鸡鸡肉及鸡肝中盐酸克仑特罗含量。结果表明:6种活鸡鸡肉及鸡肝中盐酸克仑特罗含量为155.27±81.17～322.00±127.56ng/kg,符合残留低限,平均回收率为94.30%,酶联免疫法可快速、准确测定家禽组织中盐酸克仑特罗含量。     

基于QuEChERS的UHPLC-MS/MS同时检测鸡蛋中19种农药残留量

目的：构建一种同时、快速、高效的检测鸡蛋中多种农残方法。方法：将QuEChERS与UHPLC-MS/MS结合用于鸡蛋中19种农药残留量的检测。结果：所建方法的检出限（LOD）和定量限（LOQ）分别为（0.39±0.66）,（1.28±2.17） μg/kg;加标回收率为79.25%～102.14%,相对标准偏差均值（RSD）为9.34%～16.72%;除恶唑菌酮外,鸡蛋中其余18种农药的线性相关系数接近0.999。所测鸡蛋中鸡蛋中19种农残检出总频率为2.82%,农残问题主要涉及辛硫磷和毒死蜱,其检出频率分别为22%,15%,浓度范围分别为2.08～729.74,0.81～46.89 μg/kg。结论：所建方法准确可靠,符合相关检测要求;湖北省境内鸡蛋中农残检出频次低、安全隐患较小。     

氨基甲酸酯类农药残留检测方法对比研究

目前蔬菜中氨基甲酸酯类农药残留普遍采用液相色谱柱后衍生法(HPLC)进行测定,研究液相色谱- 质谱法(LC-MS/MS)测定蔬菜中7 种常用氨基甲酸酯类农药,并与高效液相色谱柱后衍生法进行比较。液相色谱柱后衍生法是经典方法,重现性好,但是检测周期长,衍生试剂价格昂贵且稳定性差;LC-MS/MS 法保留时间短,灵敏度高,操作简便,实验过程快,是氨基甲酸酯类农药检测发展的方向。     

酶联免疫法与LC-MS/MS法测定水产品中呋喃唑酮代谢物

运用酶联免疫法和LC-MS/MS法对水产品中呋喃唑酮代谢物残留进行测定.样品经2-硝基苯甲醛衍生化并用乙酸乙酯提取.向样品中分别添加0.60、2.00、6.00μ g/kg三个浓度水平的呋喃唑酮代谢物时,酶联免疫法平均回收率分别为99.2%、96.0%和100.0%,变异系数(RSD)为1.8%～12.6%,最低检测限为0.3μg/kg.LC-MS/MS法平均回收率分别为90.8%、94.3%和86.3%,RSD为6.2%～14.3%,最低检测限为0.1μg/kg.用酶联免疫法对150个样品进行检测,筛选出3个阳性样品,经LC-MS/MS确证为阳性,未发现假阳性样品,且测定结果基本一致.研究表明酶联免疫法重复性较好、准确度较高,是一种水产品中呋喃唑酮代谢物残留的快速筛选方法;液- 质/质联用法灵敏度高,适用于阳性样品的确证和精确定量.     

Microbiological and chemical detection of incurred penicillin G, oxytetracycline, enrofloxacin and ciprofloxacin residues in bovine and porcine tissues

Incurred penicillin G, oxytetracycline, enrofloxacin and ciprofloxacin residues in bovine and porcine muscle and kidney samples were analysed by microbiological and chemical methods, the former using Bacillus subtilis BGA as a test organism on agar media of pH 6, pH 7.2 and pH 8 and the latter using liquid chromatography. Least squares fits between the logarithms of the chemically obtained concentrations of the antimicrobials and the widths of the inhibition zones were used to estimate the inhibition zone widths corresponding to the maximum residue limit concentrations. In vitro sensitivities were determined with standard antimicrobial solutions. The results indicate that if B. subtilis BGA is used as a test organism, muscle tissue cannot be used as test material for screening oxytetracycline, enrofloxacin and ciprofloxacin residues on the plates used in this study, while penicillin G can be screened from muscle tissue. Because of the numerous factors causing or increasing variation in the analysis, the inhibition zone caused by a given antibiotic concentration cannot be predicted precisely. Therefore, a positive agar diffusion test needs to be confirmed chemically. If a kidney sample gives a positive agar diffusion test result, the antimicrobial concentration in a muscle sample from the same carcass should be checked chemically.     

Determination of chloramphenicol residues in commercial chicken eggs in the Federal Capital Territory,Abuja, Nigeria

The use of antibiotics in poultry can result in residues in eggs. The joint FAO/WHO committee recommended banning the use of chloramphenicol (CAP) in food animals due to its public health hazards of aplastic anaemia, leukaemia, allergy, antibacterial resistance and carcinogenicity. This paper determines the prevalence of CAP residues in chicken eggs and assesses the usage and awareness of its ban amongst poultry farmers in the Federal Capital Territory (FCT), Abuja, Nigeria. A cross-sectional survey of registered poultry farmers in FCT was conducted using questionnaires to determine CAP administration in poultry and awareness of its ban. Pooled egg samples were collected from each poultry farm surveyed and from randomly sampled government-owned markets in FCT. Source of eggs by state were identified by the marketer at the time of collection. Samples were analysed using an enzyme-linked immunosorbent assay (ELISA) technique for the presence of CAP, and prevalence was determined. Of 288 total pooled samples collected, 257 (89.2%) were from the markets and 31 (10.8%) were from poultry farms. A total of 20 (7%) pooled egg samples tested CAP-positive; market eggs originated from 15 (41%) states of the country. Of the market eggs, 16 (6.2%) pooled samples tested positive. Of eggs from poultry farms, four (12.9%) tested positive. Mean CAP concentrations in the positive samples ranged from 0.49 to 1.17 µg kg^?1 (parts per billion). CAP use amongst poultry farmers in FCT was 75.5%; awareness of the CAP ban was 26.3%. Though 66% of veterinarians were unaware of a CAP ban, they were more likely to be aware than other poultry farmers (odds ratio (OR) = 1.4). Farm managers who use CAP were more likely to be aware of CAP ban than the farm managers not using CAP (OR = 5.5; p = 0.04). Establishing a drug residue surveillance and control program and enforcement of CAP legislation/regulation is needful to educate and prohibit the widespread CAP use amongst Nigerian poultry farmers.     

Simple detection of residual enrofloxacin in meat products using microparticles and biochips

A simple and sensitive method for detecting enrofloxacin, a major veterinary fluoroquinolone, was developed. Monoclonal antibody specific for enrofloxacin was immobilised on a chip and fluorescent dye-labelled microparticles were covalently bound to the enrofloxacin molecules. Enrofloxacin in solution competes with the microparticle-immobilised enrofloxacin (enroMPs) to bind to the antibody on the chip. The presence of enrofloxacin was verified by detecting the fluorescence of enrofloxacin-bound microparticles. Under optimum conditions, a high dynamic range was achieved at enrofloxacin concentrations ranging from 1 to 1000 μg kg^?1. The limits of detection and quantification for standard solutions were 5 and 20 μg kg^?1 respectively, which are markedly lower than the maximum residue limit. Using simple extraction methods, recoveries from fortified beef, pork and chicken samples were 43.4–62.3%. This novel method also enabled approximate quantification of enrofloxacin concentration: the enroMP signal intensity decreased with increasing enrofloxacin concentration. Because of its sensitivity, specificity, simplicity and rapidity, the method described herein will facilitate the detection and approximate quantification of enrofloxacin residues in foods in a high-throughput manner.     

高效液相色谱法测定鸡肉中恩诺沙星和环丙沙星残留的不确定度分析

建立高效液相色谱法测定鸡肉中恩诺沙星和环丙沙星残留的不确定度评定方法。建立数学模型,依据JJF1059-1999《测量不确定度评定与表示》和CNAS-GL06《化学分析中不确定度的评估指南》规定的基本方法和程序,对测量过程中各不确定度分量进行分析和计算,最后给出合成标准不确定度和扩展不确定度。结果表明,不确定度主要来源于标准曲线的拟合和样品处理的过程。      

ELISA法与LC-MS/MS法测定动物组织中克仑特罗残留

目的:比较酶联免疫法(ELISA)和液相色谱-串联质谱法(LC-MS/MS)测定动物组织中克仑特罗残留量的准确度、精密度及检测限。方法:样品经过处理后,分别采用ELISA法和LC-MS/MS法进行测定;用ELISA法对组织样品进行初筛,测出阳性样品利用LC-MS/MS法进行确证。结果:应用ELISA法测定样品猪肉样品中克仑特罗的回收率为67.0%～99.6%,批内变异系数3.4%～8.7%,批间变异系数6.1%～9.6%,灵敏度为0.025μg/L,最低检测限0.025μg/kg;LC-MS/MS检测方法回收率88.62%～111.43%,批内变异系数4.4%～7.4%,最低检测限0.5μg/kg;用ELISA法对50份猪肉和50份猪肝样品进行检测,筛选出3个阳性样品,经LC-MS/MS确证为阳性,两种方法检测结果一致。结论:ELISA法灵敏度和准确度较高,样品处理方法简单,成本低,适合组织中克仑特罗残留大规模筛查;LC-MS/MS准确度高,适合于阳性样品精确定量。