超高效液相色谱-串联质谱法测定果蔬中氟啶虫胺腈、Pyrifluquinazon和螺虫乙酯残留量

建立超高效液相色谱-串联质谱同时测定蔬菜和水果中氟啶虫胺腈、Pyrifluquinazon和螺虫乙酯残留量的分析方法。样品经乙腈均质提取,混合使用乙二胺-N-丙基硅烷和十八烷基硅烷基质分散净化剂净化,以C18色谱柱分离待测物,采用电喷雾离子化,正离子扫描和动态多反应监测模式检测,基质匹配标准溶液外标法定量。氟啶虫胺腈在0.2～100?μg/L之间,Pyrifluquinazon在0.02～10?μg/L之间,螺虫乙酯在0.1～10?μg/L之间的范围内线性关系良好,相关系数均大于0.999?0。在4个添加水平进行氟啶虫胺腈、Pyrifluquinazon和螺虫乙酯添加回收率实验,平均添加回收率在79.9%～103.9%之间,相对标准偏差在3.3%～8.8%之间。氟啶虫胺腈、Pyrifluquinazon和螺虫乙酯的方法定量限分别为0.334、0.040?5?μg/kg和0.378?μg/kg,检出限分别为0.100、0.012?2?μg/kg和0.133?μg/kg。该方法快速简便、定量准确,可满足多种蔬菜和水果中氟啶虫胺腈、Pyrifluquinazon和螺虫乙酯3?种杀虫剂的残留检测要求。     

七种杀虫剂对烟蚜和南方小花蝽的毒力测定

为筛选出对南方小花蝽安全的药剂,测定了烟田常用7种杀虫剂对烟蚜成蚜（浸渍法）的毒力及南方小花蝽5龄若虫、雌成虫（药膜法）的毒性,并对南方小花蝽进行了安全性评价。结果表明,无论处理24 h还是48 h,对烟蚜成蚜的毒力、南方小花蝽雌成虫的毒性均是啶虫脒最高,LC₅₀分别为0.258和0.027 mg/L（24 h）、0.164和0.019 mg/L（48 h）,苦参碱最低,LC₅₀分别30.224和28.396 mg/L（24 h）、17.106和9.334 mg/L（48 h）;对南方小花蝽5龄若虫的毒性以溴氰菊酯最高,吡虫啉最低,苦参碱和阿维菌素相当,仅大于吡虫啉。综合考虑毒性和安全系数,防治烟蚜时选用苦参碱和阿维菌素能更好的保护南方小花蝽,达到协调化学防治和生物防治的目的。     

QuEChERS-超高效液相色谱-串联质谱法测定柑橘中呋虫胺和螺虫乙酯残留量

目的建立QuEChERS-超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)同时测定柑橘中咲虫胺及螺虫乙酿残留量的分析方法。方法样品采用QuEChERS方法,经1%甲酸乙腈涡旋振荡提取,无水硫酸镁和氯化钠盐析后,经乙二胺-N-丙基硅烷、C_(18)混合净化剂净化,用Waters ACQUITY UPLC HSS T_3色谱柱分离,超高效液相色谱-串联质谱正离子扫描、多反应监测模式进行测定,外标法定量。结果呋虫胺及其代谢物、螺虫乙酯及其代谢物在相关浓度范围内线性关系良好,相关系数均大于0.99。呋虫胺及其代谢物的回收率为86.8%～97.6%,相对标准偏差为2.7%～6.8%,方法定量限为0.005～0.01 mg/kg;螺虫乙酯及其代谢物的回收率为85.8%～96.9%,相对标准偏差为3.2%～7.4%,方法定量限为0.005～0.008 mg/kg。结论该方法样品前处理过程简单快速,分析时间短,定量限低、正确度及精密度均符合农药残留检测要求,适用于同时测定柑橘中呋虫胺和螺虫乙酯残留。     

5种生物农药对烟蚜和食蚜瘿蚊的毒力测定及安全性评价

为筛选出对食蚜瘿蚊安全的生物农药,选用5种常用的生物农药对烟蚜及食蚜瘿蚊幼虫（喷雾法）和食蚜瘿蚊成虫（药膜法）进行了毒力测定和安全性评估。结果表明,无论处理24 h还是48 h,对烟蚜毒力较高的是甲维盐和苦参碱,LC₅₀分别为2.166和3.695 mg/L（24 h）,1.567和2.874 mg/L（48 h）;对食蚜瘿蚊幼虫的毒力较高的是鱼藤酮,LC₅₀为18.137 mg/L（24 h）、13.771 mg/L（48 h）,对成虫的毒力较高的是多杀菌素,LC₅₀为7.249 mg/L（24 h）、4.125 mg/L（48 h）。因此5种生物农药中苦参碱、甲维盐、苏云金杆菌对烟蚜和食蚜瘿蚊的选择性较高,适宜在田间与食蚜瘿蚊联合应用防控烟蚜。     

药剂混配对B型烟粉虱药效及烟草安全性评价

利用试管药膜法测定了啶虫脒等药剂及其混配对B型烟粉虱成虫的毒力,利用烟草植株测定了哒螨灵、啶虫脒及混配对B型烟粉虱的药效以及对烟草植株的安全性.结果显示,啶虫脒在3种新烟碱类药剂中显示了较高毒力,LC50为7.119 5mg/L,哒螨灵与啶虫脒1:1与2:1混配显示了一定的拮抗作用,4:1与8:1混配显示出了一定的相加...     

螺虫乙酯单克隆抗体的制备及酶联免疫分析方法的建立

螺虫乙酯是一种杀虫杀螨剂,它通过抑制乙酰辅酶A羧化酶活性,阻断害虫正常的能量代谢,最终致其死亡。由于其作用高效,被广泛应用于防治果蔬中的刺吸口器类害虫和害螨。然而,螺虫乙酯对人和动物有毒性。该研究旨在通过制备螺虫乙酯的单克隆抗体并建立酶联免疫分析方法实现蔬菜、水果和环境样品中螺虫乙酯残留的快速检测。首先设计合成了一种新型的螺虫乙酯半抗原,通过活泼酯法偶联牛血清白蛋白得到免疫原,免疫小鼠筛选得到特异性识别螺虫乙酯和B-enol的单克隆抗体（mAb 3D11G7）。在优化的条件下,建立间接竞争酶联免疫分析方法（indirect homologous competitive enzyme-linked immunosorbent assay, icELISA）,其半数抑制质量浓度(half maximal inhibitory concentration, IC₅₀)值为2.1μg/L,最佳工作范围为0.5～8.6μg/L。选择河水、土壤、番茄和柑橘基质进行加标回收实验,其平均加标回收率为72.9%～110.1%。该研究建立的icELISA与超高效液相色谱-串联质谱测定...     

哒螨灵、吡蚜酮对B型烟粉虱的毒力测定和药效试验

采用闪烁管药膜法和叶片浸渍法分别测定了哒螨灵等药剂对B型烟粉虱成虫和若虫的毒力,结果表明:杀螨剂哒螨灵对烟粉虱成虫有优异的触杀毒力,LC50为0.9517 mg/L,毒力效果好于阿维菌素,吡虫啉、灭多威、毒死蜱等防治烟粉虱的常用药剂作用效果已不理想;若虫毒力效果显示吡蚜酮对烟粉虱3龄若虫的毒力效果最佳,LC50为0.9571 mg/L,新烟碱类杀虫剂效果好于有机磷类和氨基甲酸酯类杀虫剂,但均明显低于吡蚜酮;以哒螨灵与吡蚜酮的混配制剂模拟田间药效试验,结果显示其对B型烟粉虱有好的防效,是防治烟粉虱的良好替代药剂。     

螺虫乙酯及其代谢物在番茄中的储藏稳定性

目的建立超高效液相色谱-串联质谱法测定番茄样品中螺虫乙酯及其代谢产物残留的分析方法,考察螺虫乙酯及其代谢产物在番茄中的储藏稳定性。方法低温储藏0～274 d的番茄样品经乙腈提取,采用NaCl和无水MgSO4除水,离心过膜后的上清液经超高效液相色谱-串联质谱测定,基质匹配标准溶液外标法定量。结果螺虫乙酯及其4种代谢产物在0.001～0.5mg/L范围内线性关系良好,在0.02、0.1、1和5mg/kg添加水平的平均回收率为75.1%～104.5%,相对标准偏差小于11.93%(n=5)。番茄样品在–18℃储藏条件下螺虫乙酯、螺虫乙酯烯醇、螺虫乙酯羟基、螺虫乙酯醇酮的平均降解率均小于30%,螺虫乙酯烯醇糖苷在储藏274 d时降解率大于30%(平均降解率53.3%)。结论–18℃条件下螺虫乙酯、螺虫乙酯烯醇、螺虫乙酯羟基、螺虫乙酯醇酮在番茄样品中的储藏稳定期至少为274 d,螺虫乙酯烯醇糖苷在番茄样品中储藏稳定期至少为182 d。     

烟蚜防治药剂筛选及其对异色瓢虫的安全性评价

采用喷雾法测定了5种烟草推荐使用药剂对烟蚜[Myzus persicae(Sulzer)]及其天敌异色瓢虫[Harmonia axyridis(Pallas)]3龄幼虫及成虫的毒性,并就各药剂对异色瓢虫的安全性进行了评价。结果表明,5%阿维菌素、3%啶虫脒、70%吡虫啉、1%苦参碱和50%吡蚜酮对烟蚜的LC_(50)分别是7.75、9.20、23.07、24.85和40.63 mg/L。对异色瓢虫3龄幼虫,3%啶虫脒的毒性最高LC_(50)为7.84 mg/L,其次为5%阿维菌素,50%吡蚜酮毒力最低LC_(50)为270.66 mg/L。对异色瓢虫成虫,3%啶虫脒的毒性最高LC_(50)为17.00 mg/L,其次为5%阿维菌素,50%吡蚜酮最低LC_(50)为541.33 mg/L。结合安全系数和益害比,1%苦参碱、50%吡蚜酮对烟蚜和异色瓢虫的选择性较高,适宜在田间与异色瓢虫组合应用防控烟蚜。     

6种杀虫剂在上海青中的残留消解动态及膳食风险评估

目的 评价蔬菜生产中6种常用杀虫剂5％啶虫脒乳油、15％哒螨灵水乳剂、20％溴氰虫酰胺可分散油悬浮剂、30％唑虫酰胺悬浮剂、22％氟啶虫胺腈悬浮剂和60 g/L乙基多杀菌素悬浮剂在十字花科蔬菜上海青中的残留消解动态,评估其膳食摄入风险.方法 于2018年4～10月在福州采用喷雾的施药方法进行了6种药剂在上海青上的残留试...     

麦蛾茧蜂对烟草粉螟的控制潜能研究

为明确麦蛾茧蜂对烟草粉螟的控制潜能,研究了麦蛾茧蜂对烟草粉螟幼虫的偏好性、功能反应、种内干扰和雄蜂存在对雌蜂的干扰效应。结果表明,麦蛾茧蜂偏好麻痹5龄幼虫,平均麻痹率74.00%±2.67%,对5龄幼虫的功能反应符合Ⅱ型,瞬时攻击率、处理时间、最大麻痹量分别为0.085/h、0.187 h和128.06头;麦蛾茧蜂种内干扰系数为0.316,该蜂对烟草粉螟幼虫的平均麻痹率（0.226~0.566）和搜寻效率（0.476~0.836）均随着雌蜂密度的增加而显著降低,但雄蜂的密度不影响雌蜂对烟草粉螟的麻痹量。研究证明,麦蛾茧蜂对烟草粉螟的控制潜力大,在烟仓烟草粉螟的绿色防控中具有良好的开发利用前景。     

烟粉虱MED隐种对不同烟草品种的适合度比较

烟粉虱MED隐种是近年来烟草上的重要害虫,为明确不同烟草品种对烟粉虱的抗性水平,应用微虫笼研究了烟粉虱在6个烟草品种上的寿命、产卵量、卵-成虫存活率、发育历期等重要生物学参数,比较了烟粉虱对不同烟草品种的适合度差异。结果表明：除卵孵化率外,烟粉虱MED隐种在供试烟草品种上的寿命、产卵量、卵-成虫存活率、发育历期均存在显著差异。雌成虫寿命和产卵量均以在翠碧1号上最高（35.9 d,236.5粒）,在NC89上最低（9.6 d,27.8粒）;雄成虫寿命在K326上最长（7.2 d）,在云烟87上最短（1.8 d）;卵-成虫存活率在红花大金元上最高（91.6%）,在云烟87上最低（81.4%）;发育历期在红花大金元上最短（19.5 d）,在云烟99上最长（21.1 d）。烟粉虱MED隐种对不同烟草品种的适合度高低顺序为翠碧1号、K326 > 红花大金元 > 云烟99、云烟87 > NC89。     

Microbiological quality of 18 degrees C ready-to-eat food products sold in Taiwan

A total of 164 samples of 18 °C ready-to-eat (RTE) food products, purchased in 1999–2000 from convenience stores and supermarkets in central Taiwan, were examined to determine the microbiological quality of these products. The 18 °C RTE food products, manufactured by 16 factories, were divided into groups based on the type of food and their major ingredients. Aerobic plate count, coliforms, Escherichia coli, Bacillus cereus, Staphylococcus aureus and psychrotrophic Pseudomonas spp. were evaluated. The incidence of E. coli and coliforms in these 18 °C RTE food products was 7.9% and 75.0%, respectively, while 49.8% and 17.9% of the samples were found to contain B. cereus and S. aureus, respectively. Among the samples tested, 1.3% of the food products contained more than 10⁵ CFU g⁻¹ of B. cereus and 0.7% contained more than 10⁵ CFU g⁻¹ of S. aureus. The pH values of the samples were all below 7.0, except for cold noodles, which had pH values ranging from 5.18 to 8.20. Among the five types of 18 °C food products tested, the highest incidence of E. coli (16%) and Pseudomonas spp. (64.0%) were detected in hand-rolled sushi in a cone shape. On the other hand, the highest incidence rate of coliforms, B. cereus, and S. aureus were found in sandwiches (88%), cold noodles (66.7%) and rice balls rolled in seaweed (25.0%), respectively. Food products made of ham contained the highest incidence of coliforms (88.0%) and E. coli (16.0%), while food products containing meat and ham as the major ingredients had the highest incidence rates of B. cereus (62.5%) and S. aureus (26.1%), respectively. For coliforms, E. coli, B. cereus and S. aureus, the percentage of 18 °C RTE food products exceeding the microbiological standards for RTE food accepted by Republic of China was 75.0%, 7.9%, 49.8% and 17.9%, respectively.     

Bioactivity of the essential oil extracted from Evodia rutaecarpa Hook f. et Thomas against the grain storage insects, Sitophilus zeamais Motsch. and Tribolium castaneum (Herbst)

The toxic, repellent and feeding deterrent activities of the essential oil extracted from Evodia rutaecarpa Hook f. et Thomas, were evaluated against Sitophilus zeamais adults and Tribolium castaneum larvae and adults. Contact toxicity assayed by topical application showed that S. zeamais adults were significantly more susceptible (LD₅₀=0.043 μg/mg body wt) to the essential oil than T. castaneum adults (LD₅₀=0.118 μg/mg body wt) and larvae (LD₅₀=0.093–0.126 μg/mg body wt). However, in the fumigation assays, S. zeamais (LC₅₀=41 μg/L air) was less susceptible to the essential oil than T. castaneum (LC₅₀=11.7 μg/L air). When compared with larvae of various ages, T. castaneum adults were more susceptible to the fumigant toxicity of the essential oil. Also, in the treated filter paper repellency test, the essential oil was more repellent to T. castaneum than to S. zeamais. A flour disk bioassay demonstrated that the essential oil of E. rutaecarpa had a weaker feeding deterrent action against T. castaneum adults than against T. castaneum larvae and S. zeamais adults. The reduction in growth rate of T. castaneum larvae and S. zeamais adults was mainly due to a behavioural (feeding deterrent) action rather than to post-ingestive toxicity of the oil.     

Antibacterial activity of extracts from some edible plants commonly consumed in Asia

Extracts of edible plants (26 species) from China, Japan, Thailand and Yemen were screened for their antibacterial activity against Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Escherichia coli and Salmonella infantis. Buffered methanol (80% methanol and 20% PBS) and acetone extracted inhibitory substances against tested bacteria from 16 plants, as revealed by the disc assay. The minimum inhibitory concentrations (MICs) of extracts determined by the agar dilution method ranged from 165 to 2640 mg l⁻¹. The most sensitive microorganism to extracts from Azadirachta indica, Cinnamomum cassia, Rumex nervosus, Ruta graveolens, Thymus serpyllum and Zingiber officinale was B. cereus, with MIC of 165 to 660 mg l⁻¹. E. coli and S. infantis were only inhibited by Cinnamomum cassia extracts at the highest MIC (2640 mg l⁻¹). L. monocytogenes (Tottori) was more resistant than the ATCC 7644 strain to extracts from Ruta chalepensis, Artemisia absinthium and Cissus spp. EDTA (0.85 mM) reduced the MICs of Cinnamomum cassia and Cissus rotundifolia by at least 50% when tested against E. coli, S. infantis, S. aureus and L. monocytogenes.     

Q型烟粉虱对9个烟草品种的趋性

Q型烟粉虱是近年来危害烟草的主要害虫之一,为明确我国烟区主栽烟草品种对Q型烟粉虱抗性水平的差异,实验室条件下,研究了其在9个不同烟草品种上的选择趋性、72 h产卵量、与叶片背面绒毛密度的相关性以及烟草叶片挥发物对其选择趋性的影响。结果表明,Q型烟粉虱成虫对烟草品种的选择性、产卵趋性在9个烟草品种间差异显著,烟草叶片背面绒毛密度与Q型烟粉虱产卵量具有显著相关性,其中NC71上的成虫数（8.22头/株）、产卵量（135粒/株）、叶背绒毛密度（164.67个/cm²）均最低。进一步利用Y嗅觉仪测定Q型烟粉虱对云烟97、中烟104、NC89、NC71烟草品种叶片气味及其提取物的行为反应,结果显示,NC71叶片及其提取物对Q型烟粉虱具有明显驱避作用（烟粉虱对其趋性分别为24.67%和13.33%）。NC71对Q型烟粉虱成虫选择性、产卵选择性抗性较强,具有在植烟区推广种植潜力。     

Microbiological detection of 10 quinolone antibiotic residues and its application to artificially contaminated poultry samples

To assess if microbiological inhibition tests for detection of antibiotic residues are suitable for routine screening for quinolone residues, the limit of detection (LOD) of 10 different quinolones and fluoroquinolones was determined. Two media were tested, one at pH 6 and the other at pH 8, each seeded with one of the following test strains: Bacillus subtilis, Escherichia coli or Bacillus cereus. LODs of the 10 substances were highest on plates seeded with B. cereus, intended for selective detection of tetracycline residues. The pattern of zones on the other four plates differed for the targeted quinolones: flumequine and oxolinic acid were detected at lower concentrations at pH 6, while the LODs of ciprofloxacin, enrofloxacin, danofloxacin, marbofloxacin, sarafloxacin and norfloxacin were lower at pH 8. Nine of the 10 quinolones were detected more easily with E. coli, but the LOD of difloxacin was lower with B. subtilis. Finally, the three most sensitive media were selected and fluid from chicken meat, spiked with eight quinolones near maximum residue limits (MRL), analysed on each plate. The plate seeded with E. coli at pH 8 detected five of eight quinolones at levels of interest, but an additional E. coli plate at pH 6 was necessary for detection of flumequine in species other than poultry and fish. None of the plates detected oxolinic acid and difloxacin at MRLs in muscle tissue.     

The efficacy of linalool, a major component of freshly-milled Ocimum canum Sims (Lamiaceae), for protection against postharvest damage by certain stored product Coleoptera

Linalool was present at 8.6 ± 0.9 mg/g in the dried leaves of Ocimum canum Sims, an annual mint used in Rwanda to protect against postharvest insect damage. Direct exposure of adults of Zabrotes subfasciatus (Bohem.) to milled, dried O. canum leaves resulted in 100% mortality of males and 50% mortality of females after 48 hr. Dose-response curves for linalool were completed with adult Z. subfasciatus, Acanthoscelides obtectus (Say), Rhyzopertha dominica (F.), and Sitophilus oryzae (L.) using a filter paper bioassay. The LC₅₀ values were: 428 μg/cm² for Z. subfasciatus; 405 μg/cm² for A. obtectus; 428 μg/cm² for R. dominica; 427 μg/cm² for S. oryzae. Knockdown was occasionally followed by recovery at doses less than the LC₅₀ for all species. There are significant differences in the LC₅₀ and LT₅₀ values for male and female Z. subfasciatus. At the lower dosages hyperactivity rarely preceded moribundity and mortality where these occurred, while at higher dosages hyperactivity occurred soon after initial exposure and preceded imminent death. A concentration increase from 250 to 750 μg/cm², representing a tripling of dosage, spanned th 10–100% response mortality for all species at 24 hr. Air-exposure of linalool-treated papers (500 μg/cm²) for up to 24 hr significantly decreased toxicity to both sexes of Z. subfasciatus. Quantitative analysis showed the only significant decrease in the amount of linalool to occur after 0.25 hr, and this did not fully correlate with the resulting decrease in efficacy against both sexes of Z. subfasciatus. The results are discussed in terms of the efficacy of using O. canum for the protection against loss due to insects in the traditional food storage systems of Rwanda.