羧基化多壁碳纳米管分散固相萃取-三重四极杆气质联用法测定茶叶中16种农药残留量

基于羧基化多壁碳纳米管（MWCNTs-COOH）分散固相萃取净化，结合三重四极杆气质联用仪，建立了茶叶中16种农药残留量的快速分析检测方法。茶叶经乙酸乙酯提取，以羧基化多壁碳纳米管和乙二胺-N-丙基硅烷化硅胶（PSA）吸附提取液中的杂质，离心过滤后经三重四极杆气质联用仪测定，基质匹配外标法定量。结果表明，目标物质在各自线性范围内的线性关系良好，相关系数（r）均大于0.99。空白茶叶样品平均加标回收率在71.2%～128.2%之间，相对标准偏差（n=6）为2.3%～9.2%；方法的定量限为0.5～10.0μg/kg。建立的方法在回收率、检测限、准确度和灵敏度等方面均能满足农药残留分析的要求，适合于茶叶中相关农药残留的快速检测。     

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。     

分散固相萃取-反相高效液相色谱法测定蔬菜、水果中10种氨基甲酸酯类农药残留

建立分散固相萃取-反相高效液相色谱同时测定蔬菜和水果中10种氨基甲酸酯类农药(涕灭威，涕灭威砜，涕灭威亚砜，克百威，3-羟基克百威，灭多威，甲萘威，异丙威，速灭威，仲丁威)残留的分析方法。样品经乙腈提取，PSA分散固相萃取净化，液相色谱柱后衍生分离，荧光检测(λex＝330 nm, λem＝465 nm)测定，外标法定量。10种农药在0.005～0.50 mg/L范围内线性关系良好；检出限在0.004～0.008 mg/L；平均加标回收率在75.6%～112.3%，相对标准偏差(RSD)在 0.8%～10.2%。该方法具有快速、灵敏、准确、重现性好以及操作简单等特点，适合日常大批量蔬菜和水果样品中10种氨基甲酸酯类农药残留的测定。     

香蕉中噻唑膦残留分析方法研究

建立香蕉中噻唑膦的超高效液相色谱串联质谱法(UPLC-MS/MS)残留测定方法。香蕉样品采用乙腈提取和PSA+C18分散固相萃取,采用UPLC-MS/MS多反应模式(MRM)进行分析测定。噻唑膦在添加水平0.01~1.0 mg/kg范围内,平均回收率为94.3%~107.5%,相对标准偏差为7.9%~11.0%。采用外标法定量,方法的检出限为0.001μg/m L,定量限为0.005 mg/kg。该方法简单、准确、重复性较好且节省溶剂,适用于香蕉中噻唑膦的残留检测。     

酶联免疫法测定土壤中莠去津

用定量酶联免疫法对土壤中莠去津的残留进行初筛,然后对阳性样品用气相色谱-质谱法进行确证,并对两种方法的回收率、精密度及检测限进行评价.向土壤样品中分别添加0.3、1.0、3.0μg/kg浓度水平的莠去津标准品时,ELISA的平均回收率为92.20%～97.14%,变异系数为1.69%～4.11%,检测限为0.04μg/kg;GC-MS的平均回收率为85.46%～87.68%,变异系数为2.93%～4.05%.检测限为0.03μg/kg.对酶联免疫试荆盒筛选的3个阳性样品用GC-MS进行确证,测定结果基本一致,结果满意.研究表明酶联免疫法重复性好、准确度较高,是一种土壤中莠去津残留的快速筛选方法.     

超高效液相色谱-串联质谱法测定茶叶中灭草松及其代谢产物残留量

建立了超高效液相色谱-串联质谱法测定茶叶中灭草松及其代谢产物的快速检测方法。茶叶样品使用0.1%冰乙酸-甲醇混合溶液提取，上清液使用石墨化碳黑(GCB)、N-丙基乙二胺(PSA)、Mg SO₄组成的复合填料净化过滤后，经超高效液相色谱-串联质谱法测定，最后通过外标法定量。结果表明，在试验条件下，灭草松在0.001～0.010 mg/L含量范围内具有较好的线性关系，其代谢产物在0.000 2～0.002 0 mg/L含量范围内同样具有较好的线性关系，相关系数(R²)均大于0.995；本方法对灭草松的定量限为0.01 mg/kg，对两种代谢产物的定量限均为0.002 mg/kg。该方法操作简单、快捷、灵敏、精密度高、成本低，能够满足茶叶中灭草松及代谢物的检测需求。     

超声辅助-漂浮固化分散液液微萃取-气相色谱法测定茶叶中5种拟除虫菊酯类农药残留

建立了超声辅助-漂浮固化分散液液微萃取(UA-DLLME-SFO)-气相色谱法(GC)测定茶叶中甲氰菊酯、氟氯氰菊酯、氯氟氰菊酯、氰戊菊酯、溴氰菊酯5种拟除虫菊酯类农药残留的方法。获得最佳试验条件为20μL十六烷(萃取剂)和800μL丙酮(分散剂),质量分数为4%的氯化钠,水相pH为4,35℃超声30 min,-3℃、10 000 r·min~(-1)离心5 min后,去除水相后经气相色谱测定。结果表明:在1~150μg·kg~(-1)范围内,5种拟除虫菊酯类农药呈良好的线性关系,相关系数均大于0.9994,在1~5μg·kg~(-1)添加水平下,平均回收率为92.3%~99.6%,日内相对标准偏差(RSD)均低于3.5%(n=6),日间相对标准偏差(RSD)均低于5.9%(n=3),5种农药在茶叶中的检出限为0.11~0.24μg·kg~(-1),定量限为0.36~0.81μg·kg~(-1)。该方法操作简便、快速、安全、成本低、重现性好,适用于茶叶样品中拟除虫菊酯类农药残留的分析。     

全自动固相萃取结合UPLC-MS/MS测定茶叶中的草甘膦及其代谢物

建立超高效液相色谱-质谱/质谱法(UPLC-MS/MS)测定茶叶中草甘膦及其代谢物氨甲基膦酸的分析方法。用水-二氯甲烷体系对样品进行提取和初步除杂，在全自动固相萃取仪中通过聚苯乙烯键合苯磺酸混合型阳离子交换柱进一步净化样品溶液基质，利用正交试验和方差分析得出最优的衍生条件为5%硼酸钠缓冲溶液和10 mg·m L^-1的9-芴基甲基三氯甲烷(FMOC-Cl)衍生剂在室温下衍生2 h，衍生后的样品溶液在HSS T₃色谱柱和5 mmol·L^-1乙酸铵溶液(含0.1%甲酸)-乙腈流动相体系下进行梯度洗脱分离，经UPLC-MS/MS进行内标法定量分析。草甘膦和氨甲基膦酸在0.2～50 ng·m L^-1质量浓度范围内线性关系良好，相关系数(R²)均大于0.999，该方法的检出限为2μg·kg^-1，定量限为5μg·kg^-1。低、中、高3个加标水平(5、50μg·kg^-1和250μg·kg^-1)的回收率为94...     

微型DPSA-1仪-SPCE微分电位溶出法同步快速检测茶叶中的铅、镉、铜

用微型DPSA-1仪结合丝网印刷碳电极(SPCE),以微分电位溶出法对茶叶中的铅、镉、铜进行同步快速检测。优化的试验参数如下:Hg2+浓度为3×10-4 mol/L,支持电解质为1.5 mol/L pH4.0的氯化铵溶液,富集电位-1.1 V,终止电位-0.2 V,富集时间200 s。在此条件下获得的检测结果在20～840μg/L(相当于茶叶中铅含量为1～42 mg/kg)范围内呈现良好的线性关系,铅的相关系数为r=0.99749,检出限为1.12μg/L(S/N=3);镉的相关系数为r=0.99740,检出限为1.09μg/L(S/N=3);铜的相关系数为r=0.99612,检出限为1.23μg/L(S/N=3)。研究了检测过程中存在多种干扰离子对于铅、镉、铜检测的干扰情况。试验所得检测结果与国标检测法进行t检验,无显著差异。比较常规的检测技术,微型DPSA-1型仪结合SPCE微分电位溶出法同步检测茶叶中的铅、镉、铜,是更加经济的一种快速检测方法,可实现样品的高比例筛检,还可推广应用于其他类型食品和环境样品中铅、镉、铜的同步快速检测。     

QuEChERS-超高效液相色谱-三重四极杆质谱法检测茶叶中250种农药残留

建立了QuEChERS-超高效液相色谱-串联质谱法测定茶叶中250种农药残留及代谢物的分析方法。前处理采用QuEChERS方法，样品用含有1%乙酸-乙腈振荡提取，经十八烷基硅胶(C₁₈)、N-丙基乙二胺(PSA)、石墨化碳黑(GCB)和无水硫酸镁混合型净化剂固相分散萃取净化。采用2 mmol/L甲酸铵+0.01%甲酸水溶液-2 mmol/L甲酸铵+0.01%甲酸甲醇溶液作为流动相，以0.3 m L/min的流速进行梯度洗脱，采用ACQUITY HSS T3色谱柱(2.1 mm×100 mm,1.8μm)分离，在ESI正离子模式下，采用动态反应监测S-MRM (Scheduled-MRM)模式进行扫描，外标法定量。结果表明，250种农药在各自质量浓度范围内均呈现良好线性关系，相关系数>0.994，定量限为0.01 mg/kg，在3个添加水平(0.01、0.02、0.05 mg/kg)下回收率在71.3%～107.1%之间，相对标准偏差小于10%。由此可得，该新方法快速、灵敏、准确，适用于茶叶中农药残留检测。     

Seasonal changes in properties of abandoned terraced paddy field soil incubated under different water content conditions

The chemical properties of soil samples collected in August and November from an abandoned terraced paddy field dominated by reeds were examined by in vitro incubation under normal moisture and flooded conditions. Soil pH extracted with water [pH(H₂O)] was higher in soil samples collected from a depth of 0–10 cm in November than in samples collected in August; a high pH(H₂O) was maintained even during nitrification under normal moisture conditions. When soil samples collected in August from a depth of 0–10 cm were incubated under flooded conditions, a significant decrease in reduction potentials (Eh) and an increase in total Fe²⁺ concentrations were observed. Reductive conditions during sampling were strong in soil samples collected in August from a depth of 40–50 cm. Moreover, under normal moisture conditions, soil samples collected in August showed significant decreases in pH(H₂O) and significant production of water-soluble SO₄ ^2? than those collected in November. Glucose addition to soil samples collected from a depth of 0–10 cm caused nitrogen immobilization under normal moisture conditions, increases in exchangeable Fe²⁺ and Mn²⁺, and decreases in exchangeable bases (Ca²⁺, Mg²⁺, K⁺, and Na⁺) under flooded conditions. Seasonal changes in soil properties were probably due to microbial activity and vegetation phenology; thus, the timing of soil sampling influenced incubation experiment results. When abandoned terraced paddy fields are created as biotopes, seasonal changes in reductive soil conditions and slope position must be considered to prevent soil acidification and base cation elution.     

二化螟实时荧光定量PCR内参基因筛选和表达稳定性评价

【目的】筛选特定试验条件下二化螟(Chilosuppressalis)稳定表达的内参基因,为二化螟基因表达研究奠定基础。【方法】根据二化螟转录组测序结果挑选出11个候选基因,利用实时荧光定量PCR测定其在二化螟不同发育历期、不同组织、温度处理、杀虫剂处理、取食不同饲料、取食不同水稻、dsRNA处理和混合样品的表达量,利用RefFinder、BestKeeper、Ge Norm和NormFinder等软件和ΔC_t值对11个候选基因的稳定性进行评估。【结果】5种分析方法表明,在二化螟不同发育历期稳定性较高的内参基因是AK、RPL10和EF1,不同组织中稳定性较高的内参基因是EF1、TUB和ACTB,不同温度下较稳定的内参基因为TUB、RPL10和EF1,杀虫剂处理样品中较稳定的是TF4和ACTA,取食不同饲料较稳定的是TUB、TF4、EF1和RPL10,取食不同品种水稻较稳定的是TUB和EF1,dsRNA处理样品中较稳定的是TUB、AK、ACTB和EF1,混合样品中较稳定的是EF1、TUB和ACTB。【结论】为不同试验条件下选择合适的内参基因提供了参考,也有利于在二化螟基因表达研究中获得更加可靠准确的数据。     

栗香绿茶香气萃取方法优化及其芳香成分分析

以14个具典型栗香特征和2个甜香特征的绿茶茶样为研究对象,比较了固相微萃取头种类、萃取温度、萃取时间及电解质浓度对栗香香气物质种类和总量的影响,探索萃取栗香绿茶香气物质的适宜条件,并开展栗香绿茶的特征峰分析。结果表明,采用DVB/CAR/PDMS固相微萃取头,在50℃下吸附50βmin,电解质浓度控制为1~3βmg·mL^-1时,能达到最佳的吸附效果;在该条件下,共检测出171种挥发性化合物,筛选出30个峰为栗香绿茶的共有特征峰,其中醇类5种、烯烃类4种,烷烃类7种,且各色谱峰相对峰面积的RSD≤5.0%,显示其具有较好的重复性。通过夹角余弦法和相关系数法进行相似度分析,证实栗香特征峰具有较好的解释能力。     

Susceptibility to Coolness at the Young Microspore Stage under High Nitrogen Supply in Rice (Oryza Sativa L.). Proteome Analysis of Mature Anthers

Abstract

In vitro pollen germination experiment using agar plates showed that the growth under high nitrogen conditions enhanced the damage to pollen germination ability caused by the cooling at the young microspore stage. To clarify the physiological factors related to this damage to pollen germination, we performed the comparative proteome analysis of mature anthers and identified proteins that were changed by high nitrogen conditions or high nitrogen plus cooling conditions. Proteins were extracted from mature anther samples and separated by two-dimensional polyacrylamide gel electrophoresis. By comparing anther protein maps of the samples collected from the plants grown under standard nitrogen conditions, high nitrogen conditions and high nitrogen plus cooling conditions, we found 11 protein spots, which varied with the treatment. These protein spots were identified based on the rice proteome database and/or peptide mass fingerprinting (PMF) analysis after digestion with trypsin. Digested samples were analyzed by matrix-assisted laser desorption/ionization-time flight mass spectrometry to produce PMF data. Database searches using these PMF data revealed the identities of 9 proteins. Seven of these proteins were polypeptides involved in cell elongation, stress responses and sugar metabolism. The relation between the fluctuations of these proteins and the decrease in pollen germination are discussed.     

The use of irradiation for the preservation of fresh herbage for subsequent botanical and chemical analysis

The use of irradiation as a means of preserving fresh forage for subsequent botanical and chemical analysis was examined as a possible alternative to preservation by freezing. Forage samples containing a mixture of grass species were given irradiation doses of either 2-5 Mrad (25 k Grays) or 5-0 Mrad (50 k Grays). These samples were then stored in the dark under either ambient or chill (+ 2°C) conditions for up to 5 months, while similar samples of fresh forage were stored over the same period deep frozen at — 15°C. No spoilage or signs of any subsequent senescence were observed in the forage given the 5-0 Mrad irradiation treatment during the 5 month storage period. In the 2-5 Mrad treated material some browning of lamina tips occurred. However, the irradiation treatment did cause some colour changes, mainly a darkening of the green tissue. The state of preservation was also assessed by measuring the rate at which stored herbage could be separated into the constituent species. No difference in separation rates was found between samples that had either been stored frozen or irradiated at 5-0 Mrad (and then stored under either ambient or chill conditions); however, separation rates were slower on the 2-5 Mrad treated samples. The irradiation treatment did not cause any significant change in percent nitrogen content. However, water-soluble carbohydrate contents in the irradiated samples were significantly lower. The cost of commercial irradiation treatment was less than 20% of the commercial cost of freezing and cold storage.     

New insight into compressive shrinkage finishing in a garment company: The effects on physical,mechanical and colorimetric properties of cotton woven fabrics

Compressive shrinkage or compressive shrinkage finishing is one of the most important finishing procedures in the textile industry to improve the dimensional stability of cotton fabrics. Study of the physical and mechanical properties of compressive shrinkage finished fabrics could be useful for optimizing the treatment conditions. This research was carried out in a production line of a recognized garment company on cotton woven fabrics with two different woven patterns (twill and plain). The samples were first dyed with reactive and sulfur dyes in a jigger dyeing machine and finished with a silicone softener. The dried fabrics were then processed in a compressive shrinkage machine. Several physical and mechanical properties of the samples were evaluated including area shrinkage, crimp percentage, thickness, abrasion resistance, drapeability, mechanical and colorimetric properties. The results showed that the thickness of all treated samples increased due to compressive shrinkage. The fabrics were analyzed with a Martindale Abrasion Tester to determine the abrasion resistance. Interestingly, we noted an increase in the abrasion resistance. After the compressive shrinkage process, the strength of the plain woven fabrics decreased in the warp direction, but increased for twill woven cotton fabrics. On the contrary, the strength of all samples increased in the weft direction. Colorimetric evaluation of the samples showed that the effect of compressive shrinkage on the color of all samples was negligible.     

文心兰品种变异RAPD分子检测技术的建立及应用

通过对DNA提取方法的改良,随机引物的选择、RAPD反应条件的筛选,建立文心兰品种变异RAPD分子标记检测技术。利用该技术对3个母本园品种和1个试管苗品种进行RAPD检测,结果是品种“黄金2号”和“黄金3号”未发现变异;7个引物对品种“新奇士”共扩增出63条清晰带,3个样品带型发生变化,样品变异率为10%;14个引物对“黄金2号”试管苗共扩增出119条清晰带,9个样品带型发生变化,样品变异率为9.4%。结果表明,该技术能有效用于文心兰品种的变异检测。     

Chemical Characterization of Atlantic Cod (Gadus morhua) Collagen Hydrolyzed Using Enzyme Preparation Derived from Red King Crab (Paralithodes camtschaticus) and Its Potential as a Core Component of Bacterial Culture Medium

The Atlantic cod (Gadus morhua) and red king crab (Paralithodes camtschaticus) processing wastes are massive and unutilized in the Murmansk region of Russia. The samples of skin-containing waste of Atlantic cod fillets production were hydrolyzed using enzyme preparations derived from red king crab hepatopancreases, porcine pancreases, and Bacillus subtilis bacteria. The activity of enzymes from crab hepatopancreases was significantly higher than the activity of enzymes derived from other sources. The optimal conditions of the hydrolysis process have been figured out. The samples of cod processing waste hydrolysate were analyzed for amino acid composition and molecular weight distribution. The samples of hydrolysate were used as core components for bacterial culture medium samples. The efficiency of the medium samples was tested for Escherichia coli growth rate; the most efficient sample had an efficiency of 95.3% of that of a commercially available medium based on fish meal. Substitution of medium components with those derived from industrial by-products is one of the ways to decrease a cost of a culture medium in biopharmaceutical drug production.     

测土配方施肥专家系统应用模式概况

测土配方施肥技术模式是通过测土配方施肥技术的宣传和培训、土壤样品采集、样品检测、数据整理与分析、专家制定施肥模型等步骤,最后应用专家系统--优雅施触屏一体机进行数据处理,打印出配方施肥建议卡。该模式的推广应用增加了测土配方施肥的科技含量,提高了工作效率,对增产、节支、增收起到了很大的作用。     

Measurement of black spot susceptibility of potatoes

The black spot reaction was initiated by dropping plugs of varying weights from different heights onto the stem end of potatoes with known temperatures. The degree of discoloration was assessed in a scale from 0 to 5, the results were added and the sum was divided by the number of tubers. Relationships between black spot incidence, temperature and impact were very close in samples containing 100 or more tubers. This was not always the case, however, if samples were of a more manageable size of 20 to 25 tubers. Results indicated the desirability of testing under a standard set of conditions—such as 100 g falling 30 cm onto the stem end of tubers with a temperature of 10 C. The results of visual assessment of the black spots were closely related to the results of a more objective, but also more laborious, method in which the amount of discolored tissue was weighed.