水浴热浸提—原子荧光光谱法测定植物干样中的汞

[目的]研究沸水浴浸提—原子荧光光谱法测定植物干样中汞的方法。[方法]试验采用1︰1王水(盐酸︰硝酸=3︰1)沸水浴消解样品,AFS-930原子荧光光度计测定样品中汞的含量。[结果]结果显示:该方法回收率在94.7%~111.4%,相对标准偏差在2.3%~4.9%。[结论]试验证实该方法具有简便、快速、灵敏度高等优点,为植物干样中痕量汞的检测提供了快速有效的分析方法,其所用仪器简单,操作简洁,耗时短,值得推广。     

王水水浴消解-双道原子荧光光谱法（AFS）同时测定土壤中的汞和硒

建立王水水浴消解一双道原子荧光光谱法同时测定土壤中的汞和硒的方法,优化王水水浴消解和AFS测定条件。该法的汞检出限为0．002μg／L,硒的检出限为O．100wgL;汞的相对标准偏差为0．0020％～0．0340％,硒的相对标准偏差为0．0018％～0．0580％;汞的加标回收率为95．6％-101-4％,硒的加标回收率为96.4％～103．0％。该法操作快速、简便,结果准确、可靠,适用于大批量土壤样品中汞和硒的同时测定。     

Use of Iodized Versus Non-iodized Sodium Chloride in Therapeutic Dips and Baths for Freshwater Fish

Salt (NaCl) is a common therapeutant in fish culture. The use of salt containing iodine may be harmful to fish. The goal of this study was to determine if using iodized saltfor dips and baths increases morbidity/mortality of fish and establishes the LC₅₀ of iodine for three commercially important species: koi, Cyprinus carpi; guppy, Poecilia reticulata; and Jack Dempsey, Rocio octofasciata. Fish were exposedto a salt bath (4 g/L) or a salt dip (25 g/L) using either iodized or non-iodized salt and observed for clinical signs of iodine toxicity or death. For the LC₅₀ trials, one fish of each species was exposed to a range of iodine concentrations for a period of 24 h. There were no significant differences in mortality between fish treated with iodized vs. non-iodized salt. The use of iodized salt for baths and dips appears to be safe in the three species tested. LC₅₀ of iodine in these species appears to be greater than 1.4 mg/L.     

不同消解方法测定土壤有机质含量

重铬酸钾为氧化剂,选用油浴、磷酸浴、电沙浴、微波消解加热消解土壤有机质,比较有机质测得量。结果表明：微波法有机碳氧化率最高,精密度和准确度最高,平行测定RSD为0．42％～0．69％。磷酸浴法氧化率高,准确度与精密度高,平行测定RSD为0．43％～0．70％。磷酸浴法温度稳定,易于控制,简单,安全,环保。微波法和磷酸浴法试验结果相对误差为＋0．61％～＋1．39％,可以作为实验室分析土壤有机质的标准加热消解方法。油浴法与沙浴法氧化率较低,试验误差大。油浴法温度不易控制,存在环境污染。     

热淋清颗粒含药血浆的高效液相色谱分析

[目的]对热淋清颗粒的含药血浆进行分析,为筛选确定热淋清颗粒的药效成分奠定基础。[方法]在建立热淋清颗粒高效液相色谱指纹图谱的基础上,通过比较热淋清颗粒甲醇提取物、热淋清颗粒含药血浆和空白血浆的高效液相色谱指纹图谱,确定热淋清颗粒血中移行成分。[结果]在热淋清颗粒含药血浆中发现了6个入血成分,其中3个为原型成分,其余几个可能为代谢产物。[结论]6个入血成分可能成为热淋清颗粒的体内直接作用物质,对其进行深入研究,将有助于探索热淋清颗粒的药效物质基础。     

灰叶胡杨花粉中总黄酮提取方法的研究

[目的]比较不同提取方法对灰叶胡杨花粉中总黄酮含量的影响。[方法]采用水浴法、超声提取法、微波提取法和超声-微波协同萃取法提取黄酮,以芦丁为对照品,用分光光度法测定总黄酮的含量。[结果]水浴提取法、超声提取法、微波提取法和超声-微波萃取法提取的总黄酮含量分别为1．747％、1．576％、2．053％和2．176％;提取效果为：超声-微波协同萃取法〉微波提取法〉水浴提取法〉超声波提取法。[结论]超声-微波协同萃取法是提取灰叶胡杨花粉总黄酮较优的方法。     

An experimental means of transmitting pancreas disease in Atlantic salmon Salmo salar L. fry in freshwater

A challenge model for pancreas disease in Atlantic salmon, Salmo salar L. fry, was developed comparing two salmonid alphavirus (SAV) subtypes: SAV1 and SAV5. Viral doses of 3 × 10⁵ TCID₅₀ mL⁻¹ for SAV1 and 3 × 10⁴ for SAV5 were tested in triplicate tanks, each containing 450 salmon fry. Cumulative mortalities of 1.2% were recorded. Titres of virus recovered from the mortalities ranged from 10² to 10⁷ TCID₅₀ mL⁻¹. Fry were sampled at 3, 5 and 7.5 weeks post-challenge. Sampling after 3 weeks revealed a high prevalence of infection in the absence of clinical signs, and infectious virus was recovered from 80% and 43% of sampled fry infected with SAV1 and SAV5, respectively. After 5 weeks pancreas, heart and red skeletal muscle lesions were generally observed, whilst degeneration in white skeletal muscle was observed only in fish infected with SAV1. In situ hybridisation confirmed the presence of viral genome in infected pancreas, heart and muscle. After 7.5 weeks, infectious virus (both isolates) was recovered from 13.3% of the fish sampled, with a viral titre of 10² TCID₅₀ mL⁻¹. Clearly, salmon fry are susceptible to SAV infection and pancreas disease.     

木奶果果皮多酚提取工艺优化及其体外抗氧化活性研究

研究木奶果果皮多酚水浴振荡辅助提取工艺及其体外抗氧化活性。在单因素试验基础上,采用响应面法优化木奶果果皮多酚的水浴振荡辅助乙醇提取工艺,并以V_C为对照,对DPPH自由基、ABTS自由基和超氧阴离子自由基清除能力进行探讨。结果表明:采用优化后的工艺条件,提取时间63 min、提取温度65℃、乙醇浓度66%、液料比42∶1(m L/g),木奶果果皮多酚提取量为31.2 mg/g,与模型预测值31.0 mg/g相近,最佳工艺实用性强。体外抗氧化活性实验表明,木奶果果皮多酚对于DPPH自由基、ABTS自由基和超氧阴离子自由基的IC50值分别为12.3、2.35、0.141 mg/m L,最高清除率分别为90.6%、99.1%和61.9%,说明木奶果果皮多酚具有很强的抗氧化活性。     

热激后冰浴时间与复苏时间对化学转化法转化效率的影响

[目的]研究化学转化过程中热激后冰浴时间和复苏时间对转化效率的影响,确定简便快速的转化方法。[方法]采用2种缓冲溶液制备感受态,以热激后冰浴时间或复苏时间为变量,研究这2个因素与转化效率的关系。[结果]冰浴2min,复苏30或40min达到最佳转化效率;冰浴和复苏时间为0时仍能获得相当数量的转化子。[结论]热激后冰浴和复苏时间对转化效率有一定影响,但不是决定性因素。因此,在一般性转化试验中可以省略这2个步骤以节省时间。