多波长高效液相色谱法测定米豆腐中4种色素

目的建立多波长高效液相色谱法监测米豆腐中添加柠檬黄、胭脂红、日落黄、亮蓝等4种人工色素。方法氨碱性条件下用水作溶剂超声提取米豆腐中色素,提取液用柠檬酸溶液调节p H值至弱酸性,高效液相色谱在线分离。经Waters C_(18)色谱柱(250 mm×4.6 mm,5μm)分离;以0.02 mol/L乙酸铵(p H值5.5)—甲醇为流动相进行梯度洗脱,流速为1.0 m L/min,柱温30℃,以各组分的最大吸收波长为检测波长,外标法定量。结果 4种组分在1.00~100μg/m L范围内线性关系良好,相关系数在0.9993~0.9997(n=7),平均加标回收率在87.4%~89.5%(n=3)。结论该斱法同时测定米豆腐中4种人工色素,前处理简单、快速,定量准确,灵敏度高,可用于米豆腐的质量控制。     

液相色谱-串联质谱法同时测定中草药保健食品中15种有机磷和氨基甲酸酯类农药残留

目的建立高效液相色谱-串联质谱法同时测定中草药保健食品中15种有机磷和氨基甲酸酯类农药残留。方法样品经乙腈提取后,高速离心,经分散型固相萃取小柱净化。采用Atlantis C_(18)(2.1 mm×100 mm,3μm)柱,以0.1%甲酸-乙腈为流动相,梯度洗脱分离。质谱采用正离子模式(electrospray ionization,ESI+),多反应监测模式(multiple reaction monitoring,MRM)进行检测,基质曲线外标法定量。结果该方法对15种农药残留的线性范围为0.001~0.1μg/mL,线性相关系数r≥0.993,加标回收率为82.7%~113.3%,相对标准偏差为2.7%~10.6%,检出限为0.8~24.6μg/kg。结论本方法操作简单、快捷,适用于中草药保健食品中15种有机磷和氨基甲酸酯类农药残留的同时检测,为保健食品质量控制提供依据。     

FIA-IC法同时测定水中痕量I-、SCN-、ClO-4及草甘膦

采用活性碳纤维作吸附剂流动注射在线富集,并采用流动注射(FIA)―离子色谱(IC)联用技术对吸附柱中富集的I~-、SCN~-、ClO_4~-和草甘膦进行定量测定。结果表明,I~-、SCN~-、ClO_4~-和草甘膦的检出限为0.08~0.14mg/L,线性范围为0.01~5.00 mg/L,相关系数分别为0.997 9,0.999 0,0.998 7,0.998 1,加标回收率为94.9%~99.2%。     

富GIF啤酒酵母制品对糖尿病大鼠空腹血糖和糖耐受量的影响

目的研究富GTF啤酒酵母制品对糖尿病大鼠空腹血糖和糖耐受量的影响。方法采用腹腔注射四氧嘧啶建立糖尿病大鼠模型,将模型大鼠随机分为3组,分别每天服用普通面包酵母0.1g、富GTF啤酒酵母干粉0.1g和富GTF啤酒酵母胶囊1粒,每天测空腹血糖。30d后进行糖耐受量试验,测0、0.5和2h各时间点血糖。结果富GTF啤酒酵母胶囊和富GTF啤酒酵母干粉不降低正常大鼠血糖。服药30d后,富GTF啤酒酵母胶囊组糖尿病大鼠空腹血糖下降52.45%,富GTF啤酒酵母干粉组血糖下降32.34%,而面包酵母干粉无降糖作用。各样品组糖耐受量2h后均下降,富GTF啤酒酵母胶囊组血糖下降迅速。结论富GTF啤酒酵母胶囊降血糖效果显著,优于富GTF啤酒酵母干粉,并能显著改善糖尿病大鼠糖耐受量。     

Retail electricity price savings from compliance flexibility in GHG standards for stationary sources

The EPA will issue rules regulating greenhouse gas (GHG) emissions from existing steam boilers and refineries in 2012. A crucial issue affecting the scope and cost of emissions reductions will be the potential introduction of flexibility in compliance, including averaging across groups of facilities. This research investigates the role of compliance flexibility for the most important of these source categories—existing coal-fired power plants—that currently account for one-third of national emissions of carbon dioxide, the most important greenhouse gas. We find a flexible standard, calibrated to achieve the same emissions reductions as a traditional(inflexible) approach, reduces the increase in electricity price by 60 percent and overall costs by two-thirds in 2020. The flexible standard also leads to substantially more investment to improve the operating efficiency of existing facilities, whereas the traditional standard leads to substantially greater retirement of existing facilities.     

Suppressing the non-switching contribution in BiFeO3-Bi4Ti3O12 based thin film composites to produce room-temperature multiferroic behavior

Exploiting the exceptional multiferroic characteristics of BiFeO₃-based systems depends largely on controlling the high leakage currents that often constrain the ferroelectric response of this material. This limiting circumstance is even more restrictive in the film geometry, where the high area/volume ratio can add complications related to the uncontrolled loss of a particularly volatile element such as bismuth. In this work we address the suppression of such non-switching contribution by preparing BFO-BiT thin film composites and using a low-temperature processing protocol in a fully aqueous medium. With an adequate and systematic doping of both oxides, the produced composites show both magnetic and ferroelectric response at room temperature, in a process that is also related to the fine matching between the two crystal lattices involved. The results obtained further indicate the possibility of applying a simple, sustainable protocol with high scalability prospects to fabricate exploitable multiferroic systems, i.e. with no need for large energy inputs nor sophisticated equipment.     

酵米面和银耳及其制品中毒黄素和热诚菌素的检测方法的建立及稳定性比较

建立了测定酵米面和银耳及其制品中的毒黄素和热诚菌素的高效液相色谱法。样品经提取后,以C18色谱柱分离目标化合物,保留时间和光谱图定性,外标法定量。对建立的方法与现有的方法进行了对比,同时比较了两种目标物在不同条件下的稳定性。结果表明：两种目标物在0.20~20.00 mg/L浓度范围内呈良好线性,R2>0.999,检出限分别均为0.15 mg/kg（酵米面）和0.30 mg/kg（银耳及其制品）,方法回收率为79.77%~104.36%,相对标准偏差（RSD）为0.96%~8.91%（n=6）。毒黄素和热诚菌素在碱性条件下含量均迅速降解至40%以下,毒黄素在酸性条件下会在5个月内降解至26%以下,而热诚菌素在酸性条件下以及两者在甲醇溶液中5个月内稳定性较好,吸光值RSD均小于3.18%。该方法较现有的方法简便快捷、干扰小、准确度高,可应用于酵米面和银耳及其制品中的毒黄素和热诚菌素的检测。稳定性试验可为后期的解毒或避毒提供有力的参考。     

气相色谱-质谱联用与相对气味活度值法分析坛子肉风味物质的研究

目的 分析探讨坛子肉中的关键性风味物质。方法 应用固相微萃取-气相色谱-质谱法(solid phase microextraction-gas chromatography-mass spectrometry, SPME-GC-MS)对5种不同坛子肉的挥发性风味物质进行分离鉴定, 并应用相对气味活度值法(relative odor activity value, ROAV)对5种坛子肉共有的挥发性风味物质进行特征性分析。结果 5种不同坛子肉中分别检测出60、57、51、54、57种挥发性风味物质, 坛子肉主要风味物质有醛、醇、酯、酸、酮等物质, 其关键挥发性风味物质为己醛、乙酸乙酯、反式-2-壬烯醛、1-辛烯-3-醇、壬醛、3-甲基丁醛和2-己烯醛。结论 本研究方法可以得出坛子肉的主要及关键挥发性风味物质, 方法有一定的实用性。     

Authentication of Polygonati Odorati Rhizoma and other two Chinese Materia Medica of the Liliaceae family by pharmacognosy technique with GC–MS analysis

Yuzhu (Polygonati Odorati Rhizoma), Kangdingyuzhu (Polygonati Prattii Rhizoma), and zhugenqiyuzhu (Disporopsis Fuscopictae Rhizoma) are of the same family, but of different genera. They have all often used in Chinese Materia Medica (CMM) as Polygonati Odorati Rhizoma in China market. Three species of CMM are confused. For better application, we need to identify these plants accurately. This study use pharmacognosy technique and GC‐MS analysis, three species of CMM were authenticated. In macroscopic characteristics, the fruit of Polygonati Odorati Rhizoma is blue‐black, while the other two are maroon and dark purple orderly. Nodes of Polygonati Odorati Rhizoma are upward and light uplift, about 1 cm spacing, while the other are not. As for microscopic characteristics, the cortex of Polygonati Odorati Rhizoma only occupies about 1/5 of the radius of the transverse section with inconspicuous endodermis, which is much smaller than others. The type of vascular bundles of Polygonati Odorati Rhizoma is closed collateral, but the other is amphivasal. Raphides of calcium oxalate are scattered, but Raphides of the other two are like brooms and neat rows. GC–MS analysis of essential oil could provide different characteristics to distinguish three species. Twenty‐three compounds were identified from essential oil of Polygonati Odorati Rhizoma and the main components were n‐hexadecanoic acid (49.45%), while n‐hexadecanoic acid of the other two are 23.92% and 9.45%. The content of n‐hexadecanoic is strongly different. This research was aimed to establish a method by pharmacognosy and GC–MS analysis to identify three CMM and for providing scientifical data to ensure accuracy of origin of three species. Microsc. Res. Tech. 78:119–127, 2015. © 2014 Wiley Periodicals, Inc.     

QuEChERS结合气相色谱三重四极杆串联质谱法测定高粱中45种农药残留

该实验建立气相色谱三重四极杆串联质谱法（GC-MS/MS）结合改良的QuEChERS方法同时检测高粱中45种农药残留。高粱粉末加水浸润后,加入10 mL乙腈-乙酸乙酯（1∶1,V/V）溶液,加入WondaPak提取盐试剂包Ⅱ提取,取上清液加入WondaPak净化管Ⅲ净化,氮吹近干,定容至1 mL,基质内标法定量。在质量浓度为0.05～1.00 μg/mL范围内,各农药的线性关系良好,线性回归方程的相关系数（R2）均＞0.995,方法检出限为0.001 2～0.042 4 mg/kg。分别向阴性高粱样品中添加质量浓度为0.01 mg/kg、0.10 mg/kg和0.50 mg/kg的45种农药标准品,其平均加标回收率为76.32%～108.45%,精密度实验结果的相对标准偏差（RSD）为0.12%～10.95%。与其他农药残留检测方法比较,该方法具有前处理操作简单、重复性好、灵敏度高、降低分析成本等优势,适用于高粱样品中农药的高灵敏度快速检测。