普鲁士兰法测定胡杨中植物多酚含量

首次采用普鲁士兰法对胡杨中植物多酚含量进行了研究.取胡杨枝粉碎后过40目筛,用丙酮水溶液提取液在45℃下浸提,提取液处理后用P-B法进行测定.首先从稳定性、最大吸收波长、线性关系、重复性和准确性等角度对P-B法进行了方法改进和验证.然后用改进的P-B法对胡杨枝提取液进行测定,测得结果是胡杨枝中总酚含量平均为1.191%、RSD为2.840%.     

Antioxidant activity of Citrus paradisi seeds glyceric extract

The antioxidant activity of Citrus paradisi (grapefruit) seeds glyceric extract dissolved in ethanol and in aqueous media was evaluated using three different methods: evaluation by DPPH assay, by 5-lipoxygenase assay and by luminol/xanthine/xanthine oxidase chemiluminescence assay. The total phenolic content was determined by the Prussian Blue method opportunely modified. The grapefruit seeds glyceric extract utilized as aqueous solutions demonstrated antioxidant properties better than those displayed by alcoholic solutions.     

杨树芽和芽胶中化学成分的分析

为测定加杨和香杨的芽和芽胶主要成分,对其活性成分进行了定性定量分析.定性分析结果表明,芽和芽胶含有黄酮、糖类、氨基酸和蒽醌类等成分.进一步采用索氏抽提法、硝酸铝-亚硝酸钠比色法、普鲁士蓝法、蒽酮-硫酸法、考马斯亮蓝法分别对其中粗精油、总黄酮、总酚、蛋白质、总糖、水溶性糖、多糖等进行定量分析,得出加杨芽胶粗精油含量为32.63%、总黄酮含量为33.33%、总酚含量为12.52%,香杨芽胶粗精油含量为36.73%、总黄酮含量为32.77%、总酚含量为26.39%.     

樟子松木材组织染色研究

【目的】拓展木材显微切片的染色方法。【方法】比较研究了番红(Safranine O)、固绿(Fast Green FCF)和阿利新蓝(Alcian Blue 8GX)三种染料对樟子松木材切片的染色效果。【结果】单一染料染色时,番红对木质化程度高的厚壁细胞上色效果较好,阿利新蓝对木质化程度低的薄壁细胞上染较好,固绿介于两者之间。两种染料复染时,番红-固绿无法实现不同细胞的区分,仅呈现番红的颜色;而番红-阿利新蓝可以区分厚壁和薄壁细胞,厚壁细胞(管胞和射线管胞)呈红色,薄壁细胞(射线薄壁细胞和泌脂细胞)呈蓝绿色。进一步通过冰乙酸为复染提供一个酸性环境,改进了番红阿利新蓝双染方法。当冰乙酸含量为13%~17%时,能达到理想的染色效果,能够更加清晰地区分厚壁和薄壁细胞。分别将番红、固绿和新蓝用于已解离的管胞染色,新蓝对管胞的染色效果最好,番红染色效果比新蓝略差,固绿染色效果远低于新蓝和番红。【结论】番红对木质化程度高的厚壁管胞染色效果最好;新蓝对木质化程度低的薄壁细胞染色效果最好。改进后的番红-新蓝双染能清楚地区分木材中的厚壁和薄壁细胞。木材细胞对不同种类染料的响应各异,同时也受染色介质影响。研究结果为木材切片细胞识别提供简单高效的新方法。     

紫外分光光度法测定酚醛胶合板中游离酚的含量

介绍了采用紫外分光光度法测定酚醛胶合板中游离苯酚含量的步骤。该方法是通过水蒸气蒸馏法提取苯酚，然后采用紫外可见分光光度法测定苯酚含量。结果表明，在波长269．70nm处、苯酚浓度在0-160μg／mL范围内吸光度与苯酚浓度呈线性关系，这为胶合板中游离苯酚含量的测定提供了新的方法。     

流动注射-4-氨基安替比林分光光度法测定水中挥发酚不确定度评定

应用测量不确定度评定理论,结合流动注射-4-氨基安替比林分光光度法对水中挥发酚测量不确定度进行全面分析,找出其影响不确定因素并对不确定度进行了评估,实验结果表明:流动注射在线蒸馏-4-氨基安替比林分光光度法测定水中挥发酚含量为0.050mg/L的样品,其扩展不确定度为3.92×10^-3mg/L,结合所有分量来看,样品的重复性引入的不确定度影响最大。同时,提高量器精密度也是降低不确定度的有效方法。     

Evaluation of Pluchea carolinensis extracts as antioxidants by the epinephrine oxidation method

Many methods have been used to evaluate synthetic and natural products as hydroxyl radical scavengers. In this study a spectrophotometric method to evaluate the scavenger activity of the hydroxyl radical produced in Fenton reaction is proposed. The oxidation of l-epinephrine to adrenochrome permitted the detection of the hydroxyl radical by spectrophotometry and its possible scavenging by hydroquinone, a well known antioxidant. The method was used to evaluate the antioxidant activity of Pluchea carolinensis leaves.     

单因素法考察川牛膝多糖提取工艺

采用单因素实验法,比较川牛膝多糖提取过程中,提取方式、提取温度、提取时间、提取料液比对川牛膝多糖得率的影响,用硫酸苯酚显色法与紫外分光光度法进行最优条件筛选。结果表明,川牛膝最佳多糖提取工艺为,超声波辅助提取法、提取温度60℃、提取料液比1∶20、提取时间1.5h时最优,提取率为47.12%。提取条件的不同川牛膝植物多糖提取率有较大差异,为后期工业化生产提供理论支持。     

自由基加成反应合成萜基甲硫醚

自由基加成反应应用于萜类化学为萜基甲硫醚的选择性合成提供了一条新的、简便的、有效的途径。在这一反应中，考察了反应时间、底物的比例、引发剂的种类及用量对转化率和产物的选择性的影响，并对反应的机理进行了探讨。     

Evaluating root growth potential of tree seedlings with an automated measuring system

Root growth of tree seedlings was quantified as change in root area index by using a video camera and digitizing area meter system that sums scanning line and root intersections. Number and total length of roots 0.5 cm and area index change were measured over a wide range of values. Linear regressions indicated that the automated and manual quantification methods yield essentially the same result. The automated method reduces measurement time, minimizes observer subjectivity, and estimates all new root growth. However, the equipment is costly, and the method does not provide information on the origin or size of new roots.     

紫叶稠李叶片色素测定及动态变化分析

用分光光度法对紫叶稠李叶片不同部位的花青素和叶绿素进行了测定，结果表明，随着时间的变化，不同部位叶片的花青素均呈现低-高-低的变化趋势，经方差分析，差异性不显著，说明紫叶稠李叶片花青素含量跟着生的部位关系不明显；同一部位的花青素含量远远大于叶绿素含量，这也是紫叶稠李叶片在整个生长季呈现紫红色的原因。     

新型无机高分子絮凝剂的制备研究

以粉煤灰为原料,采用酸溶、搅拌加热,静置熟化的方法制备了新型无机高分子絮凝剂聚合氯化铝铁,结果表明:絮凝剂制备的最佳提取条件是反应温度为90℃,料液比为5:17,反应时间为1.5h。     

A new synthetic method of 2,3,4,4'-tetrahydroxybenzophenone by boron trifluoride catalysis北大核心CSCD

A new synthesis of 2, 3, 4, 4'-tetrahydroxybenzophenone by boron trifluoride etherate catalysis was proposed in this paper. In the new method, high boiling-point petroleum ether was used as the reaction solvent to replace the poisonous and expensive 1, 1, 2, 2-tetrachloroethane. Although p-hydroxybenzoic acid, pyrogallic acid, boron trifluoride and petroleum ether were immiscible at room temperature, the reaction system could be gradually turned into brown oily solution in the heating and rapid mixing conditions. After a period of time, a large amount of yellow crystalline products were precipitated. According to the results of orthogonal experiments, the optimum reaction conditions were as follows:pyrogallic acid 0.05 mol, p-hydroxybenzoic acid 0.055 mol, catalyst 0.16 mol (20 mL), reaction temperature 110 ℃ and reaction time 1 h. Under this condition, the yield reached 83.24% and product purity 97.83%. The new method possessed many advantages, e.g., low toxicity, low cost, short reaction time, easy operation and the recycled catalyst. The product with 99.53% purity by recrystallization in water was identified as 2,3,4,4'-tetrahydroxybenzophenone by the combination of IR, NMR and EI-MS techniques.     

Rapid selection of catechin-rich tea trees (Camellia sinensis) by a colorimetric method

A rapid and efficient colorimetric method based on the use of Fast Blue B-salt (FBB) was established to select catechin-rich tea trees (Camellia sinensis L.). The catechin levels measured by the colorimetric method under optimized reaction conditions correlated closely with estimations by high-performance liquid chromatography (HPLC) analysis. The FBB colorimetric method was successfully used to classify 160 tea trees on the basis of their catechin contents into rich and poor lines. HPLC analysis of the FBB-selected tea tree extracts showed them to contain (−)-epigallocatechin 186 mg/g in tea tree line HR-29, (−)-epicatechin 43.7 mg/g in HR-82, (−)-epigallocatechin gallate 4.32 mg/g in HR-29, and (−)-epicatechin gallate 0.22 mg/g in HR-52. Classification of tea trees from the Hadong region into catechin-rich and -poor trees was independent of the growing season. Thus the FBB colorimetric method could find application as a reliable tool in screening and selection of tea trees on the basis of their catechin content.     

新型PVC热稳定剂马来海松酸锌的合成及表征

以马来海松酸酐和醋酸锌为原料，在无水乙醇中反应成功合成了新型PVC热稳定剂马来海松酸锌。研究了原料的摩尔比、反应时间、反应温度对产物的影响。结果表明：马来海松酸和醋酸锌摩尔比为1：3，反应温度为328K，反应时间为5h，反应得到高纯度的马来海松酸锌，产率可达93％以上。采用傅立叶红外光谱仪（FT-IR）、扫描电镜（SEM）、能谱仪（EDAX）和X一射线衍射（XRD）对产物进行了分析和表征，采用络合滴定法测定了产物中锌的含量。结果表明：利用该方法制得的马来海松酸锌属于三维网状化合物，产物中的-COO-与Zn2＋发生了化学键合。采用刚果红法与热烘法初步研究了马来海松酸锌热稳定剂对PVC的热稳定性能，结果表明：马来海松酸锌具有较好的热稳定性效果，且具有很好的初期着色性，是一种较好的环保型PVC热稳定剂。     

沙棘绕实蝇的生物学习性

[目的]沙棘绕实蝇严重危害沙棘果实,使沙棘种植地蒙受巨大经济损失。研究其生物学习性,可以为有效监测和控制沙棘绕实蝇提供理论指导。[方法]通过室内人工饲养和野外观察,研究沙棘绕实蝇的羽化、交尾、产卵、化蛹等生物学习性和野外发生动态。[结果]沙棘绕实蝇成虫在野外从6月中旬至8月上旬均可见到,发生量受天气影响较大;成虫主要集中在6:00—10:00羽化,羽化量占当日羽化量的81.3%,羽化高峰出现在8:00—9:00;化蛹时间主要集中在凌晨0:00—6:00,尤其是3:00—6:00钻出果实化蛹的幼虫数量较多,与其它时间段有明显差异;交尾时间主要集中在白天光照比较强的时间段,一天当中有两次交尾高峰,分别出现在12:00—13:00和16:00—17:00,交尾平均持续时长为239±11.86 min;沙棘绕实蝇产卵期沙棘果长径6.65±0.28 mm,宽径5.47±0.40 mm,一果只产一卵。[结论]沙棘绕实蝇在内蒙古磴口地区一年发生一代,幼虫钻蛀果实,蛹隐藏在地下,成虫期较短,防治工作应集中在成虫期进行。     

青梅核仁中苦杏仁甙的水解研究

采用异烟酸-吡唑啉酮分光光度法,对分别腌制22 d4、5 d、90 d、180 d、360 d的青梅腌制废液中苦杏仁甙水解后产生的氢氰酸含量进行测定。结果表明:异烟酸-吡唑啉酮分光光度法有良好的精密度和准确度;苦杏仁甙完全水解的条件为pH<2,蒸馏时间80 min;腌制180 d的青梅腌制废液中苦杏仁甙基本水解完全,氢氰酸质量浓度为83.3 mg.L-1。     

1,8-辛二醇的新合成方法研究

研究了一种简便的、易于工业化的制备1,8-辛二醇的新方法.以1,8-辛二腈为原料,先在硫酸催化下和甲醇反应高收率地得到辛二酸二甲酯,接着辛二酸二甲酯在硼氢化钠-甲醇-四氢呋喃体系中还原得到产物1,8-辛二醇,重点考察了还原剂硼氢化钠用量及反应时间对1,8-辛二醇收率的影响,得到了较佳的工艺条件:硼氢化钠与辛二酸二甲酯的...     

木竹屑炭化制脱臭剂的试验研究

将毛竹屑、绿竹屑、马尾松屑用坩埚装盛 ,放入干馏罐中 ,用加盖或敞开方式 ,在不同温度及保温时间下进行炭化制成脱臭剂 ,成品经纳氏试剂分光光度法测定其吸氨能力 ,以便从实验结果比较得出最佳工艺条件