用自动系统凯氏定氮仪测定生物制品中蛋白质含量

应用自动系统凯氏定氮仪测定人血白蛋白和人血丙种球蛋白的蛋白含量 ,重复性测定X % (n =10 )±SD分别为 2 0 45 %± 0 18%和 10 2 5 %± 0 12 % ;用硫酸铵、氨基乙酸和标准蛋白质控液作回收率试验R % (n =10 )±SD分别为 10 0 .2 4%± 0 5 7% ,99.89%± 0 43%和 10 0 5 0 %± 0 75 % ;用该法测定蛋白质含量与手工定氮法比较有良好相关性 ,总氮 (TN)相关系数r(n =2 6 )为 0 9999;非蛋白氮 (NPN)r(n =19)为 0 9946 ;蛋白氮 (PN)r(n =19)为 0 .9999。测定同批标准人血白蛋白 ,结果X % (n =2 0 )±SD为 5 5 3%± 0 14% ,与其参考标准值 5 5 4%± 0 12 %非常接近。因此 ,用该仪器法测定生物制品中的蛋白质含量准确可靠 ,且快速。     

丙烯酸甲酯分析方法“皂化—溴化法”的探讨

丙烯酸甲酯是我厂腈纶生产三大主要原料之一。所用原料须经分析合格后,才能投料生产。起初,我厂分析人员用溴化法测定其含量,结果为24.91％和27.02％,平行偏差甚大(两次平行测定的相对偏差要求不得大于±0.20％)。溴化法的分析原理是利用丙烯酸甲酯分子结构上的双键与溴起加成反应,生成1,2——二溴代丙酸甲酯:     

评定数据精密度的最大残差法

1 引言在分析化学中,一般采用环准偏差σ=((1/n)sum from i=1 to n (X_1-μ)~2)~(1/2) (1)来评定数据的精密度。这是因为概率论已经证明,当测量次数 n→∞时,测量值与总体平均值μ之差落在±σ范围内的概率为68.3％,落在±2σ范围内的概率为95.5％,落在±3σ范围内的概率为99.7％。这说明,σ越小,测量结果的分散程度就越小,测量结果的精密度也就越好。在实际测量中,由于测量次数 n 一般都是较小的有限值,而且总体平均值μ亦未知,因此在评定有限次测量结果的精密度时,通常采用下述贝塞尔公式。     

单氟磷酸钠洗必太加药牙膏的研制

近年来,国内加药牙膏发展很快。国内氟化钠牙膏生产较多,但随着放置时间延长防龋效果逐渐降低。因此国外把氟化钠牙膏列为D级,属于防龋效果较差的牙膏。据报道,单氟磷酸钠-洗必太复方药物牙膏,既防龋又脱敏。洗必太牙膏国内已有生产,但含单氟磷酸钠的以及含单氟磷酸钠-洗必太的两种加药牙膏的生产还未见报道。我厂从1975年起开始这项研制工作,到1981年7月取得满意结果。一、药物介绍1．单氟磷酸钠(Na2FPO3,简称MFP):是氟化物中防龋作用较好的药物,具有无毒     

KH550自组装活化法对木棉纤维化学镀镍的影响

先对木棉纤维(KF)进行亲水处理,再用4%(质量分数)硅烷偶联剂KH550在亲水KF表面自组装成膜得到KH550/KF,经镍活化后再进行化学镀镍–磷,得到Ni–P/KH550/KF轻质复合导电纤维。采用红外全反射仪(ATR)、X射线衍射仪(XRD)、扫描电镜(SEM)及能谱仪(EDS)分析了不同处理阶段纤维表层的化学结构、相结构、形貌及组成元素。结果表明:KH550被成功接枝到亲水KF表面。与直接活化法化学镀所得Ni–P/KF纤维相比,KH550自组装化学镀工艺所得Ni–P/KH550/KF复合纤维表面的Ni–P镀层更致密,电导率为(390.92±10.31)S/cm,有效密度为(3.990 2±0.031 2)g/cm3。     

非完全消化-火焰原子吸收光谱法测定芦荟中锰锌

将非完全消化法应用于火焰原子吸收光谱法 ,成功地测定了芦荟中的微量锰、锌。在低温下用高氯酸 硝酸 (1∶3,V/V)混合酸消解样品 ,再用乳化剂OP溶解消解过程中产生的油脂而配制成均匀、透明的样品溶液。以磺基水杨酸作为锰的释放剂 ,以空白溶液为参比 ,用工作曲线法测定。测定结果的相对标准偏差 <1 4 % ,测定结果与灰化法一致 ,相对误差± <1 7%。方法简便、准确     

TCDCANa的合成及抗菌抗炎作用研究

以鹅去氧胆酸(CDCA)和牛磺酸为基本原料合成了牛磺鹅去氧胆酸钠(TCDCANa),以萃取和重结晶法提纯,收率63.4%,w(TCDCANa)≥92%,以TLC和IR法确定了其结构。并将牛磺鹅去氧胆酸钠与鹅去氧胆酸钠(CDCANa)进行了抗菌、抗炎和镇咳对比实验。药效实验结果为:TCDCANa和CDCANa均具有抗革兰阳性菌作用(抑菌环直径分别为2.46±0.08cm和1.91±0.13cm),抗炎作用抑制率分别为(79.1±25.4)%和(71.2±23.1)%,镇咳作用减咳率分别为(29.1±5.6)%和(18.2±6.8)%,牛磺鹅去氧胆酸钠与鹅去氧胆酸钠间存在显著性差异。药效实验表明,TCDCANa具明显的镇咳、平喘和抗菌作用,其作用强于CDCANa。     

间苯二酚二羟乙基醚纯度的差示扫描量热法测定

介绍用差示扫描量热法(DSC)测定结晶物质纯度的原理和实验过程,讨论了Van'tHoff方程和DSC法对间苯二酚二羟乙基醚(HER)样品的适用性,用DSC法测定了不同厂家、不同批次的几种HER产品的纯度。当样品纯度(摩尔分数)高于98.0%时,平行测定结果之差≤0.1%(绝对差),测定结果与高效液相色谱法(HPLC)一致。在测定纯度的同时,测得HER的理论熔点(无限纯样品的熔点)为89.48±0.05℃,熔融热为39.4±0.7J/mol。     

牛磺鹅去氧胆酸钠的提取及与鹅去氧胆酸钠的药理作用比较

以500 mL鸡胆汁为基本原料,采用沉淀、过滤、减压蒸馏、真空干燥、抽提、重结晶法,制得了7.2 g结合型的牛磺鹅去氧胆酸钠(TCDCANa),以TLC及IR法确定其结构。并将其与鹅去氧胆酸钠(CDCANa)进行镇咳、平喘和祛痰作用对比实验。药理实验结果为:TCDCANa和CDCANa的镇咳作用减咳率分别为(29.1±5.6)%和(18.2±6.8)%;平喘作用解痉率分别为(79.9±22.8)%和(73.3±22.7)%,祛痰作用酚红排泌量分别为(1.601±0.391)μg/mL和(1.029±0.308)μg/mL,TCDCANa与CDCANa间存在显著性差异(P<0.01)。药理实验结果表明,TCDCANa具有明显的镇咳、平喘、祛痰和抗炎作用,其作用强于CDCANa。     

应用RPA2000橡胶加工分析仪进行胶料硫化模拟

利用RPA2 0 0 0橡胶加工分析仪的变温测试功能 ,模拟轮胎实际硫化过程中的温度变化。试验结果表明 ,模拟硫化结果与埋点式硫化测温所得实际温度 时间关系曲线基本吻合。由模拟硫化数据可知 ,硫化方案二 [内温　(174± 2 )℃ ,内压　 (2 8± 1)MPa ,外温　 (15 2± 2 )℃ ,外压　 (0 3 9± 0 0 3 )MPa ,硫化时间　 5 5min]的效果最佳 ,胎面胶和胎肩垫胶均可达到正硫化点 ,并保持在平坦区。     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

几种针状焦性能对比

针状焦分石油系和煤系两大类,这主要取决于针状焦的原料来源。在同一系列中由于原料不同和工艺条件不同 ,针状焦的各自性能也不相同。针状焦是生产超高功率石墨电极和高功率石墨电极的主要原料 ,针状焦的性能对石墨电极的质量有至关重要的影响。所以对针状焦性能以及其对石墨电极质量影响的研究十分必要的。以下是常用的几种进口针状焦和国产针状焦的性能对比。１原料性能分析对比原料试样包括４种针状焦 ,其中两种为进口针状焦：三菱针状焦和新日化针状焦;另两种为国产针状焦：鞍山针状焦和锦州针状焦。其中除锦州针状焦是石油系针状焦外…     

聚酰亚胺的合成法

本文评述了缩聚型聚酰亚胺的主要合成方法和近年来国际上在合成中所做的探索。