海水pH标准物质的研制

提出一种更适合于海水pH测量的海水pH标准物质,对小批量制备该标准物质的制备方法及其定值方法进行探索研究。采用分光光度测定法测定海水pH标准物质的pH值,对该批海水pH标准物质分别抽取一定数量的样品采用F检验法和t检验法进行了均匀性检验和稳定性考核。结果表明,该批以人工海水为介质的海水pH标准物质混合均匀,常温条件下保存六个月是稳定的。     

水中硫酸根离子工作溶液的制备

以硫酸钠标准物质为原料,超纯水为溶剂,采用重量-容量法制备了水中硫酸根离子工作溶液.制备的水中硫酸根离子工作溶液采用离子色谱法分析,通过F-检验和回归曲线法对数据进行计算、方差分析和线性拟合,结果表明,该工作溶液具有良好的均匀性和稳定性.该文研制的水中硫酸根离子工作溶液的定值结果为1000 mg/L,相对扩展不确定度U...     

水中氟离子溶液标准物质的研制

文章以氟化钠标准物质为原料，超纯水为溶剂，采用重量-容量法制备水中氟离子溶液标准物质，介绍了水中氟离子溶液标准物质的研制方法。研制的水中氟离子溶液标准物质利用离子色谱法进行检测，分别采用F检验和回归曲线法进行均匀性和稳定性检验，方差分析和线性拟合结果表明该标准物质具有良好的均匀性和稳定性。选择国家二级标准物质采用同样的检测方法进行验证，结果表明制备的标准物质的方法准确度满足要求。研制的水中氟离子溶液标准物质的定值结果为1 000 mg/L,相对扩展不确定度U_rel=1%(k=2)。该标准物质量值准确，且具有溯源性，可用于水中氟离子测量过程的质量控制及分析方法的确认和评价。     

α-玉米赤霉醇溶液标准物质的研制

研制了浓度为0.1mg/mL的α-玉米赤霉醇标准溶液.研制过程包括纯物质定性分析、纯物质纯度定值、纯物质定值不确定度评定、溶液标准物质配制、封装和保存;均匀性检验、稳定性检验、溶液标准物质不确定度评定.定值结果表明,α-玉米赤霉醇溶液标准物质的定值过程、均匀性和稳定性均符合国家有关标准物质要求.目前,该溶液标准物质已批准为国家二级标准物质,可为相关部门提供检测标准.     

2,3,4-三氯苯甲醚标准物质研制与定值

研制了2,3,4-三氯苯甲醚标准物质,介绍了其制备与定值方法。将制备的2,3,4-三氯苯甲醚标准物质分装成500瓶样品,随机抽取其中11瓶做均匀性检验,经F检验和t检验,结果表明在95%置信范围内样品均匀性良好。按短期与长期稳定性分别进行稳定性检验,结果表明在常温20℃下,2,3,4-三氯苯甲醚的稳定期不少于12月。采用液相色谱法和差示扫描量热法2种不同原理的方法对2,3,4-三氯苯甲醚标准物质纯度定值及不确定度评定,并采用液相色谱标准添加的方法确认了2,3,4-三氯苯甲醚标准物质中的主要杂质2,3,6-三氯苯甲醚。定值结果为99.56%± 0.40%（k=2）。     

生乳冰点标准溶液系列的配制及不确定度分析

本文通过对天平称量、最小二乘法回归公式、标准物质均匀性及稳定性检验等各不确定度分量的分析,评定了重量法制备系列生乳冰点标准溶液的不确定度。     

膜分散微反应器制备高悬浮性纳米硫酸钡

以氢氧化钡和硫酸为原料,采用搅拌法和膜分散微反应器分别制备纳米硫酸钡颗粒和硫酸钡溶液,并采用XRD、TEM等手段进行测试和表征,研究常温老化和低温老化时纳米硫酸钡的生成机理,探讨氯离子和钠离子对硫酸钡性能的影响。结果表明:当氢氧化钡和硫酸的溶液浓度分别为0.5 mol/L、溶液体积流量为60 mL/min、低温老化温度为5℃时,可制备出粒径为32 nm、统计平均粒径为(24.4±5.3) nm的硫酸钡颗粒,静置24 h后的硫酸钡溶液的悬浮比高达98.1%,其性能优于常温老化法和传统搅拌法制备的;在低温老化条件下,硫酸钡颗粒生长缓慢,晶粒发育程度较低,XRD衍射峰峰强较弱,硫酸钡颗粒的粒径较小;纳米硫酸钡溶液的悬浮性与其zeta电位正相关,高悬浮性硫酸钡的zeta电位分布集中且均为正值,悬浊液稳定,分散性好;氯离子对硫酸钡颗粒粒径分布的影响较小;钠离子会显著降低硫酸钡溶液悬浮性,应避免钠离子的干扰。     

Stable dispersion of graphene solution prepared by hydrothermai reduction

以天然鳞片石墨为原料,用改进的Hummers法制备氧化石墨。超声分散制备氧化石墨烯溶液,通过加入不同量的水合肼调节溶液的pH值,再通过水热法热还原,制备了在水中稳定分散的石墨烯溶液。利用扫描电子显微镜（SEM）、高分辨透射电镜（HR-TEM）、拉曼光谱（Raman）、原子力显微镜（AFM）、X射线衍射分析（XRD）、zeta电位及光学显微镜对制备的样品进行了表征,研究了不同温度、pH值对石墨烯溶液稳定性的影响。     

高压釜热还原制备稳定分散的石墨烯溶液

以天然鳞片石墨为原料,用改进的Hummers法制备氧化石墨。超声分散制备氧化石墨烯溶液,通过加入不同量的水合肼调节溶液的pH值,再通过水热法热还原,制备了在水中稳定分散的石墨烯溶液。利用扫描电子显微镜(SEM)、高分辨透射电镜(HR-TEM)、拉曼光谱(Raman)、原子力显微镜(AFM)、X射线衍射分析(XRD)、zeta电位及光学显微镜对制备的样品进行了表征,研究了不同温度、pH值对石墨烯溶液稳定性的影响。     

烘干法水分测定仪用标准溶液的制备与标定

为制备符合烘干法水分测定仪检定水分误差用的5%±0.02%的氯化钠标准溶液，文章依据JJG 658—2010《烘干法水分测定仪》、GB/T 601—2016《化学试剂标准滴定溶液的制备》、GB/T 9725—2007《化学试剂电位滴定法通则》中的方法，对硝酸银标准滴定溶液、氯化钠标准溶液的制备与标定进行了详述，标定过程采用全自动电位滴定仪，并对硝酸银标准滴定溶液、氯化钠标准溶液测量不确定度进行了评定，分析结果表明，所制备的氯化钠标准溶液扩展不确定度为0.014%(k=2),满足MPE:±0.02%的技术要求，可用于烘干法水分测定仪的检定或校准，为烘干法水分测定仪用标准溶液的制备与标定提供了参考。     

Degradation Kinetics of Neostigmine in Solution

The degradation kinetics of neostigmine were studied in aqueous solutions with varied pH from 1.5 to 9.9 under accelerated storage conditions. The stability of neostigmine in solutions containing propylene glycol or polyethylene glycol 400 was also investigated. The reaction order of neostigmine in these aqueous and solvent systems followed pseudo-first-order degradation kinetics. The degradation rates of neostigmine under various buffer concentrations within the investigated pH range were obtained. They indicated that the degradation was independent of the species of buffering agent. Maximum stability of neostigmine was determined at pH 5.0 buffer species conditions. The activation energy could be estimated from the Arrhenius plot as 15.72 kcal/mole. The half-life of 883.7 days was estimated at room temperature in 0.1 M, pH 4.9 acetate buffer solution (μ = 0.5). Ultraviolet (UV) irradiation at 254 nm of the neostigmine solutions in pH 4.9 acetate buffer showed an accelerated degradation in comparison with light-protected samples. Incorporation of propylene glycol into the neostigmine solution at pH 4.9 enhanced the stability; however, an adverse effect on the stability of neostigmine was noted when a polyethylene glycol 400 solvent system was used.     

Degradation kinetics of neostigmine in solution

The degradation kinetics of neostigmine were studied in aqueous solutions with varied pH from 1.5 to 9.9 under accelerated storage conditions. The stability of neostigmine in solutions containing propylene glycol or polyethylene glycol 400 was also investigated. The reaction order of neostigmine in these aqueous and solvent systems followed pseudo-first-order degradation kinetics. The degradation rates of neostigmine under various buffer concentrations within the investigated pH range were obtained. They indicated that the degradation was independent of the species of buffering agent. Maximum stability of neostigmine was determined at pH 5.0 buffer species conditions. The activation energy could be estimated from the Arrhenius plot as 15.72 kcal/mole. The half-life of 883.7 days was estimated at room temperature in 0.1 M, pH 4.9 acetate buffer solution (mu = 0.5). Ultraviolet (UV) irradiation at 254 nm of the neostigmine solutions in pH 4.9 acetate buffer showed an accelerated degradation in comparison with light-protected samples. Incorporation of propylene glycol into the neostigmine solution at pH 4.9 enhanced the stability; however, an adverse effect on the stability of neostigmine was noted when a polyethylene glycol 400 solvent system was used.     

魔芋葡甘露聚糖/纳米ZnO复合涂膜对香蕉常温保鲜效果的影响

目的探讨魔芋葡甘露聚糖/纳米ZnO复合涂膜对常温贮藏香蕉保鲜效果的影响,为香蕉的采后常温保鲜贮藏提供新途径。方法以巴西蕉为实验材料,采用KGM涂膜液(A组)和KGM/纳米ZnO复合涂膜液(B组)等2种可食性涂膜液对香蕉进行涂膜处理,以不做任何处理为对照(CK组),置于夏季常温(32±2)℃下贮藏,每天取样测定果实的好果率、褐变指数、质量损失率、可溶性固形物含量、Vc含量等指标。结果在整个贮藏期间,与KGM涂膜和对照组相比,KGM/纳米ZnO复合膜能显著维持香蕉的好果率,抑制香蕉的褐变,降低香蕉在贮藏期的质量损失率,减少可溶性固形物和维生素C等营养物质的损失。结论 KGM/纳米ZnO复合涂膜液对采后香蕉的常温贮藏效果最好,能够维持香蕉较好的贮藏品质。     

氧化淀粉胶黏剂的交联改性及其性能研究

用玉米淀粉与过硫酸铵反应制备了氧化淀粉胶黏剂,再与二羟甲基双氰胺(DMDCD)进行交联反应,制备了一种交联改性氧化淀粉胶黏剂。采用红外光谱对样品进行了表征,并讨论了交联改性对氧化淀粉胶黏剂耐水性和贮存稳定性的影响。实验结果表明:DMDCD改性提高了淀粉胶黏剂的耐水性与贮存稳定性;当过硫酸铵质量分数为淀粉质量的1.5%,DMDCD质量分数为淀粉质量的3%时,交联改性氧化淀粉胶黏剂的贮存稳定性在45 d以上,其耐水时间、黏度分别为102 h和1680 mPa.s;红外分析证实了DMDCD与氧化淀粉发生了交联反应。     

高温过饱和硝酸铵溶液的爆炸危险性分析

为了研究过饱和硝酸铵（AN）溶液的爆炸特性,采用联合国隔板试验研究了不同状态过饱和AN溶液的爆轰特性。结果显示:对于常温过饱和AN溶液,当w(水)≤4%时,在联合国隔板试验1(a)中,试验后钢管完全破裂或验证板发生穿孔,即样品能传播爆轰;在联合国隔板试验2(a)中,试验后钢管部分撕裂或保持完好,验证板轻微变形,有大量样品残余,显示样品对爆炸冲击波刺激不敏感。对于140 ℃过饱和AN溶液,在联合国隔板试验2(a)中,当w(水)≤3.0%时,试验后样品钢管完全破碎,验证板穿孔,即样品在该试验条件下对爆炸冲击波作用敏感,表明过饱和AN溶液具有爆炸性,且温度升高会显著提高其爆炸危险性。     

Pre-formulation and chemical stability studies of penethamate, a benzylpenicillin ester prodrug, in aqueous vehicles

Penethamate (PNT) is a diethylaminoethyl ester prodrug of benzylpenicillin used to treat bovine mastitis via the intramuscular route. Because of its instability, PNT products must be reconstituted before administration and the reconstituted injection has a short shelf life (7 days at 2-8°C). The purpose of this paper was to investigate whether the stability of PNT can be improved in order to achieve a chemically stable ready-to-use aqueous-based PNT formulation or at least to extend the shelf life of the reconstituted suspension. A chemical stability study of PNT in aqueous-based solutions as a function of pH, buffer strength, solvent mixtures and temperature, supported by studies of its solubility in mixed solvents, allowed predictions of the shelf life of PNT solution and suspension formulations. PNT degraded in aqueous solutions by several pathways over the pH range 2.0-9.3 with a V-shaped pH-rate profile and a minimum pH of around 4.5. The stability of PNT solutions in mixed solvents was greater than in aqueous solutions. For example, in propylene glycol:citrate buffer (60:40, v/v, pH 4.5), the half-life of PNT was 4.3 days compared with 1.8 days in aqueous buffer. However, solubility of PNT in the mixed solvent was higher than that in aqueous solution and this had an adverse effect on the stability of suspensions. By judicious choosing of pH and mixed solvent, it is possible to achieve a storage life of a PNT suspension of 5.5 months at 5°C, not sufficient for a ready-to-use product but a dramatic improvement in the storage life of the reconstituted product.     

硝酸铵溶液的爆炸危险性及储运安全条件研究

为确定硝酸铵溶液的爆炸危险性及温度、浓度等储运安全条件,采用克南试验、绝热量热试验、联合国隔板试验及析晶特性试验等研究了热分解和殉爆两种情况下硝酸铵溶液的爆炸危险性及安全控制条件。结果表明:140 ℃时,硝酸铵溶液含水质量分数小于4%,为爆炸物;含水质量分数为4%-10%时,则具有爆炸性;含水质量分数大于10%时,不具有爆炸性。硝酸铵质量分数为90%以上时,硝酸铵溶液的起始放热温度在210～230 ℃范围内,T_D24最低为151 ℃。110～140 ℃区间内,高温硝酸铵溶液的冲击波感度与溶液析晶状态有关,大量析晶会发生殉爆。因此,硝酸铵溶液中硝酸铵的质量分数应控制在93%以内;温度上限应控制在140 ℃以内;温度控制下限应根据硝酸铵溶液的析晶温度确定。     

热处理温度对海水循环泵叶轮用双相不锈钢冲击性能的影响

针对海水循环泵叶轮的服役条件,利用烟台台海玛努尔核电设备有限公司提供的材料,研究了热处理工艺对GX2GrNiMoN22-5-3双相不锈钢冲击性能的影响。结果表明,双相不锈钢的冲击性能在常温下随固溶温度的升高而逐渐下降,并且在1120～1160℃固溶温度范围内下降明显,在1160～1200℃温度范围内下降趋势缓慢。铁素体含量测试表明,随固溶温度的升高,铁素体的变化趋势与冲击功的变化趋势具有良好一致性,表明固溶温度升高铁素体含量降低,是冲击功减小的重要原因。对冲击断口形貌进行观察,冲击断口以韧窝型断裂为主。     

Method for trace level analysis of C8, C9, C10, C11, and C13 perfluorocarbon carboxylic acids in water

A method was developed for the trace level analysis of pentadecafluorooctanoic acid (C8), heptadecafluorononanoic acid (C9), nonadecafluorodecanoic acid (C10), heneicosafluoroundecanoic acid (C11) and pentacosafluorotridecanoic acid (C13) in water. Samples were concentrated by solid-phase extraction (SPE) before analysis by combined liquid chromatography/electrospray tandem mass spectrometry (LC/MS/MS). A surrogate standard, 9-hydrohexadecafluorononanoic acid (9H), was used to monitor recovery. The lower limit of quantitation (LLOQ) for C8, C9, C10, C11, and C13 was determined to be 25 ng/L in water. The specificity of the method was established by showing no significant interferences (<20% of the LLOQ standard) in control samples of well, stream, spring, tap, omnisolve, and type I water at the retention time of the target analytes. The linearity of the method was determined; the coefficients of determination for the five calibration curves generated were all >0.985. Good within-day and between-day accuracy and precision were demonstrated. Extracts and standards were shown to be stable after remaining at room temperature for approximately 24 h. Samples fortified with C8, C9, C10, and C11 were shown to be stable after remaining at room temperature for 14 days before extraction. Samples fortified with C13 were shown to be stable after remaining at room temperature for 7 days before extraction. Fortified samples, extracts, and standards demonstrated stability after being stored in a refrigerator for 14 days for all analytes. Long-term storage stability was demonstrated for methanolic stock solutions.     

海藻接枝丙烯酸高吸水性树脂的制备及性能研究

采用海藻为原料与丙烯酸接枝共聚制备了高吸水性树脂。通过红外光谱(FT-IR)分析了产物的结构。考查了丙烯酸中和度、丙烯酸用量、引发剂和交联剂的用量以及反应温度等各因素对产物吸水率的影响。结果表明,所得树脂的吸水率可达618g/g,吸盐水率(0.9%的NaCl水溶液)达到120g/g,其吸水速率适中,热稳定性和在室温下的保水性均较好,是一种新的环保型高吸水性树脂。FT-IR初步表明了丙烯酸与海藻的接枝聚合作用。