Simplified quantitative analysis method and its application in the insitu synthesized copper-based azide chips

Copper-based azide(Cu(N_(3))2 or CuN_(3),CA)chips synthesized by in-situ azide reaction and utilized in miniaturized explosive systems has become a hot research topic in recent years.However,the advantages of in-situ synthesis method,including small size and low dosage,bring about difficulties in quantitative analysis and differences in ignition capabilities of CA chips.The aim of present work is to develop a simplified quantitative analysis method for accurate and safe analysis of components in CA chips to evaluate and investigate the corresponding ignition ability.In this work,Cu(N_(3))2 and CuN_(3)components in CA chips were separated through dissolution and distillation by utilizing the difference in solubility and corresponding content was obtained by measuring N_(3)-concentration through spectrophotometry.The spectrophotometry method was optimized by studying influencing factors and the recovery rate of different separation methods was studied,ensuring the accuracy and reproducibility of test results.The optimized method is linear in range from 1.0-25.0 mg/L,with a correlation coefficient R^(2)=0.9998,which meets the requirements of CA chips with a milligram-level content test.Compared with the existing ICP method,component analysis results of CA chips obtained by spectrophotometry are closer to real component content in samples and have satisfactory accuracy.Moreover,as its application in miniaturized explosive systems,the ignition ability of CA chips with different component contents for direct ink writing CL-20 and the corresponding mechanism was studied.This study provided a basis and idea for the design and performance evaluation of CA chips in miniaturized explosive systems.

Mechanistic Study and Kinetic Determination of Cu(Ⅱ) by the Catalytic Kinetic Spectrophotometric Method

A highly sensitive and selective catalytic kinetic spectrophotometric method for the determination of Cu(Ⅱ) is proposed. It is based on the catalytic effect of Cu(Ⅱ) on the oxidation of glutathione(GSH) by potassium hexacyanoferrate(Ⅲ) in acidic medium at 25.0℃. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of oxidant at 420 nm using the fix-time method. Under the optimum conditions, the proposed method allows the determination of Cu(Ⅱ) in a range of 0-35.0 ng m L^(-1) with good precision and accuracy and the limit of detection is down to 0.04 ng m L^(-1). The relative standard deviation(RSD) is 1.02%. The reaction orders with respect to each reagent are found to be 1, 1/2, and 1/2 for potassium hexacyanoferrate(Ⅲ), glutathione and Cu(Ⅱ) respectively. On the basis of these values, the rate equation is obtained and the possible mechanism is established. Moreover, few anions and cations can interfere with the determination of Cu(Ⅱ). The new proposed method can be successfully used to the determination of Cu(Ⅱ) in fresh water samples and seawater samples. It is found that the proposed method has fairly good selectivity, high sensitivity, good repeatability, simplicity and rapidity.

Two spectrophotometric methods for simultaneous determination of some antihyperlipidemic drugs

Two simple, accurate, precise and economic spectrophotometric methods have been developed for simultaneous determination of Atorvastatin calcium (ATR) and Ezetimibe (EZ) in their bulk powder and pharmaceutical dosage form. Method (I) is based on dual wavelength analysis while method (II) is the mean centering of ratio spectra spectrophotometric (MCR) method. In method (I), two wavelengths were selected for each drug in such a way that the difference in absorbance was zero for the second drug. At wavelengths 226.6 and 244 nm EZ had equal absorbance values; therefore, these two wavelengths have been used to determine ATR; on a similar basis 228.6 and 262.8 nm were selected to determine EZ in their binary mixtures. In method II, the absorption spectra of both ATR and EZ with different concentrations were recorded over the range 200-350, divided by the spectrum of suitable divisor of both ATR and EZ and then the obtained ratio spectra were mean centered. The concentrations of active components were then determined from the calibration graphs obtained by measuring the amplitudes at 215-260 nm (peak to peak) for both ATR and EZ. Accuracy and precision of the developed methods have been tested; in addition recovery studies have been carried out in order to confirm their accuracy. On the other hand, selectivities of the methods were tested by application for determination of different synthetic mixtures containing different ratios of the studied drugs. The developed methods have been successfully used for determination of ATR and EZ in their combined dosage form and statistical comparison of the developed methods with the reported spectrophotometric one using F and Student’s t-tests showed no significant difference regarding both accuracy and precision.

IMPROVEMENT OF FLUORIMETRIC AND UV－VISIBLE SPECTROPHOTOMETRIC ASSAY METHODS FOR MEASURING NITRIC OXIDE AND／OR EDRF IN BLOOD

The increasing importance of endothelium-derived relaxing factor(EDRF),which has now been identified as nitric oxide (NO),has been underscored by the eltlcidation of its role'in a growing number of normal and pathophysiological processes. Therefore techniques for detection of nitric oxide should serve as useful tools in defining the role of nitric oxide to these processes.We have improved a simple, sensitive assay methods for determination of nitric oxide in blood, tissue, and other body fluids both by fluorometric and by ultraviolet-visible spectrophotometric measurements. Data obtained by floores cence and by UV-visible assay were correlated well (r=0. 9938, P<0. 0001 ).Linearity:0.1￣ 100μmol/L,r =0.9996,P<0.0001. The minimum detection limit were < 10pmol/L. Within-and between-run CVs were 2. 48%and 4. 62% (n = 10),respectively.Reference values for healthy adults(n=40) were(9.82 ± 1. 57) pmol/L. In conclusion:the methods is sensitive, specific,and precise. It is fairly rapid and simple to perform andrequires no pretreatment of sample, i. e., plasma and urine.The value can be obtained by fluorimeter and/or UV-visible spectrophotometer.The present method is sufficiently rapid and simple to make this a practical choice for many laboratories.

Simple Spectrophotometric Methods for the Determination of Meloxicam in Presence of Its Degradation Products

To develope two simple and accurate spectrophotometric methods for the determination of meloxicam( I )in presence of its degradation products, 5 -methyl -2 -aminothiazole ( II )and benzothiazine carboxylic acid( Ill ). Method:Both methods are based on the formation of chelate complexes of the studied drug with uranyl acetate and ferric chloride at room temperature in a methanolic medium. Results:The resulting complexes are stable for 24 hrs and show absorption maxima at 406 nm and 580 nm for uranyl and ferric complexes respectively. These methods are applicable over the concentration ranges of 10 -100 and 37.5 -300 p^g ~ mL-1 with mean recoveries of (99.44 ~ 0. 48 ) % and (99. 42 ~ 0. 45 ) %, and molar absorptivity of 4.67 x 103 and 1. 029 x 103 respectively. Conclusion:Both methods are proved to be stability indicating as no interference was observed with the degradation products. The proposed methods were successfully applied to the determination of the frug in bulk powder, laboratory prepared mixtures containing different percentages of degradation products of the drug in bulk powand pharmaceutical dosage

亚甲蓝分光光度法测定水中阴离子表面活性剂含量的方法改进

对亚甲蓝分光光度法(GB 7494—1987)测定水中阴离子表面活性剂含量进行了方法改进。以毒性相对较小的二氯甲烷取代三氯甲烷作为萃取剂,试管取代分液漏斗,利用振荡器进行萃取。结果表明:改进方法的最佳萃取时间为1.5 min,单个样品的分析时间在10 min以内;十二烷基苯磺酸钠标准曲线的线性范围在2.0 mg·L^(-1)以内,检出限(3s/k)为0.0297 mg·L^(-1);对十二烷基苯磺酸钠标准溶液重复测定6次,测定值的相对标准偏差(n=6)均小于9.0%;对空白样品进行加标回收试验,回收率为95.0%~99.1%。

紫外分光光度法测定歧化松香中去氢枞酸含量的干扰因素研究

利用液相色谱仪、制备液相色谱仪、气相色谱质谱联用仪,对歧化松香(DR)中去氢枞酸(DA)紫外光谱测定方法的干扰因素进行了详细研究。测定的市售不同省份的5个样品中有2个主要干扰物质,进一步定性,确定干扰物质1为6,8,11,13-枞四烯酸(ATA),干扰物质2为混合物,主要检出物为去氢枞醛(D)和枞酸(AA)。采用二阶导数光谱法和偏最小二乘(PLS)法对紫外光谱数据进行分析,以消除去氢枞酸紫外分光光度法的干扰,结果表明:PLS法比二阶导数光谱法误差更小,能够同时消除多种干扰因素,使测试结果更加接近真实值。

乙二醇锑中锑含量分析方法比较

介绍了聚酯催化剂乙二醇锑中锑含量分析方法,从分析技术原理、实验设备材料、影响因素、经济适用性等方面进行了对比分析。对比结果表明,3种分析方法适用于不同的分析条件,不同的生产企业和检测单位可以根据自身的需要建立适合自己企业的分析方法。文章的研究内容对聚酯催化剂乙二醇锑中锑含量分析方法的选择具有一定的指导意义,可为相关领域的研究提供一定的参考。

希托夫法测定离子迁移数的影响因素探究

离子迁移数作为物理化学课程中电化学部分的一个重要概念,其测定实验被设置在多所高校的物理化学实验课程中。文献调研及过往教学实践表明,使用希托夫(Hittorf)法测定的离子迁移数,结果与文献值有较大出入。为了降低测定误差,以及探究测试结果的影响因素,本实验从溶液装液量控制、断液断电顺序、计算电量的数据来源三个方面进行改进,尽可能降低实验操作和浓度测定导致的误差,从而分析真正影响测试结果的因素。实验表明,当采用电流乘以时间作为电量的数据来源,且采用阴极区溶液计算离子迁移数时,所得结果更接近实验参考值。

锗元素测定方法综述

锗在国防工业、航空航天和通信等领域中具有战略性意义,锗含量的测定对于保证材料质量和满足国际标准至关重要。对锗含量测定方法的多种技术进行了综述,包括分光光度法、原子荧光光谱法、原子吸收光谱法、电感耦合等离子体原子发射光谱法、电感耦合等离子体质谱法以及滴定法等。在每种检测方法的介绍中,详细探讨了方法的原理、前处理步骤以及应用范围,并分别总结了各方法的优势和不足。最后,强调了锗含量测定方法的意义,特别是在满足出口监管和促进科学研究方面的作用。同时对锗元素的测定方法进行了展望,为未来的发展提供了参考方向。

星点设计-响应面法优化毛连菜总有机酸提取工艺

目的:优选毛连菜总有机酸提取工艺。方法:在单因素试验基础上,以液料比、提取时间及乙醇体积分数为自变量,以有机酸提取率为因变量,采用星点设计-响应面法优化毛连菜总有机酸提取工艺。结果:毛连菜总有机酸的最佳提取工艺为:液料比29∶1(mL·g^(-1))、乙醇体积分数67%、提取时间43 min。验证试验测得总有机酸提取率为(1.65±0.02)%,(n=3,RSD=0.92%),与模型预测值结果接近。结论:优化建立的提取工艺简单,工艺参数可靠,提取效果良好,为毛连菜总有机酸的后续研究奠定基础。

Fe(Ⅲ)配合物法快速测定表面处理槽液中的苹果酸含量

建立了一种表面处理槽液中苹果酸的快速测定方法,以甲酸作为辅助配体,并控制溶液pH 2.5~2.7,使苹果酸与Fe(Ⅲ)形成稳定的配合物,在波长372 nm处具有特征的紫外吸收峰。配合物的吸光度与苹果酸的浓度呈良好的线性关系,方法的线性范围为0.05~0.30 g/L,最低检测限为0.01 g/L。与现有技术相比,该方法操作简便、反应时间短、即混即测、易于自动化、抗干扰能力较强、不受表面处理槽液中常见金属离子和阴离子的影响、定量结果准确可靠,可为确保工业生产线的质量控制提供高效的技术支撑。

响应面法优化提取瓜蒌皮中总三萜的研究

目的 探讨用醇提法提取瓜蒌皮中总三萜化合物。方法 以瓜蒌皮为研究对象,以乙醇为溶剂,采用紫外分光光度法对瓜蒌皮中总三萜化合物的含量进行测定。通过单因素实验研究液固比、提取温度、提取时间、乙醇浓度对总三萜提取率的影响,在单因素实验的基础上,采用Box-Behnken Design响应面分析法研究乙醇提取的最佳工艺条件。结果 冷凝回流提取的最佳条件为液固比51 mL/g,乙醇浓度83%、提取时间70 min、提取温度90℃;在此工艺条件下,总三萜的最佳提取率为2.324%。结论 研究结果与预测值基本一致,因此该模型可靠。

分光光度法测定生活饮用水中六价铬的方法验证

本文采用《生活饮用水标准检验方法第6部分:金属和类金属指标》(GB/T 5750.6—2023)中二苯碳酰二肼分光光度法对生活饮用水中六价铬的方法进行验证研究,验证内容主要包括标准曲线线性关系、方法检出限、测定下限、准确度、精密度等方面,并对以上性能指标的测定结果进行分析,结果表明:标准曲线相关系数为0.9999;检出限为0.0007 mg/L;测定下限为0.0021 mg/L;精密度为0.3%~0.8%;加标回收率为95%~102%,所有性能指标验证结果均能满足方法标准要求,本实验室具备采用二苯碳酰二肼分光光度法测定生活饮用水中六价铬的能力。

地质样品银、铜、铅、锌测定过程中应用试液称重火焰原子吸收分光光度法的研究

本文应用试液称重火焰原子吸收分光光度法对地质样品银、铜、铅、锌元素进行测定。通过试验发现该方法不仅操作起来非常简便,而且测试速度快,所用试剂较少,试验操作不会对人员和环境造成伤害。另外,这一方法通过国家标准物质测定验证,获得的结果能够满足地质规范相关要求,在地质样品大批量测定过程当中可以推广应用。

碱性过硫酸钾-紫外分光光度法测定水质总氮方法的改进

水质总氮是指示水体富营养化的重要标志物,因此,开发测定水体中总氮的准确方法,对研究水体中的污染物来源、污染程度及总氮的地球化学循环过程具有重要意义。测定水质样品中的总氮,通常采用碱性过硫酸钾-紫外分光光度法,但该法对空白吸光度有严苛的要求,空白吸光度一旦超过0.030,就有可能导致测定结果严重偏低,其中,过硫酸钾的纯度和存放时间可能对测定结果影响最大;同时,采用比色管捆绑方式高温高压消解水质样品,导热较慢,消解时间偏长,捆绑时一旦比色管上的标签或记号脱落,容易导致样品混乱;样品保存条件不当也很容易造成测定结果偏低。为提高水质样品中总氮测定结果的准确性和效率,本文通过对国内外不同厂家生产的过硫酸钾进行总氮空白吸光度和存放时间对比实验,然后对两种消解方法进行消解时间对比实验,最后,对比了两种不同水质样品保存方法对测定结果的影响。对比实验结果表明:国产优级纯碱性过硫酸钾存放时间在30天内,其水质总氮空白吸光度均小于0.030;在124℃条件下,使用插置法消解样品,只用20min就能使样品消解完全;对酸化后的水质样品,其保质期从1天延长至7天。研究认为,选用国产优级纯过硫酸钾和改良过的插置法消解水质样品,与捆绑法相比,其水质总氮检出限更低,消解效率更高,且不容易出现互相污染和样品错位等情况,提高了水质总氮测定的准确度。

低浓度聚丙烯酰胺含量的检测及溶液离子的影响

处理后选矿废水中残余的聚丙烯酰胺(PAM)影响回水水质及其回用,本文为建立一种低检出限的低浓度PAM快速检测方法,在190~300 nm波长范围内建立了4种类型及分子量不同PAM的紫外吸收光谱,研究了不同浓度K^(+)和Ca^(2+)对PAM浓度检测的影响,并通过原子力显微镜(AFM)分析了PAM分子构象的变化.结果表明,4种类型的PAM峰值吸光度均在波长194 nm处测得,PAM浓度与吸光度之间具有强线性关系(R^(2)>0.98),检出限均低于0.1 mg·L^(-1),但PAM类型影响其浓度与吸光度的线性关系.随着K^(+)和Ca^(2+)浓度的增加,PAM溶液吸光度特征峰的强度逐渐降低并降速减缓,最大吸收波长不断红移,分别沉积在二氧化硅和金基底的APAM-3与CPAM-12的表面形貌粗糙度分别随K^(+)和Ca^(2+)浓度的增加而增大,说明PAM分子链在溶液中的构象逐渐变卷曲,使紫外光谱特征吸收峰的峰值降低,10、100 mmol·L^(-1) K^(+)与1、10 mmol·L^(-1) Ca^(2+)对PAM构象变化的影响程度基本相同.本研究实现聚丙烯酰胺的快速定量检测,对开展选矿水处理中聚丙烯酰胺的迁移规律研究具有重要意义.

紫外分光光度法测定工作场所空气中油雾

建立溶剂洗脱-紫外分光光度法测定工作场所空气中油雾的方法。用玻璃纤维滤膜采集工作场所空气样品,经正己烷超声洗脱,将洗脱液置于1 cm石英比色皿中,在225 nm波长处用紫外分光光度计测定。油雾的质量浓度在0~30.0μg/mL范围内与吸光度线性关系良好,线性相关系数为0.9997,方法检出限为0.3μg/mL,定量限为0.8μg/mL。以采集45 L空气样品计,最低检出质量浓度为0.07 mg/m^(3),最低定量质量浓度为0.18 mg/m^(3)。测定结果的相对标准偏差为1.8%~4.5%(n=6),样品加标回收率为95.7%~104.7%。该方法操作简单,试剂耗材成本低,对实验人员身体危害较小,且检出限低,精密度、准确度、样品稳定性均能够满足职业卫生检测方法要求,适用于工作场所空气中油雾的测定。

工业废水中氟离子测定方法比对

对GB/T 7484-1987《水质氟化物的测定离子选择电极法》和低含量氟的测定方法HJ 488-2009《水质氟化物氟试剂分光光度法》进行了方法验证,从样品保存、标准曲线线性、检出限、加标回收率、精密度、准确度、样品测定、方法对比等方面进行了条件试验研究。试验表明:氟试剂分光光度法适合水样洁净,无干扰项样品的测定,且操作繁琐、耗时较长;离子选择电极法测定范围较广,结果准确,能够快速指导生产,是一种既经济又准确的氟化物检测方法。

水泥原材料中总铬检测标准方法验证

为了有效控制水泥中重金属铬,构筑健康的人居环境,准确地检测限制水泥原材料中总铬是非常必要的。对标准方法《水泥原材料中总铬的测定方法》,采用分光光度法测定水泥原材料中总铬含量方法进行了验证。通过分析与研究所测得的线性关系、检出限、精密度,并且计算得出该方法检出限为0.0089mg/L,相对误差均能满足要求,表明该方法适用于现有水泥生产过程中原材料的检测,在实验室内准确可行。同时对检测实验过程中出现的细节问题提出了操作建议,有助于检测过程细节的规范、完整、准确。