X-射线荧光光谱成型滤纸片法测定原油中的钒、镍、锰和铜

本文介绍了一个以有机金属标准试剂配制标准样品,成型滤纸片作为标样与试样的支撑材料,点滴法制备样片,用透空照射法直接测定原油中V、Ni、Mn和Cu的X-射线荧光光谱法。方法检出限低,制样与测量精度小于6％,标准加入回收率较好,具有简单、快速、实用的特点。     

SD40硅烷偶联剂中硫含量的测定

对SD40硅烷偶联剂试样进行消解处理、加热至高氯酸冒烟,使原硅脱水凝聚形成沉淀除去,用硫酸钡重量法测定SD40硅烷偶联剂中硫的含量,此法的相对标准偏差低于0.15％,标样回收率为99.8％～100.2％。     

原子荧光光谱法测定城市污水中的铅

研究了用氢化物原子荧光法测定城市污水中铅的方法。对样品前处理方法进行了筛选,在选定的最佳实验条件下,方法检出限为０．５５μｇ／Ｌ。标样含量在２５μｇ／Ｌ时,其变异系数为０．３％。以实际样品测定,加标回收率为９６％－１０１％,变异系数在２％以内,证明本方法测定污水中的铅切实、有效。     

冷原子吸收光谱法测定化妆品中汞

应用冷原子吸收光谱法测定化妆品中痕量汞,在所选最佳测定条件下,测得方法的检出限为0．1μg·kg-1,测定下限为0．40 mg·kg-1,取4．0μg·L-1汞标液作精密度试验,算得相对标准偏差为0．6％,用标准加入法作回收率试验,所得结果在92％～97％之间。     

离子选择电极分析法测定聚乙烯中氟

提出了一种新的离子选择性电极分析方法,即体积校正-等电位差-标准加入法,并用于聚乙烯中氟含量的测定。对样品干法灰化条件进行了考查。有机化合物标样回收率为98.0％,聚乙烯分析结果的相对标准偏差为1.6％。方法简便、准确。     

共价氢化物与汞离子反应的研究 Ⅰ 痕量锑高灵敏度的分析新方法

本文提出了一个氢化物发生一冷原子荧光法间接测定痕量锑的新方法。考察了各种实验条件,并将此法用于水及沉积物标样分析,结果令人满意,对水中锑检出限为0.1μg/L,回收率96％～102％。     

火焰原子吸收光谱法测定电解锰电解液中铁钴镍

在标准溶中加入匹配的硫酸铵和硫酸锰溶液,用氨水调节ＰＨ至中性后,用火焰原子吸收光谱法直接测定电解锰电解液中铁、钴和镍含量,获得了满意的效果,其倍比试验,标准曲线法、标准加入法结果相吻合,样品加标回收率为９４．８％－１０６．４％,相对标准偏差为２．１％－３．１％。方法简便、快速,运用于工厂快速分析。     

微波消化技术在蔬菜微量元素测定中的应用

使用家用微波炉在聚四氟乙烯密闭罐中，用硝酸和过氧化氢分解脱水蔬菜胡萝卜粒，火焰原子吸收光谱法测定铜、铁、镁、镍、锌微量元素。方法快速、简便，灵敏度高，再现性好，相对标准偏差为0．2％～1．5％，回收率为95．0％～110．6％。     

塞曼火焰原子吸收光谱法直接快速测定白砂糖中的铜及铅含量

采用标准加入法,消除了基体,背景和粘度的影响,直接用塞曼火焰原子吸收光谱法测定白砂糖中的铜及铅含量。此法具有简便、快速、灵敏度高等优点,相对标准偏差铜为０．６１％－１．９％,铅为０．９４％－３．５％;回收率铜为９８．４％－１０２％,铅为９７．４％－１０４％。     

废催化剂中钯的光谱测定

失去活性的钯催化剂是以三氧化二铝为主体(97％以上),含有部分碳、二氧化硅以及少量铁、镁等常见元素的混合物,其中含有一定量的钯。催化剂中钯的测定常用化学分析。用光谱法测定此种催化剂中钯含量的报道不多,为此,建立光谱测定方法还是有必要的。一、标样的制备以Al_2O_3为基体,加入一定量的钯标液。在红外灯下烤干,捣细,在石英管内通氢气600℃还原1小时,磨均,配制一高含量标样。然后以Al_2O_3依次稀释配制含钯量0.003％至0.2％的一套标准试样。标样与碳粉以1:1混合。往碳粉中加入Co_2O_3,钴在碳粉中的含量为0.1％,以钴作内标元素。     

二阶标准加入法误差传递的Monte Carlo模拟

介绍二阶标准加入法的应用步骤,讨论影响分析结果准确度的各种因素。以一个模拟的两组分激发一发射荧光数据体系为例,采用Monte Carlo技术,模拟二阶标准加入法应用过程中标准加入次数、加入量、移液误差及测量误差对分析结果准确度的影响。所得结论可在实验设计及操作中作为参考。     

Determination of propranolol enantiomers in plasma and urine by spectrofluorimetry and second-order standard addition method

The determination of propranolol enantiomers in human plasma and urine by spectrofluorimetry and a second-order standard addition method is described. The methodology is based on chiral recognition of propranolol by formation of an inclusion complex with β-cyclodextrin, a chiral auxiliary, in the presence of 1-butanol. The adopted strategy combines the use of PARAFAC, for extraction of the pure analyte signal, with the standard addition method, for determinations in the presence of an individual matrix effect caused by the quenching action of the proteins present in the plasma and urine. A specific PARAFAC model was built for each sample, in triplicate, and the scores were related to (R)-propranolol mole fraction using a linear regression in the standard addition method. Using a propranolol with concentration of 260 ng mL⁻¹, good results were obtained for determinations in the mole fraction range from 50 to 80% of (R)-propranolol, providing absolute errors between 0.4 and 3.6% for plasma and between 0.9 and 6.0% for urine.     

NMR assay of ephedrine hydrochloride in tablets

A rapid NMR method is described for the determination of ephedrine hydrochloride. The relative standard deviations are 1.5% and 1.2% for the pure drug and tablets respectively. The results for synthetic mixtures and tablets are comparable to those obtained by the B.P. 1973 method. In addition, the NMR spectrum furnishes a specific means of identification of ephedrine.     

Sequential injection analysis of chloride and nitrate in waters with improved accuracy using potentiometric detection

Accurate simultaneous analysis of different anionic species using ion-selective electrodes (ISEs) can be achieved even for non-specific sensors by resorting to an ordinary least squares multiple regression in the vicinity of the predicted concentrations. In this work the potentialities of this approach are evidenced by the determination of nitrate and chloride in synthetic and real water samples in which chloride concentration was significantly higher than nitrate. An AgCl/Ag₂S electrode based on a homogeneous crystalline membrane together with a PVC electrode based on tert-octylammonium bromide dissolved in dibutylphthalate were used as potentiometric detectors for chloride and nitrate, respectively. For the implementation of the procedure, an automatic system based on sequential injection analysis was used. The results obtained by the standard addition method were biased for low concentrations of nitrate and were dependant on the relative proportion of NO₃⁻/Cl⁻. The results obtained by the proposed methodology for chloride determination were slightly better when compared to those obtained by the standard addition method. In relation to nitrate determination, the proposed methodology yielded values with a relative root mean square error of prediction (RRMSEP) of 2.8%, while for standard addition calibration, mean error values were approximately 12.1%.     

Discrimination of Pure and Mixture Agarwood Oils via Electronic Nose Coupled with k-NN kfold Classifier

Agarwood oils are extracted from low grade agarwood chips which are commonly processed via distillation. They can be obtained from various Aquilaria species such as A. malaccensis, A. hirta and A. crassna. This viscous oil is called as pure agarwood essential oil (100% of extracted material). Commonly, the oils are releasing long-lasting woody, warm and smoky scent due to slow release when applied to the skin. The blending of a small amount of this precious agarwood oil with other essential oils such as geranium, sandalwood, gurjum balsam, jasmine and Ylang ylang can give rich, complex and pleasant oils. Agarwood oil acts as a base note to fix the perfume odour comprising of middle and top notes. Currently, there is no scientific technique used to differentiate pure and mixture agarwood oils and usually, it is based on the different results and inconsistency from traders and buyers agreement. Thus, as part of our work on the authentication of agarwood oils from Malaysia, we propose a method to discriminate pure and mix agarwood oils via electronic nose (E-Nose) coupled with k-NN kfold classifier with accuracy percentage improvement from 90% to 100% accuracy compared to the standard manufacturer statistical tool Discriminant Factorial Analysis (DFA).     

内标法测定偏二甲肼中的杂质含量

偏二甲肼(Unsymmetrical D imethylhydrazine,UDMH)是液体火箭推进剂主体燃烧剂之一,它与硝基氧化剂等组成双组元液体推进剂作为火箭发动机的能量工质,被广泛应用于导弹、卫星及航天器的发射中。偏二甲肼中杂质含量水平对于保证火箭的顺利发射具有重要意义。在有关标准和技术规     

核磁共振法测定松香中树脂酸总量及枞酸与脱氢枞酸含量

本文用吡嗪作分子间内标，利用氢核磁共振（＾１Ｈ－ＮＭＲ）积分法对松香中枞酸，脱氢枞酸及树脂酸总量进行了测定，并对该方法的可靠性进行了研究和比较，结果令人满意。该法不仅可以克服松香中各异物体及同系物的干扰，而且不必用极难制备和保存的天然纯纵酸和脱氢枞酸作标样。     

Standard addition method applied to the urinary quantification of nicotine in the presence of cotinine and anabasine using surface enhanced Raman spectroscopy and multivariate curve resolution

In this work, urinary nicotine was determined in the presence of the metabolite cotinine and the alkaloid anabasine using surface enhanced Raman spectroscopy and colloidal gold as substrate. Spectra were decomposed using the multivariate curve resolution-alternating least squares method, and pure contributions were recovered. The standard addition method was applied by spiking urine samples with known amounts of the analyte and relative responses from curve resolution were employed to build the analytical curves. The use of multivariate curve resolution in conjunction with standard addition method showed to be an effective strategy that minimized the need for reagent and time-consuming procedures. The determination of the alkaloid nicotine was successfully accomplished at concentrations 0.10, 0.20 and 0.30 μg mL⁻¹ and total error values less than 10% were obtained.     

电感耦合等离子体原子发射光谱(ICP-AES)法测定镀锡钢板中的镀锡量

建立了电感耦合等离子体原子发射光谱(ICP-AES)法测定镀锡钢板中的镀锡量的方法。为避免复杂基体、溶样时间对测试结果产生干扰,采用标准加入法进行定量分析。通过实验,确定了溶样用盐酸的浓度、ICP仪器参数以及待测元素的分析线。考察了标准曲线的相关性、精密度和准确度等分析指标。结果表明,标准曲线成线性关系(R=0.998 8),检测结果的相对标准偏差仅为1.3%,与现有的国家标准分析方法——碘酸钾滴定法和X射线荧光光谱法进行对比实验,测量结果基本一致。     

凝胶渗透色谱用聚丙烯酸标样的制备

以二氧六环为良溶剂,石油醚为沉淀剂,通过等温沉淀分级,制得8种不同分子量的聚丙烯酸标样。 采用渐近校正法测定了它们的峰值分子量和分子量分布,建立了GPC校正曲线,并将其用于聚丙烯酸试样的测定。 结果表明,由渐进校正法测得的粘均分子量与粘度法测得的分子量之间的平均相对误差为7%,由渐进校正法测得的数均分子量与端基滴定法测得分子量之间的平均相对误差为9%。 将上述标样用于实际聚丙烯酸试样的测定,测得试样的粘均分子量与粘度法测定结果之间平均相对误差小于10%,优于以聚乙二醇为标样测定的平均相对误差（30%左右）。 本标样可用于具有与聚丙烯酸相似结构的阴离子聚电解质分子量分布的测定。