X射线荧光光谱法测定农田底泥中8种元素

建立X射线荧光光谱法测定农田底泥样品中砷、铬、铜、锰、镍、铅、锌、铁8种元素含量的分析方法.以塑料环粉末压片法制样,选用50种土壤、水系沉积物标准物质拟合校准曲线,探讨各元素的测定条件.当待测样品与建立校准曲线的标准样品粒径均小于75μm时,能够有效减少矿物效应和粒度效应的影响,从而提高检测准确度;各元素在各自的含量范...     

近红外光谱法快速测定肼-70纯度

利用重量法精确配制不同肼质量分数的肼-70样品集,采用偏最小二乘法建立了肼质量分数的近红外光谱模型,以快速测定肼-70的纯度。样品恒温时间为5 min,光谱最佳预处理方式:均值中心化,一阶导数,21点平滑,模型最佳主因子数为4。近红外光谱法与碘酸钾直接滴定法测定结果相比相对偏差绝对值小于0.13%,经t检验,两种方法测定结果无显著性差异。近红外光谱法快速、准确,可用于肼-70产品的质量控制。     

微波消解 电感耦合等离子体质谱（ICP-MS）法测定土壤改良剂矸石骨料中植物所缺必需微量元素

本方法通过微波消解方式及HF:HClO3:HNO3混酸体系,建立电感耦合等离子体质谱法(ICP-MS)测定土壤改良剂矸石骨料中植物所缺必需微量元素(Cu 、Co、Zn、Mn)的方法。采用钪(⁴⁵Sc)为内标元素和统一高盐基体的外标标准曲线进行信号漂移的抑制以及基体干扰的消除,同时选择丰度大的⁶³Cu、⁵⁹Co、⁶⁴Zn和⁵⁵Mn同位素元素进行测试,通过测定国家标准物质和国标方法对比的方式验证方法的准确性。Cu、Co、Zn和Mn在0.1-100纳克/毫升范围内,校准曲线的线性相关系数均大于0.9999,分析方法检出限均小于0.292微克/克。将方法用于实际样品分析,相对标准偏差(n=11)不高于2.92%,加标回收率在96%~103.57%范围内。     

波长色散X射线荧光光谱法测定钴精矿中钴、铜和锰

采用高纯氧化物经四硼酸锂和偏硼酸锂熔融制备人工标准样品,以氧化镱为内标,制作校准曲线,建立了波长色散型X射线荧光光谱法测定钴精矿中钴、铜、锰元素的分析方法.重点研究了混合熔剂、试样稀释比、氧化剂和内标选择、方法检出限、方法准确度和精密度等,结果表明,各元素校准曲线线性范围宽,相关系数均大于0.999,钴、铜、锰元素检出...     

X射线荧光光谱法测定铁矿石中SiO2含量的校准曲线的评估

<正>SiO₂是铁矿石主要杂质成分之一,是评价铁矿石品质的重要指标,常采用X射线荧光光谱法^[1]测定其含量。测定前,需要先用具有一定浓度水平范围的标准样品系列建立校准曲线,校准曲线性能检验不仅是方法确认和验证的重要内容,还是测量溯源的有效途径,获得满意测量结果的基础。大多数日常检测中,仅用校准曲线的相关系数作为曲线质量的评判准则是不够的,这是因为相关系数只能说明数据点是否近似在一条直线上,而不能评估校准曲线的精密度和准确度。     

波长色散X射线荧光光谱法测定钴精矿中钴、铜和锰含量

采用高纯氧化物经四硼酸锂和偏硼酸锂熔融制备人工标准样品,以氧化镱为内标,制作校准曲线,建立了波长色散型X射线荧光光谱法测定钴精矿中钴、铜、锰元素的分析方法。重点研究了混合熔剂、试样稀释比、氧化剂和内标选择、方法检出限、方法准确度和精密度等,结果表明,各元素校准曲线线性范围宽,相关系数均大于0.999, 钴、铜、锰元素检出限分别达到0.002%、0.001%和0.001%,测试准确度和精密度可靠,方法满足行业检测需求。     

双通道在线连续流动分析法同时测定环境水样中总磷和磷酸盐

准确测定环境水样中的总磷和磷酸盐含量,对于评价水体的环境污染程度和富营养化程度具有非常重要的意义。本文在对比已有国标分析方法的基础上,建立了连续流动分析法同时测定环境水样中总磷和磷酸盐的分析方法。样品和总磷、磷酸盐的试剂分别通过自动进样器和蠕动泵在线载入各自管路,再进入各自的化学分析模块进行化学反应,之后进入各自的比色计在波长为660nm条件下完成检测,全程在线自动分析,因此,可以实现一次进样就可以同时测定样品中总磷和磷酸盐含量,大大提高了分析效率。对消解试剂及浓度、加热温度、泵速等条件进行了最佳优化,保证了样品能消解完全且反应充分。将采集后的样品酸化处理后在10天内进行分析测定,避免了时间过长后水样变质对结果的影响。以空白介质溶液配制校准系列,使得校准系列与试样基体匹配,消除了基体效应干扰影响。结果表明：在最佳的实验条件下,校准曲线的线性相关性较好;总磷和磷酸盐测定结果的相对标准偏差(RSD)为1.05%～2.64%,精密度较好;总磷和磷酸盐方法检出限分别为0.010mg/L和0.022mg/L;经国家水样标准物质验证,方法相对误差(RE)均在±5%以内,测定值与标准值相吻合,方法准确度较好;应用本文方法对实际样品进行分析,并与传统国标方法进行比对,测定值的相对偏差(RD)均小于5%,更进一步验证了该分析方法准确可靠,能够满足大批量环境水样中总磷和磷酸盐的分析要求。     

气相分子吸收光谱法测定水中硝酸盐氮

硝酸盐氮是水环境质量重点监测项目之一,建立节省人力、高效快捷、抗干扰能力强的测试水中硝酸盐氮的分析方法十分必要。本文从载气类型、载气流量、定量方式、加热温度、载流液配比等方面系统的优化气相分子吸收光谱法测定水中硝酸盐氮的仪器条件。在优化的仪器条件下,工作曲线相关系数为0.9995;检出限为0.006 mg/L,测定下限为0.024 mg/L;标准物质测定的相对误差范围在0.0%~0.6%,实际样品测定的相对标准偏差范围在0.5%~5.5%;实际样品加标回收率范围在89.0%~102%。方法的检出限、精密度和准确度良好,适用于水质硝酸盐氮的测定。     

混合酸溶-电感耦合等离子体发射光谱(ICP-OES)法同时测定多金属矿石中铜铅锌钼

为解决多金属矿石的传统分析方法中样品前处理冗长复杂、Mo的线性范围窄、不能与Cu、Pb、Zn同时测定的缺点,通过考察溶样体系、仪器工作条件、干扰及消除,建立了电感耦合等离子体发射光谱(ICP-OES)同时测定Cu、Pb、Zn、Mo四种元素的方法。结果表明,方法测定范围较宽(0.001%～20.0%),各元素校准曲线线性相关系数均在0.999 5以上,检出限为5～9μg/g。用国家标准物质进行验证,方法精密度(RSD,n=12)为0.020%～5.0%,相对误差为-4.61%～4.17%,加标回收率为88.0%～108%。实际样品的测定结果与传统方法一致,方法适合大批量、多成分分析。     

氧弹分解-原子荧光法快速测定煤中汞

建立了氧弹分解-原子荧光法快速测定煤中Hg含量的方法。考察了吸收液种类、样品质量、吸收液体积、静置吸收时间对测定结果的影响,并对吸收反应机理进行了分析。结果表明,0.01 mol/L KMn O_4(3%H_2SO_4)溶液作为吸收剂时,对煤中Hg的吸收最好,回收率在96%~102%;随着样品质量的增加,回收率下降,0.2 g样品量最为适宜;5 m L吸收液、静置吸收10 min效果较好。校准曲线在0~2.0 ng/m L Hg范围线性良好,相关系数大于0.9995;方法检出限为7 ng/g。经t检验,氧弹分解-原子荧光法与直接测汞仪法无统计学意义上的差异,方法可用于煤中Hg含量的快速检测。     

Determination of hydrazine derivatives by flow-injection analysis with spectrophotometric detection

Flow-injection analysis for the determination of hydrazine derivatives based on their nucleophilic substitution reaction with 4-chloro-5,7-dinitrobenzofurazan in aqueous medium, and spectrophotometric detection has been described. The calibration graphs were linear in the range from 0.15 to 4.0 mug ml(-1) of hydrazine derivatives, with sampling rates of up to 28-32 samples h(-1). Interferences from amino compounds, benzoic acids, aliphatic amines and ammonia have been evaluated. The procedure has been applied to the determination of hydrazine derivatives in serum, urine, appressin drugs and artificial mixtures.     

A novel hydrazine electrochemical sensor based on the high specific surface area graphene

An ultrasensitive platform is presented for the determination of hydrazine by combining the high specific surface area and higher electrical conductivity of poly(sodium styrenesulfonate) (PSS) graphene nanocomposite film with amperometric detection. The PSS-graphene were synthesized by the Hummers method and used to modify a glassy carbon electrode. The material was characterized by scanning electron microscopy and is found to be suitable for sensing hydrazine. The overpotential of hydrazine on the modified electrode is 0.31 V which is lower than in many electrochemical sensors. The calibration curve for hydrazine is linear in the range from 3.0 to 300 µmol L^?1, and the detection limit is as low as 1 µmol L^?1. This is the first report in which such a high sensitivity and low limit of detection has been achieved. It is concluded that PSS graphene represents an efficient electron mediator for sensing hydrazine.     

Sensitive and Rapid Flow Injection Amperometric Hydrazine Sensor using an Electrodeposited Gold Nanoparticle Graphite Pencil Electrode

A gold (Au) nanoparticle-modified graphite pencil electrode was prepared by an electrodeposition procedure for the sensitive and rapid flow injection amperometric determination of hydrazine (N₂H₄). The electrodeposited Au nanoparticles on the pretreated graphite pencil electrode surface were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction spectroscopy, and electrochemical impedance spectroscopy. Cyclic voltammograms showed that the Au nanoparticle-modified pretreated graphite pencil electrode exhibits excellent electrocatalytic activity toward oxidation of hydrazine because the highly irreversibly and broadly observed oxidation peak at +600?mV at the pretreated graphite pencil electrode shifted to ?167?mV at the Au nanoparticle pretreated graphite pencil electrode; in addition, a significant enhancement in the oxidation peak current was obtained. Thus, the flow-injection (FI) amperometric hydrazine sensor was constructed based on its electrocatalytic oxidation at the Au nanoparticle-modified pretreated graphite pencil electrode. The Au nanoparticle-modified pretreated graphite pencil electrode exhibits a linear calibration curve between the flow injection amperometric current and hydrazine concentration within the concentration range from 0.01 to 100?µM with a detection limit of 0.002?µM. The flow injection amperometric sensor has been successfully used for the determination of N₂H₄ in water samples with good accuracy and precision.     

Indirect simultaneous kinetic determination of semicarbazide and hydrazine in micellar media by H-point standard addition method

H-point standard addition method (HPSAM) is suggested as a simple and selective method for the determination of semicarbazide and hydrazine. The reduction of Cu²⁺ to Cu⁺ by semicarbazide and hydrazine in the presence of neocuproine (Nc) and the subsequent complex formation between Cu⁺ and Nc produced a sensitive spectrophotometric method for indirect determination of semicarbazide and hydrazine. The difference in the rate of reduction of Cu²⁺ with semicarbazide and hydrazine in cationic micellar media is the basis of this method. Semicarbazide can be determined in the range of 0.5-3.75 μg ml⁻¹ with satisfactory accuracy and precision in the presence of excess hydrazine. The proposed method was successfully applied to the simultaneous determination of semicarbazide (0.5-3.75 μg ml⁻¹) and hydrazine (0.5-5 μg ml⁻¹) and also to the selective determination of semicarbazide in the presence of hydrazine in several synthetic mixtures containing different concentration ratios of semicarbazide and hydrazine.     

离子色谱法检验液体炸药爆炸尘土中的肼离子

建立了离子色谱检测液体炸药爆炸尘土中肼离子的方法。用去离子水超声提取尘土样品中的肼离子,离心后取上清液并将其分别过OnGuardⅡ RP小柱和0.22 μm过滤膜,经IonPac CS-12A阴离子色谱柱(250 mm×4 mm)分离,采用5 mmol/L甲基磺酸等度淋洗,0.1 mol/L NaOH溶液柱后加碱,金电极安培检测器检测。结果表明,肼离子质量浓度在0.02~2.0 mg/L范围内的线性关系良好(相关系数r²=0.9997)。以信噪比(S/N)为3确定方法检出限为5.0 μg/L, S/N为10确定方法定量限为16.6 μg/L。方法回收率在95.4%~99.1%之间,相对标准偏差(RSD, n=5)在2.1%~3.3%之间。应用该方法检测液体炸药爆炸尘土中肼离子的含量为10.3 mg/kg。该方法操作简便,结果准确,适用于液体炸药爆炸尘土中肼离子的定量检测,满足刑事物证鉴定工作的需要。     

Determination of analytical limits in solid sampling ETAAS: a new approach towards the characterization of analytical quality in rapid methods

In the present study the lower analytical limits of solid sampling electrothermal atomization atomic absorption spectrometry (SS-ETAAS) were characterized by means of blank measurements and – for the first time – by means of the calibration curve method, where a calibration near the range of these limits (limit of decision, detection and quantification) was performed. The limit of decision as derived from blank measurements was calculated according to the 3σ-criterion to be 0.003 and 0.019 ng for Cd and Pb, respectively. For Pb and Cd a roughly threefold increase of these limits was observed when the calibration method according to DIN 32 645 was applied. When solid reference material was used, only a slight increase could be observed. The analytical limits were 2 to 20 times lower than reported for sample decomposition methods. The blank measurement and conventional calibration curve method, however, do not account for factors relating to solid sampling such as sample mass and matrix. Therefore, the calibration curve model was applied to data derived from comparisons between direct solid sampling ETAAS and a compound reference method (ETAAS following sample homogenization and digestion). The observed analytical limits were not found to be substantially increased if enough samples with low element contents were available for calibration. Coupling of the calibration curve model with the comparison of methods included real test samples and thus the relevant maximum sample mass and analyte content in the range of the lower analytical limits. As validation procedures frequently include comparisons of methods, the present approach might prove to be of some general interest for the characterization of analytical quality in rapid methods.     

Flow injection determination of hydrazine with fluorimetric detection

A spectrophotometric flow injection system is described for the determination of hydrazine, involving oxidation of hydrazine by thallium(III) with concomitant formation of thallium(I). The optimum analytical conditions have been established. The linear range for hydrazine is 25-500 ng ml(-1) with a detection limit of 20 ng ml(-1). The sampling frequency is 40+/-5 samples h(-1). The relative standard deviation for 100, 250 and 500 ng ml(-1) is 3.5, 2.6 and 1.8%, respectively. The method has been applied to the determination of hydrazine in water.     

Determination of analytical limits in solid sampling ETAAS: a new approach towards the characterization of analytical quality in rapid methods

In the present study the lower analytical limits of solid sampling electrothermal atomization atomic absorption spectrometry (SS-ETAAS) were characterized by means of blank measurements and--for the first time--by means of the calibration curve method, where a calibration near the range of these limits (limit of decision, detection and quantification) was performed. The limit of decision as derived from blank measurements was calculated according to the 3sigma-criterion to be 0.003 and 0.019 ng for Cd and Pb, respectively. For Pb and Cd a roughly three-fold increase of these limits was observed when the calibration method according to DIN 32 645 was applied. When solid reference material was used, only a slight increase could be observed. The analytical limits were 2 to 20 times lower than reported for sample decomposition methods. The blank measurement and conventional calibration curve method, however, do not account for factors relating to solid sampling such as sample mass and matrix. Therefore, the calibration curve model was applied to data derived from comparisons between direct solid sampling ETAAS and a compound reference method (ETAAS following sample homogenization and digestion). The observed analytical limits were not found to be substantially increased if enough samples with low element contents were available for calibration. Coupling of the calibration curve model with the comparison of methods included real test samples and thus the relevant maximum sample mass and analyte content in the range of the lower analytical limits. As validation procedures frequently include comparisons of methods, the present approach might prove to be of some general interest for the characterization of analytical quality in rapid methods.     

粉末压片-X射线荧光光谱法测定富硅土壤和沉积物样品中的5种重金属元素

X射线荧光光谱法测定土壤和沉积物中的重金属具有简便、快速、准确等优点,但现有的环境行业标准方法不适用于SiO2含量大于80%的土壤和沉积物。为提高X射线荧光光谱法测定土壤和沉积物中的重金属在环境监测领域中的适用性,建立基于粉末压片-X射线荧光光谱法测定富硅土壤和沉积物中重金属的分析方法。通过选取富硅的土壤和沉积物标准物质提高校准曲线的测量范围以及优化各元素的测量条件,探讨基体效应和谱线重叠干扰、研究压片制样的最佳压力等途径,测定富硅土壤和沉积物中的Pb、Cr、Cu、Ni、Zn。结果表明在已优化的测定条件下,通过延长校准曲线的测量上限,保证待测元素含量在校准曲线范围内,同时采用经验系数法和康普顿散射内标法校正基体效应,可进一步提高方法的准确度和精密度。方法比对结果显示该方法的测定结果与原子吸收光谱法的测定结果无显著性差异。选用2种不同的富硅标准物质进一步验证方法的精密度和准确度,Pb、Cr、Cu、Ni、Zn的测定结果与标准物质认定值的对数误差为0.002~0.08,相对标准偏差为1.0%~4.6%。该方法的精密度和正确度满足土壤和水系沉积物环境监测分析的技术要求,具有良好的应用前景。     

Determination of captopril in pharmaceutical preparation and biological fluids using two- and three-way chemometrics methods

Spectrophotometric method has been developed for the direct quantitative determination of captopril in pharmaceuticalpreparation and biological fluids(human plasma and urine)samples.The method was accomplished based on parallel factoranalysis(PARAFAC)and partial least squares(PLS).The study was carried out in the pH range from 2.0 to 12.8 and with aconcentration from 0.70 to 61.50 μg mL~(-1)of captopril.Multivariate calibration models such as PLS at various pH and PARAFACwere elaborated from ultraviolet spectra deconvolution and captopril determination.The best models for this system were obtainedwith PARAFAC and PLS at pH 2.0.The applications of the method for determination of real samples were evaluated by analysis ofcaptopril in pharmaceutical preparations and biological fluids with satisfactory results.The accuracy of the method,evaluatedthrough the RMSEP,was 0.5801 for captopril with best calibration curve by PARAFAC and 0.6168 for captopril with PLS at pH 2.0model.