Calculation of Self-Attenuation Factors in Gamma-Ray Spectrometry for Samples of Arbitrary Shape

The distribution of photons detected in a spectrometer as a function of their path length in the sample can be approximated by a one-parametric family of functions. The members of the family, having different average path lengths, describe the transport of photons in samples of different shapes. The value of the parameter corresponding to the actual counting geometry is obtained from the measured average path of photons in the sample. The self-attenuation factor as a function of the attenuation coefficient is calculated as the Laplace transform of the member of the family, defined by the extracted value of the parameter.     

The Analysis of Environmental Samples by Mass Spectrometry

Mass spectral analysis was carried out on shellfish samples taken in the vicinity of the Arrow oil spill at Chedabucto Bay, Nova Scotia. Oil samples were also analyzed, samples being obtained from the tanker and also from the beach.

After extraction of the oil and shellfish samples, group separations were made into aliphatic, aromatic and oxygenated fractions, which were analyzed separately by mass spectrometry. The validity of the group separations was established, since, in the analysis of the so-called aliphatic fraction, no evidence of aromatics could be seen by mass spectrometry.

On the other hand, polycyclic hydrocarbons were found in some of the aromatic fractions. Identification was based upon standard mass spectrometric analysis already performed on known examples of the polycyclics.

It was concluded that the possibility of oil contamination can be confirmed by the mass spectrometric analysis of appropriate samples. It was also concluded that the so-called control samples should have been taken at a greater distance from the oil spill.     

Determination of Thallium In Solid Environmental Samples By Electrothermal Atomic Absorption Spectrometry

Abstract

A method for the determination of thallium in solid environmental samples is developed. After destruction of the sample, TI(III) is extracted from 0.5 M hydrobromic acid solution into diisopropyl-ether. the organic phase is evaporated and the residue taken up in a mixture of sulfuric and nitric acids. Measurements are carried out with an atomic absorption spectrometer with Zeeman background corrector. the accuracy of the method is tested by analysis of certified reference materials and the method is applied to fly ash and emitted particulate matter from a municipal refuse incinerator and to soil samples.     

Maintaining Accuracy in Gamma-Ray Spectrometry at High Count Rates

Gamma-ray spectrometry losses through pulse processing dead time and pile-up are best assayed with an external pulse technique. In this work, the virtual pulse generator technique as implemented commercially with the Westphal loss free counting (LFC) module is set up and tested with four high resolution gamma-ray spectrometers. Dual source calibration and decaying source techniques are used in the evaluation of the accuracy of the correction technique. Results demonstrate the reliability of the LFC with a standardized conventional pulse processing system. The accurate correction during high rate counting, including during rapid decay of short lived activities, has been the basis for highly precise determinations in reference materials studies.     

微波等离子体原子发射光谱新技术同时测定环境水样中多种元素

环境水样经不同酸消解后,利用微波等离子体原子发射光谱法(MP-AES)和多模式样品导入系统(MSIS)对环境水样中可蒸气发生元素(As,Hg,Sb和Se)及重金属元素(Cd,Cu,Cr,Ni,Pb,Ti,V和Zn)同时分析,分别根据溶液中元素信号强度变化和测定值与加标值差异,优化氢化物发生条件和考察测定的基体及谱线干扰影响.结果表明,在还原剂溶液(1.0％ NaBH4,m/V)和载流HCl(5％,V/V)的最佳实验浓度下,相比HC1消解,水样经HNO3消解可获得满意分析结果;环境标准样品中元素测定值与标准值一致,样品分析相对标准偏差在0.34％ ～ 3.2％范围内.高浓度的K,Ca,Na和Mg等元素对测定无明显影响,稀土元素和稀有元素对重金属光谱干扰严重,需选择合适谱线分析.本方法除对Hg和Se的检出限稍高外(6.5和37.1μg/L),其它目标元素检出限为1.6～9.8μg/L,能够满足地表水环境质量标准和生活饮用水卫生标准的质量控制要求.     

大气中气相和颗粒相三氟乙酸浓度测定

建立了我国大气中气相和颗粒相三氟乙酸(Trifluoroacetic acid,TFA)的采集和分析方法。采用环形扩散管-滤膜联用装置分离气相和颗粒相,利用环形扩散管的碱性涂层吸附气相TFA,石英滤膜吸附颗粒相物质。对气相和颗粒相样品分别处理,以2,4-二氟苯胺作为衍生剂,与TFA反应生成TFA的苯胺产物,采用GC/MS进行分析。本方法在0.31～4.91μg/L浓度范围内呈线性关系(R2=0.9991),检出限为66 ng/L。采样装置回收率为(101±3)%,当采样量为48 m3,TFA大气浓度检出限为31 pg/m3。于2012年4～10月在北京大学采样点采集大气,测得其中TFA总浓度在501～7447 pg/m3范围,TFA在气相中的浓度大于在颗粒相中的浓度,气固分配系数Kp随温度变化。     

氢化物发生—电感耦合等离子体原子发射光谱法测定环境样品中痕量铅

提出了以重铬酸钾－铁氰经钾为氧化剂的铅氢化物发生氧化还原体系。采用连续氢化物发生器，对电感耦合等离子体原子发射光谱法，测定痕量铅的条件进行了研究。选定条件下，以０２％硫氰酸钾－０．４５草酸为干扰抑制剂，测得铅的检出限为０．０９μｇ／Ｌ，相对标准偏差为０．４９％。对环境标准物质进行分析，结果令人满意。     

顺序注射蒸气发生非色散原子荧光光谱法测定环境样品中痕量硒

建立了双泵顺序注射与氢化物发生非色散原子荧光光谱法联用,测定环境样品中痕量硒的方法。线性范围为0．25～10μg/L;检出限为0．02μg／L;测定精度(RsD)为0．97％(2μg／L,n=11)。每小时可分析80(240次注射)个样品。环境水样的回收率为97％～107％;对国家标准参考物质(GBW07405和GBW07314)的测定结果同推荐值一致。     

Identification of Petroleum Products in Environmental Samples Using Gas Chromatography and Gas Chromatography–Mass Spectrometry

Typical analytical features of petroleum products in environmental samples were considered. Among them are typical shapes of chromatograms; peaks of n-alkanes; the ratio between n-alkanes with even and odd numbers of carbon atoms; peaks of biomarkers (isoprenanes, steranes, triterpanes, etc.); the predominance of methyl- and alkyl-substituted mono-, bi-, and polynuclear aromatic hydrocarbons over unsubstituted aromatic hydrocarbons; and other features. These features altogether enable reliable conclusions about the petroleum origin of the identified pollutants to be made.     

高效液相色谱-串联质谱法测定环境水样中多种杀菌剂残留量

建立了环境水样中多种杀菌剂残留量的高效液相串联质谱(LC-MS/MS)分析方法。通过氟吗啉和烯酰吗啉的光照实验,研究了其顺反异构体的转化规律,确定了它们的色谱行为。优化了固相萃取(SPE)过程参数,选择HLB为固相萃取柱,4 mL甲醇水(12:88,V/V)为淋洗液,3 mL甲醇为洗脱液。分析了环境水样中多种杀菌剂的基质效应影响,采用基质匹配曲线消除了基质效应。采用液相色谱分离,正离子多反应监测模式进行质谱分析。多种杀菌剂的方法定量限为0.003～0.03μg/L(环酰菌胺0.3μg/L)。在各自分析物的线性范围内,回收率为70.2%～108.9%,相对标准偏差均小于16.7%。本方法具有快速、准确、灵敏度高、选择性好等特点。在辽宁地区环境水样检测中,蒲河水检出嘧菌酯0.051μg/L、精甲霜灵0.217μg/L和烯酰吗啉0.05μg/L,浑河水检测出烯酰吗啉0.004μg/L。     

电感耦合等离子体-质谱联用及其在环境和生物样品中铂族金属分析的应用进展

本文简述了电感耦合等离子体-质谱联用(LCP-MS)技术和仪器的发展,分析了环境和生物样品中铂族金属分析的主要困难,综述了90年代以来国内外ICP-MS技术在环境和生物样品中铂族金属分析的最新进展,引用文献47篇.     

环境试样分析

本文是“分析试验室”定期评述中“环境试样分析”专题的第四篇评述。它叙述了１９９２年１月至１９９３年１２月期间我国有关环境试样分析的研究工作进展。内容包括概述、大气分析、水分析、沉积物分析、生物样品分析及有机物测定。共引用文献６７４篇。     

环境试样分析

本文是《分析试验室》的定期评述中“环境试样分析”的第５篇评论。它评论了从１９９４年１月至１９９５年１２月期间我国环境试样分析的进展，包括综述、大气分析、水分析、沉积物分析、生物样品分析和有机污染物分析引用参考文献４９４篇。     

环境试样分析

本文是《分析试验室》的定期评述中‘环境试样分析’的第６篇评论，它评论了从１９９６年１月至１９９７年１２月期间我国环境试样分析的进展，包括综述、大气分析、水分析、废水和沉积物分析、生物样品分析和有机污染物分析，引用了参考文献６２０篇。     

浊点萃取-石墨炉原子吸收光谱法测定环境样品中的痕量镉

研究了浊点萃取-石墨炉原子吸收光谱法(GFAAS)测定痕量镉的新方法,利用表面活性剂Triton X-100和络合剂1-(2-吡啶偶氮)-2-萘酚(PAN)对镉进行浊点萃取。详细探讨了影响浊点萃取及测定灵敏度的因素。优化条件为:0.25 mL 30%NaC l,pH 8.5,0.50 mL、4.0×10-4mol/L PAN,0.2 mL 1.0%TritonX-100。在最佳条件下,镉的富集倍率为50倍,检出限为5.9 ng/L,RSD为2.1%。该方法用于环境样中痕量镉的富集和测定,结果令人满意。     

气相色谱-串联质谱法同时快速检测环境水样中11种合成麝香

应用气相色谱-串联质谱法(GC-MS/MS)建立了环境水样中佳乐、吐纳、特拉斯、开许梅龙、萨利、粉檀、二甲苯、麝香酮、伞花、葵子、西藏11种典型的合成麝香(Synthetic Musks)的同时快速检测方法。采用Oasis HLB固相萃取柱、乙酸乙酯为洗脱液对水样进行预处理。在最优条件下,目标物线性范围均为0.05~10ng/L(R2为0.995~0.999),回收率为83.9%~112.7%,相对标准偏差(RSD)为3.5%~9.9%。该方法具有检测限低、回收率高等优点,经实际样品测试,可适用于环境水样中上述11种典型合成麝香的同时检测。     

浊点萃取-石墨炉原子吸收光谱法测定环境样品中的镉

建立了浊点萃取分离富集石墨炉原子吸收光谱法测定环境样品中痕量镉的方法.浊点萃取选择8-羟基喹啉为螯合剂,Triton X-100为表面活性剂.在pH 8～9、0.01%8-羟基喹啉和0.2%-Triton X-100、80 ℃水浴20 min的优化条件下,所建立方法的检出限为2.5 ng/L; 加标回收率为94.6%～106.2%; 对样品溶液进行富集的富集因子为17.利用该方法分别测定了2个实际水样和2个国家标准参考物质中的总镉含量,结果令人满意.     

超高效液相色谱-串联质谱法快速分析环境水样中的碘海醇和碘帕醇残留量

建立了超高效液相色谱-串联质谱(UPLC-MS/MS)法测定环境水样中碘代造影剂碘帕醇和碘海醇.样品加入等体积乙腈稀释后离心后,采用PHNOMON Kinetex F5柱(100 mm×3 mm,2.6 μm)进行分离,以0.1％甲酸水溶液-乙腈为流动相,梯度洗脱,在电喷雾离子源、正离子模式下,采用多反应检测模式检测,...