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Accurate and precise determination of lead isotope composition in selected geochemical reference materials 被引量:2
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作者 Guangliang Wu Jian-Ming Zhu +3 位作者 Decan Tan Guilin Han Lixing Zhang Kun Ren 《Acta Geochimica》 EI CAS CSCD 2017年第3期421-425,共5页
Lead(Pb)isotopes have been extensively employed in tracing sources of Pb and its transport pathways through the environment.However,Pb isotopic ratios in related geochemical reference materials are scarce.Here,we repo... Lead(Pb)isotopes have been extensively employed in tracing sources of Pb and its transport pathways through the environment.However,Pb isotopic ratios in related geochemical reference materials are scarce.Here,we report high-precision Pb isotopic ratios measured by Nu Plasma II MC-ICP-MS using calibrated ^(205)Tl/^(203)Tl=2.38865(NIST SRM 997)for mass discrimination correction.The long-term external precision(2SD)for NISTSRM 981 of Pb,BCR-2,and BHVO-2 are 0.31‰(n=105),0.42‰(n=11),and 0.25‰(n=5)for ^(208)Pb/ ^(206)Pb and 0.16‰,0.53‰,and 0.07‰for ^(206)Pb/ ^(207)Pb,both respectively,and their Pb isotopic ratios are in excellent agreement with the recommended values.Using this method,we report for the first time Pb isotopic compositions in shale SGR-1b(USGS);coal CLB-1(USGS);stream sediments GSD-17,-21,and-23(IGGE);soils GSS-12,-13,-14,-15,and-16(IGGE);plants GSV-1,-2,and-3(IGGE);and human hair GSH-1(IGGE). 展开更多
关键词 Lead isotopes Geochemical reference materials MC-ICP-MS
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REFERENCE MATERIALS 被引量:1
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《China's Tibet》 2002年第5期11-11,共1页
Potala PalaceConstruction of the Potala Palace began in the mid-7th century for the Tubo King Songtsan Gambo to greet his Han wife, Princess Wencheng. It comprised 999 rooms then, plus one built atop the Red Hill, whi... Potala PalaceConstruction of the Potala Palace began in the mid-7th century for the Tubo King Songtsan Gambo to greet his Han wife, Princess Wencheng. It comprised 999 rooms then, plus one built atop the Red Hill, which, said to have 1,000 rooms, was later destroyed by thunderbolts and wars. What we see today is a structure built during the 17th century.In the mid-17th century, the White House was added to the Potala Palace, which spread along the Red Hill in Lhasa.The palace is a structure of clay, wood and stone. The palace was the residence of the Dalai Lama of various generations. Beginning with the period of the 5th Dalai Lama, major religious and political ceremonies were held there.The palace covers a total area of 360,000 square meters, with major building rising 117 meters high in 13 floors, and extends some 360 meters from east to west.From 1989 to 1994, the State earmarked some 55 million Yuan and large quantities of gold and silver to repair the palace.In December 1994, the palace found its 展开更多
关键词 reference materials
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The Role of the American Oil Chemists’Society in World Trade——Quality Assurance Testing,Certified Reference Materials,and International Liaison Activities
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作者 Scott BLOOMER 《粮油食品科技》 2022年第1期73-78,共6页
The American Oil Chemists’ Society(AOCS) is a volunteer-led association. AOCS develops and publishes methods of analysis for fats, oils, proteins, surfactants, and related materials according to accepted internationa... The American Oil Chemists’ Society(AOCS) is a volunteer-led association. AOCS develops and publishes methods of analysis for fats, oils, proteins, surfactants, and related materials according to accepted international standards to ensure equitable trade practices on a global scale. AOCS Official Method development has been going on for over a hundred years. The founding vision of AOCS in 1909 was "an organization designed for the development and advancement of analytical methods for cottonseed products." AOCS Official Methods are essential to world trade and are used to confirm the value of billions of pounds of oilseed-based commodities and finished products each year. In addition, AOCS conducts proficiency testing, provides certified reference materials, and collaborates with other standards developers including the International Organization for Standardization(ISO) and the Codex Alimentarius Commission. AOCS serves as a professional scientific membership organization providing current and emerging information as well as disseminating research results in oils, fats, lipids, proteins, surfactants, and related materials. Several avenues are used, especially meetings, publications, interest groups, networking opportunities, and web presence. Many scientists, experts, and others engaged in working in these fields find their professional "home" in AOCS. The AOCS Technical Leadership Committee comprises some of the most experienced AOCS members and scientists. The AOCS Technical Services department staff relies on this committee for guidance on scientific matters and for advice in prioritizing the opportunities facing AOCS. 展开更多
关键词 analytical methods proficiency testing genetic modification reference materials oilseed meal cereals and pulses fats and oils codex alimentarius
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148 Reference Materials
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《China Standardization》 2009年第5期63-68,共6页
关键词 CRM reference materials DESIGN
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45 Reference Materials
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《China Standardization》 2008年第4期51-52,共2页
关键词 CRM reference materials
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Titanium Isotope Analysis of Igneous Reference Materials using a Double-spike MC-ICP-MS Method
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作者 LI Jin TANG Suohan +2 位作者 ZHU Xiangkun MA Jianxiong ZHAO Xinmiao 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2022年第2期517-524,共8页
Ti separation was achieved by ion-exchange chromatography using Bio-Rad AG 1-X8 anion-exchange and DGA resins.For high-Fe/Ti and high-Mg/Ti igneous samples,a three-column procedure was required,whereas a two-column pr... Ti separation was achieved by ion-exchange chromatography using Bio-Rad AG 1-X8 anion-exchange and DGA resins.For high-Fe/Ti and high-Mg/Ti igneous samples,a three-column procedure was required,whereas a two-column procedure was used for low-Fe/Ti and low-Mg/Ti igneous samples.The Ti isotopes were analysed by MC-ICP-MS,and instrumental mass bias was corrected using a ^(47)Ti-^(49)Ti double-spike technique.The ^(47)Ti-^(49)Ti double-spike and SRM 3162a were calibrated using SRM 979-Cr,certificated value ^(53)Cr/^(52)Crt rue=0.11339.Isobaric interference was evaluated by analysing Alfa-Ti doped with Na,Mg,Ca,and Mo,and results indicate that high concentrations of Na and Mg have no significant effect on Ti isotope analyses;however,Ca and Mo interferences lead to erroneousδ^(49/47)Ti values when Ca/Ti and Mo/Ti ratios exceed 0.01 and 0.1,respectively.Titanium isotopic compositions were determined for 12 igneous reference materials,BCR-2,BHVO-2,GBW07105,AGV-1,AGV-2,W-2,GBW07123,GBW07126,GBW07127,GBW07101,JP-1,and DTS-2b.Samples yieldδ^(49/47)Ti(‰)of−0.035±0.022,−0.038±0.031,0.031±0.022,0.059±0.038,0.044±0.037,0.000±0.015,0.154±0.044,−0.044±0.018,0.010±0.022,0.064±0.043,0.169±0.034,and−0.047±0.025(relative to OL-Ti,±2SD),respectively;of which isotopic compositions of DTS-2b,JP-1,GBW07101,GBW07105,GBW07123,GBW07126,and GBW07127 are reported for the first time.Standard Alfa-Ti was analysed repeatedly over a ten-month period,indicating a reproducibility of±0.047(2SD)forδ^(49/47)Ti,similar to the precisions obtained for geochemical reference materials. 展开更多
关键词 Ti isotope double-spike mass bias correction MC-ICP-MS reference material
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Scanning proton microprobe microanalysis for the assessmentof homogeneity of IAEA urban dust reference materials
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作者 Zhang Yuan-xun Gu Ying-mei +1 位作者 Zhu Ji-fang Zhu Jie-qing 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 1998年第3期9-13,共5页
In order to develop new reference materials for microanalytical nuclear techniques, scanning proton microprobe (SPM) technique was used to determine homogeneity level within 100×200 μm 2 micro area on the small ... In order to develop new reference materials for microanalytical nuclear techniques, scanning proton microprobe (SPM) technique was used to determine homogeneity level within 100×200 μm 2 micro area on the small pieces of IAEA urban dust reference materials. The experimental methods were described in detail. The results show that IAEA 396A/M Vienna urban dust is homogeneous enough for small sample analysis of standard reference material (SRM). 展开更多
关键词 standard reference material (SRM) scanning proton microprobe urban dust.
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Development of a Certified Reference Material from Caffeine Solution for Assuring the Quality of Food and Drug Measurements
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作者 Adel B. Shehata Abdulrahman R. AlAskar +3 位作者 Mohammed A. AlRasheed Abdulrahman M. AlZahrany Fahd A. AlKharraa Sowailem A. AlSowailem 《Green and Sustainable Chemistry》 2023年第3期216-236,共21页
Caffeine intake by pregnant women, adults and children can be harmful to the health of all particularly fetuses if the intake exceeds the permissible limits. Therefore, it is of fundamental importance to measure its c... Caffeine intake by pregnant women, adults and children can be harmful to the health of all particularly fetuses if the intake exceeds the permissible limits. Therefore, it is of fundamental importance to measure its concentration accurately using certified reference materials (CRMs). In the literature, no scientific details are published about the certification of caffeine standard solutions, and therefore, the present article covers this gap. A batch of caffeine solution was prepared in concentration of 1000 mg/kg and bottled. Homogeneity and stability of the candidate reference material were assessed by HPLC-UV and the results showed that the material is homogenous and stable enough. Characterization of the caffeine reference material was performed by HPLC-UV, LC-MS/MS and UV-VIS-NIR spectrophotometer in three different days and the characterization uncertainty was estimated in accordance with the requirements of ISO GUM. The certified value (999.86 ± 8.57 mg/kg) was derived as a weighted mean from the gravimetry and the three characterization methods and the certified uncertainty was calculated according to ISO Guide 35. The produced CRM is of strong interest to the food and drug analytical laboratories for the validity and credibility of their caffeine measurement results. 展开更多
关键词 CAFFEINE reference Material HOMOGENEITY Stability Characterization CERTIFICATION
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Certification of a Multicomponent Reference Material from Natural Gas Mixture by Gravimetry and Dual GC-FID/TCD System
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作者 Adel Bassuoni Shehata Abdulrahman Rashed AlAskar +1 位作者 Najjy Hamad AlYami Abdullah Suleiman AlOwaysi 《Green and Sustainable Chemistry》 2023年第4期269-290,共22页
Natural gas (NG) is one of the most important sources of energy for industrial and domestic consumption in the present era because it is cheap and free from sulfur impurities. Therefore, accurate and precise measureme... Natural gas (NG) is one of the most important sources of energy for industrial and domestic consumption in the present era because it is cheap and free from sulfur impurities. Therefore, accurate and precise measurement of its composition is of fundamental importance for trade reasons. To improve the quality of NG gas measurements, certified reference materials (CRMs) should be used for calibration of measuring equipment in order to ensure the traceability of the measurement results to the SI units. For the traceability purpose, a multicomponent natural gas mixture was prepared gravimetrically as a reference material according to ISO 6142 from pure helium, hydrogen, n-pentane, i-pentane, n-butane, i-butane, propane, ethane, hexane, methane and nitrogen. The preparation was done in two dilution steps in 5 L aluminum cylinders. The calculated mole fractions and associated uncertainties of natural gas components were verified by a dual GC-FID/TCD system in accordance with ISO 6143 calibrated by a series of primary gas mixtures (CRMs) produced by an NMI. The results obtained by gravimetry and by GC measurements have been checked for compatibility as required by ISO 6142 and were found in very good agreement. Details of the preparation and calculation of the mole fractions and uncertainties of all gas components are explained in this article. 展开更多
关键词 Pure Gases GRAVIMETRY reference Material Stability GC Verification Uncertainty
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Development of a Certified Reference Material from Caffeine Solution for Assuring the Quality of Food and Drug Measurements
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作者 Adel B. Shehata Abdulrahman R. AlAskar +3 位作者 Mohammed A. AlRasheed Abdulrahman M. AlZahrany Fahd A. AlKharraa Sowailem A. AlSowailem 《Case Reports in Clinical Medicine》 2023年第3期216-236,共21页
Caffeine intake by pregnant women, adults and children can be harmful to the health of all particularly fetuses if the intake exceeds the permissible limits. Therefore, it is of fundamental importance to measure its c... Caffeine intake by pregnant women, adults and children can be harmful to the health of all particularly fetuses if the intake exceeds the permissible limits. Therefore, it is of fundamental importance to measure its concentration accurately using certified reference materials (CRMs). In the literature, no scientific details are published about the certification of caffeine standard solutions, and therefore, the present article covers this gap. A batch of caffeine solution was prepared in concentration of 1000 mg/kg and bottled. Homogeneity and stability of the candidate reference material were assessed by HPLC-UV and the results showed that the material is homogenous and stable enough. Characterization of the caffeine reference material was performed by HPLC-UV, LC-MS/MS and UV-VIS-NIR spectrophotometer in three different days and the characterization uncertainty was estimated in accordance with the requirements of ISO GUM. The certified value (999.86 ± 8.57 mg/kg) was derived as a weighted mean from the gravimetry and the three characterization methods and the certified uncertainty was calculated according to ISO Guide 35. The produced CRM is of strong interest to the food and drug analytical laboratories for the validity and credibility of their caffeine measurement results. 展开更多
关键词 CAFFEINE reference Material HOMOGENEITY Stability Characterization CERTIFICATION
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Precise and accurate Ga isotope ratio measurements of geological samples by multi-collector inductively coupled plasma mass spectrometry
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作者 Yuxu Zhang Pan Qiao +2 位作者 Chuanwei Zhu Haifeng Fan Hanjie Wen 《Acta Geochimica》 EI CAS CSCD 2024年第6期1054-1064,共11页
Gallium isotope is a potential geochemical tool for understanding planetary processes,environmental pollution,and ore deposit formation.The reported Ga isotope compositions(δ^(71)Ga NIST994 values)of some internation... Gallium isotope is a potential geochemical tool for understanding planetary processes,environmental pollution,and ore deposit formation.The reported Ga isotope compositions(δ^(71)Ga NIST994 values)of some international geological standards,such as BCR-2 and BHVO-2 basalts,exhibit inconsistencies between diff erent laboratories.During mass spectrometry analysis,we found thatδ^(71)Ga NIST994 values of geological standards with or without the correction of the interference of^(138)Ba^(2+)(mass/charge ratio=69)on 69 Ga show signifi cant isotope off sets,and thus effi cient separation of Ba and correcting the interference of^(138)Ba^(2+)are both crucial to obtain accurateδ^(71)Ga values.By comparingδ^(71)Ga NIST994 values(relative to NIST SRM 994 Ga)of the same geostandards from diff erent laboratories,we suggest that the isotopic heterogeneity from NIST SRM 994 Ga is one of the key reasons for the inconsistencies inδ^(71)Ga NIST994 values of BCR-2 and BHVO-2.To facilitate inter-laboratory comparisons,we measured the Ga isotopic compositions of 11 geological reference materials(including Pb-Zn ore,bauxite,igneous rocks,and loess)and two Ga solution standards(NIST SRM 3119a and Alfa Aesar).Theδ^(71)Ga NIST994 andδ^(71)Ga IPGP values of these reference materials vary from 1.12‰to 2.63‰and−0.13‰to 1.38‰,respectively,and can be used to evaluate the precision and accuracy of Ga isotope data from diff erent laboratories. 展开更多
关键词 Ga isotopes MC-ICP-MS reference materials Chemical purification Ba interference
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Determination of Hf–Sr–Nd isotopic ratios by MC-ICP-MS using rapid acid digestion after flux-free fusion in geological materials 被引量:4
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作者 Zhian Bao Chunlei Zong +3 位作者 Linru Fang Honglin Yuan Kaiyun Chen Mengning Dai 《Acta Geochimica》 EI CAS CSCD 2018年第2期244-256,共13页
In this study, we established a rapid acid digestion for determining Hf-Sr-Nd isotopic ratios of geological samples by using MC-ICP-MS. Conditions of 1600 ℃ for 1 min and 1400 ℃ for 1 min were adopted for fusing int... In this study, we established a rapid acid digestion for determining Hf-Sr-Nd isotopic ratios of geological samples by using MC-ICP-MS. Conditions of 1600 ℃ for 1 min and 1400 ℃ for 1 min were adopted for fusing intrusive rocks and extrusive rocks, respectively. The rapid acid digestion technique is superior in digestion time compared with high-pressure PTFE bomb method. The procedural blanks of the method were also lower than that flux fusion. Replicate analyses of international certified reference materials (CRMs) indicate that isotopic ratios of ^176Hf/^177Hf, ^87Sr/^86Sr and 143Nd/144Nd agree well with previously published data. The external reproducibility (2SD, n = 5) of ten CRMs are ±0.000030 for ^87Sr/^86Sr, ± 0.000030 for ^143Nd/^144Nd, and ±0.000018 for ^176Hf/^177Hf. 展开更多
关键词 Certified reference material Flux-free fusion Hf-Sr-Nd isotopic ratio Procedural blank Rapid acid digestion
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Preparation and Certification of a New Salvianolic Acid A Reference Material for Food and Drug Research 被引量:1
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作者 Dezhi Yang Bin Su +5 位作者 Yancai Bi Li Zhang Baoxi Zhang Junke Song Yang Lu Guanhua Du 《Natural Products and Bioprospecting》 CAS 2020年第2期67-75,共9页
Salvianolic acid A(Sal A),a water-soluble ingredient in Danshen,has various biological activities.Sal A and its impurities have similar physical and chemical properties,as well as strong reducibility;therefore,they ar... Salvianolic acid A(Sal A),a water-soluble ingredient in Danshen,has various biological activities.Sal A and its impurities have similar physical and chemical properties,as well as strong reducibility;therefore,they are difficult to prepare and purify.In this study,high-purity Sal A was obtained by purification of sephadex chromatography and preparative chromatography.Furthermore,HPLC-DAD tandem ECD and HPLC-DAD tandem MS methods were used for non-volatile organic impurity analysis,ICP-MS method was used for non-volatile inorganic impurities and mass balance method and quantitative nuclear magnetic resonance were employed to certify the product.The structures of Sal A and its relative impurities were validated by nuclear magnetic resonance spectroscopy and mass spectrometry,and their contents were quantified as well.Following the principles of ISO Guides 34:2009 and 35:2005,a Sal A reference material was certified,covering homogeneity studies,stability studies,characterization,and uncertainty estimations. 展开更多
关键词 Certified reference material Salvianolic acid A Mass balance method qNMR High resolution mass spectrum
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Preparation of bovine liver candidate reference material
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作者 Zhang Yuan xun, Qian Yin e, Li De yi, Wang Yin song, Wang Xue peng Shanghai Institute of Nuclear Research, Chinese Academy of Sciences, Shanghai 201800, China 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 1998年第4期83-85,共3页
The bovine liver candidate reference material specially for micro analytical techniques was prepared. The preparation process including material collection, dried, pulverize, sieve, homogenization and preliminary tes... The bovine liver candidate reference material specially for micro analytical techniques was prepared. The preparation process including material collection, dried, pulverize, sieve, homogenization and preliminary test was described in detail. The more effective grinding methods were established to achieve the median particle size of 22μm. 展开更多
关键词 standard reference material bovine liver quality assurance.
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Determination of CeO_2 , Dy_2O_3, CuO and PbO in Yttrium Oxide Reference Material by Isotope Dilution Spark Source Mass Spectrometry
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作者 马树钦 陈瑾芳 《Rare Metals》 SCIE EI CAS CSCD 1992年第1期47-51,共5页
This paper describes the quantitative determination of rare-earth elements cerium, dysprosium and non-rare-earth element copper, lead and the homogeneity examination of these four elements in yttrium oxide reference m... This paper describes the quantitative determination of rare-earth elements cerium, dysprosium and non-rare-earth element copper, lead and the homogeneity examination of these four elements in yttrium oxide reference material by isotope dilution spark source mass spectrometry (ID-SSMS). The sensitivity of the meth- od is l0^(-5)~10^(-7%). The precision is better than 6%. The accuracy is better than 5%. The interferences of the spectra and the optimum amount of the spike added to the sample are discussed. The choice of the conducting material for the sample electrodes is studied. 展开更多
关键词 Isotope dilution Spark source mass spectrometry Y_2O_3 reference material
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Development of a certified reference material for visual inspection of unsound maize kernels
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作者 Zhang Huijie Li Jingmei +9 位作者 Wu Li Li Weixi Sun Lijuan Zhang Yan Zhao Hongxiang Hu Xuexu Jin Longguo Du Wenming Wang Bujun Fu Jindong 《China Standardization》 2022年第6期63-68,共6页
Maize unsound kernel content is one of the limited items in maize trade, and generally determined by sensory detection. A certified reference material(CRM) for visual inspection of maize unsound kernels was developed ... Maize unsound kernel content is one of the limited items in maize trade, and generally determined by sensory detection. A certified reference material(CRM) for visual inspection of maize unsound kernels was developed according to a national standard of China, GB 1353-2018, and five items, such as insect-damaged kernels, spotted kernels, broken kernels, sprouted kernels and moldy kernels, were included. Unsound maize kernels were collected from fields or prepared in a laboratory, then screened, and ten kernels demonstrating varying levels of unsoundness or damage for each item were embedded in epoxy resin. The CRM showed excellent homogeneity and stability, which was stable for 14 days at the temperature from-20℃ to 45℃ and for at least 18 months at room temperature out of direct sunlight and strong light. Co-laboratory confirmation showed the CRM conformed to the morphological characteristics described in GB 1353-2018. The research filled the gap of unsound maize kernel CRM in maize detection. 展开更多
关键词 maize unsound kernels certified reference material(CRM) visual inspection
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Preparation of Reference Material for Proficiency Test for Enumeration of Coliforms in Cheese Matrix
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作者 Marcelo Luiz Lima Brandao Carla de Oliveira Rosas +6 位作者 Silvia Maria Lopes Bricio Valeria de Mello Medeiros Juliana de Castro Beltrao da Costa Rodrigo Rollin Pinheiro Paola Cardarelli-Leite Marcus Henrique Campino de La Cruz Armi Wanderley da Nobrega 《Detection》 2013年第1期7-12,共6页
It is widely accepted that quantitative reference materials (RM), are indispensable tools for verification of the precision and accuracy of analytical measurements. The RM can be used by food microbiology laboratories... It is widely accepted that quantitative reference materials (RM), are indispensable tools for verification of the precision and accuracy of analytical measurements. The RM can be used by food microbiology laboratories, as part of their quality assurance programmes, to achieve their quality control. In Brazil, Anvisa RDC No. 12/01 specifies the enumeration of coliforms as one of the parameters for evaluating cheese quality. The aim of this study was to produce a quantitative RM for proficiency testing (PT) for use in the testing of enumeration of coliforms in cheese matrixes. A sample of an ultra-filtered cheese with a coliforms count of <3.0 MPN/g and a total n? of viable aerobes of 1.2 × 103 CFU/g was used as the matrix to produce the RM. The ultra-filtered cheese matrix was distributed in flasks, contaminated with a specific concentration of an Escherichia coli strain and submitted to freeze-drying. Sucrose was used as the cryo-protector. The RM produced was considered sufficiently homogeneous and stable at ≤ ?70?C during the entire study period (348 days). The material was also considered sufficiently stable at 4?C for six days, but instable at 30?C and 35?C for the same period. At ?20?C the RM was sufficiently stable for 161 days. It was concluded that the material showed all the necessary requirements for a quality RM to be used as PT items and could be transported to the laboratories taking part in a PT at up to 4?C for up to 6 days, since the results indicated maintenance of the cell concentrations during this period. This is the first study to describe a methodology for producing RM containing coliforms in a cheese matrix. 展开更多
关键词 COLIFORMS CHEESE reference Material Proficiency Test
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Multi-collector ICP-MS Analysis of Pb Isotope Ratios in Rocks: Data, Procedure and Caution 被引量:2
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作者 NIU Yaoling 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2003年第1期44-58,共15页
The authors measured Pb isotope compositions of seven USGS rock referencestandards, i.e. AGV-1, AGV-2, BHVO-1, BHVO-2, BCR-2, BIR-1/1 and W-2, together with NBS 981 using amicromass isoprobe multi-collector inductivel... The authors measured Pb isotope compositions of seven USGS rock referencestandards, i.e. AGV-1, AGV-2, BHVO-1, BHVO-2, BCR-2, BIR-1/1 and W-2, together with NBS 981 using amicromass isoprobe multi-collector inductively-coupled plasma mass spectrometer (MC-ICP-MS) at theUniversity of Queensland. ^(203)Tl-^(205)Tl isotopes were used as an internal standard to correctfor mass-dependant isotopic fractionation. The results for both NBS 981 and USGS rock standardsAGV-1 and BHVO-1 are comparable to or better than double- and triple-spike TIMS (thermal ionizationmass spectrometry) data in precision. The data for BHVO-2 and, to a lesser extent, AGV-2 and BCR-2are reproducibly higher for ^(206)Pb/^(204)Pb, ^(207)Pb/^(204)Pb and ^(208)Pb/^(204)Pb thandouble-spike TIMS data in the literature. The authors also obtained the Pb isotope data for BIR- 1/1and W-2, which may be used as reference values in future studies. It is found that linearcorrection for Pb isotopic fractionation is adequate with the results identical to those correctedfollowing an exponential law or a power law. Precise ^(207)Pb/^(206)Pb, ^(208)Pb/^(206)Pb and^(208)Pb/^(207)Pb ratios can be acquired for sample solutions with Pb>=1 ppb. However, Pb isotoperatios involving ^(204)Pb (i.e., ^(206)Pb/^(204)Pb, ^(207)Pb/^(204)Pb and ^(208)Pb/^(204)Pb) arereliable for solutions with Pb>=40 ppb. The errors for Pb isotope ratio analysis using the MC-ICP-MSare dominated by errors in the analysis of ^(204)Pb, which is commonly ascribed to the difficultyand imprecise correction for a ^(204)Hg isobaric interference. It is found however that the majorerrors on ^(204)Pb come from the tailings of mass ^(203)Tl and mass ^(205)Tl These mass tailingslead to over-subtraction of the baseline for ^(204)Pb, which is measured at +-0.5 amu on both sidesof mass-204 (i.e., at amu 203.5 and 204.5 respectively). Such errors are insignificant for Pb-richsample solutions (i.e., high Pb/Tl ratios), but can be severe for low-Pb sample solutions whenover-'spiked' with Tl. Experiments in this study suggest that a minimum concentration ratio ofPb/Tl>5 in Tl-'spiked' solutions be required to ensure reliable ^(206)Pb/^(204)Pb, ^(207)Pb/^(204)Pband ^(208)Pb/^(204)Pb isotopic ratios. The tailings of ^(203)Tl and ^(205)Tl can also lead toover-subtraction of baselines for ^(202)Hg (at amu 202.5) and ^(206)Pb (at amu 205.5). Therefore,the elegance of using ^(203)Tl and ^(205)Tl isotopes for mass fractionation correction becomes asevere problem in low-Pb rock solution-caution is required. Alternative internal standards for massfractionation correction may be considered. Of course, significant instrumental refinement inabundance sensitivity is in demand. 展开更多
关键词 MC-ICP-MS Pb isotope ratios reference materials
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Comparative analysis on homogeneity of Pb and Cd in epoxy molding compounds
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作者 Kyun-Gmee LEE Yong-Keun SON +2 位作者 Jin-Sook LEE Tai-Min NOH Hee-Soo LEE 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第A01期160-164,共5页
Reference materials for quantitative determination of regulated heavy metals, such as Pb and Cd in electronic components, were designed and investigated in terms of stability and homogeneity. Reference materials with ... Reference materials for quantitative determination of regulated heavy metals, such as Pb and Cd in electronic components, were designed and investigated in terms of stability and homogeneity. Reference materials with two concentration levels of heavy metals were prepared by spiking Pb and Cd compounds to epoxy molding compounds made by mixing silica powders and epoxy resin. The concentration changes of the reference materials during stability test for 1 a were not observed. In the homogeneity assessment, the as-prepared reference materials were studied by using three different analytical tools, inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray fluoroescence spectrometry (XRF) and laser ablation ICP mass. The results show different homogeneities by the characteristics of analytical tools and the materials. 展开更多
关键词 epoxy molding compound PB CD reference materials HOMOGENEITY
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Theoretical and experimental assessment of a novel method to establish the complete measurement range of the calorimeter and its limit of detection and quantification
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作者 Vesna Krstic 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2022年第4期466-473,共8页
For determining the accuracy of a calorimeter over the instrument’s entire measuring range,a novel method has been established.For this new approach,(a)benzoic acid(C_(6)H_(5)CO_(2)H) as a certified reference materia... For determining the accuracy of a calorimeter over the instrument’s entire measuring range,a novel method has been established.For this new approach,(a)benzoic acid(C_(6)H_(5)CO_(2)H) as a certified reference material(CRM),(b)SiO_(2) and(c)a mixture of CRM benzoic acid and SiO_(2) have been used.To illustrate the essential difference between 1)the novel analytical method for control of the entire measurement range and 2)the calorimeter calibration,both applications of benzoic acid(BA)have been demonstrated.An experimental result showed that BA was successfully used to check the whole calorimeter measurement range.The results also showed that the same new method was successfully applied to determine the limit of detection and quantification.A new instrument testing process and a new measurement technique have thus been established.In this way,the cost of using CRM to control the accuracy of measuring the entire measuring range of the calorimeter,as shown in this paper,is minimized.The requirements of the ISO/IEC 17025:2017 standard are satisfied.ISO/IEC 17025:2017,together with ISO 9001:2015(quality management systems),ISO 14001:2015(relate to environmental protection)and ISO45001:2018(occupational safety),constitute an integrated quality system by which a testing laboratory may also accredit. 展开更多
关键词 Benzoic acid Certified reference material The limit of detection/quantification Measurement range Quality control CALORIMETER Environmental protection
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