Journal of research of the National Bureau of Standards最新文献

{"title":"The Role of the Robot in the Chemical Laboratory","authors":"C. Lochmüller","doi":"10.6028/jres.093.039","DOIUrl":"https://doi.org/10.6028/jres.093.039","url":null,"abstract":"","PeriodicalId":17082,"journal":{"name":"Journal of research of the National Bureau of Standards","volume":"93 1","pages":"267 - 268"},"PeriodicalIF":0.0,"publicationDate":"1988-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71362034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Open Tubular Liquid Chromatography and the Analysis of Single Neurons","authors":"J. Jorgenson, R. Kennedy, R. L. St.Claire, Jackie G. White, P. Dluzneski, J. S. D. Witt","doi":"10.6028/jres.093.094","DOIUrl":"https://doi.org/10.6028/jres.093.094","url":null,"abstract":"Liquid chromatography in open tubular columns (OTLC) offers a means of achieving separations of high resolving power within analysis times of minutes to hours. A theory which predicts the optimal dimensions for an open tubular column for a given set of analytical conditions has been developed [1]. This theory predicts that for a wide range of possible inlet pressures and analysis times the most efficient columns will result when the column inner diameter is between 1.5 and 3 prm. A column of 2 Mrm diameter and 2 meter length should be capable of producing a million theoretical plates for an analyte with a capacity factor of 10 (strongly retained) and a retention time of 100 minutes.","PeriodicalId":17082,"journal":{"name":"Journal of research of the National Bureau of Standards","volume":"93 1","pages":"403 - 406"},"PeriodicalIF":0.0,"publicationDate":"1988-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71362524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultra-Trace Elemental and Isotopic Quantification for Neonatal Nutrition Studies","authors":"L. J. Moore, J. Parks, M. T. Spaar, D. Beekman, E. Taylor, V. Lorch","doi":"10.6028/jres.093.064","DOIUrl":"https://doi.org/10.6028/jres.093.064","url":null,"abstract":"[I] Behne, D., J. Clin. Chem. Clin. Biochem. 19, 115 (1981). [2] Forbes, W. F., Finch, A., Esterby, S. R., and Cherry, W. H., Studies of trace metal Pb levels in human tissues-Ill. The investigation of Pb levels in rib and vertebra samples from Canadian residents, in Trace Substances in Environmental Health-X, Hemphill, D. D., (ed.), University of Missouri, Columbia, MO, 41 (1976). [3] Gawlik, D., Behne, D., and Gessner, H., Trace Ele. Med. 2, 64 (1985). [4] Juergensen, H., and Behne, D., J. Radioanal. Chem. 37, 375 (1977). [5] Iyengar, G. V., J. Path. 134, 173 (1981). [6] Iyengar, 0. V., Anal. Chem. 54, 554A (1982). [7] Iyengar, G. V., and Kollmer, W. E., Trace Ele. Med. 3, 25 (1986). [8] Iyengar, G. V., J. Radioanal. Nuel. Chem. 112, 151 (1987). Ultra-Trace Elemental and Isotopic Quantification for Neonatal Nutrition Studies","PeriodicalId":17082,"journal":{"name":"Journal of research of the National Bureau of Standards","volume":"93 1","pages":"328 - 331"},"PeriodicalIF":0.0,"publicationDate":"1988-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71362666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Importance of Chemical Blanks and Chemical Yields in Accurate Trace Chemical Analysis","authors":"W. R. Kelly, S. Hotes","doi":"10.6028/jres.093.025","DOIUrl":"https://doi.org/10.6028/jres.093.025","url":null,"abstract":"[1] Date, A. R., Preparation of Trace Element Reference Materials by a Co-precipitated Gel Technique, Report No. 101, Institute of Geological Sciences, London, March 1977. [2] Vanskii, L., Rosenberg, R. J., and Pitkinen, V., Nucl. Instrum. Methods 213, 343 (1983). [3] Rosenberg, R. J., and Viinskii, L., STOAV84, a Computer Program for an Automatic Gamma Spectrometer for Activation Analysis, Technical Research Centre of Finland, Research Notes 415, Espoo, 1985. [4) Rosenberg, R. I., Kaistila, M., and Zilliacus, R., J. Radioanal. Chem. 71, 419 (1982). Importance of Chemical Blanks and Chemical Yields in Accurate Trace Chemical Analysis","PeriodicalId":17082,"journal":{"name":"Journal of research of the National Bureau of Standards","volume":"93 1","pages":"228 - 232"},"PeriodicalIF":0.0,"publicationDate":"1988-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71361788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Range-Programming Stripping Voltammetry for Determination of Some Metals in Seawater","authors":"M. Czae, Jong-Hyup Lee","doi":"10.6028/jres.093.051","DOIUrl":"https://doi.org/10.6028/jres.093.051","url":null,"abstract":"Multielement capability of stripping analysis is one of its distinctive advantages described elsewhere [I]. Anodic stripping voltammetry with the use of differential pulse mode (DPASV) is uniquely suited [2], and therefore, applied extensively to the direct simultaneous determination of some trace metals (Zn, Cd, Pb, and Cu) in sea waters [3,4]. Even with the well-established procedure for a given sample, there still arises the problem introduced by simultaneously measuring relative concentrations of metal ions. A case in point is zinc and cadmium concentrations whose ratio sometimes is as high as 400 (12 ppb Zn/0.03 ppb Cd), and typically as high as 200 in raw surface sea waters [3]. In such a case, either one must run the entire steps separately by selecting suitable variables for each metal or pair of metals whose concentration ratio is adequate for simultaneous measurement, or the recorder scale must be changed during a single run to obtain the best results. The latter approach, difficult to achieve manually in practice, would rely on the application of an autoranging amplifier [5]. The use of an autoranging amplifier, however, has given rise to complications in evaluating the resulting voltammograms in most practical applications for analyzing seawaters [6]. The present work was initiated in order to overcome deterioration in readability and data quality, by developing a new programmedranging technique.","PeriodicalId":17082,"journal":{"name":"Journal of research of the National Bureau of Standards","volume":"93 1","pages":"296 - 298"},"PeriodicalIF":0.0,"publicationDate":"1988-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71362154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Isotope Dilution Mass Spectrometric (IDMS) Method for the Determination of Vitamin C in Milk","authors":"P. Ellerbe, L. Sniegoski, J. Miller, E. White","doi":"10.6028/jres.093.080","DOIUrl":"https://doi.org/10.6028/jres.093.080","url":null,"abstract":"(HCB) using the 1 C6 -labelled standard [6]. For the analysis of eggs, sample preparation involves initial treatment with phospholipase, extraction with acetone/hexane and then clean-up of the lipid extract on a water deactivated alumina column. Selected ion monitoring is for m/z 284 and 286 for HCB and 292 and 294 for I1 C6 ]HCB. The GC/MS program involves switching between a number of different ions, grouped for different retention time windows to enable monitoring of altogether 10 organochlorine pesticides plus respective isomers. For the future it is intended to increase the number of isotopically labelled standards utilized which will further increase the complexity of the multiple ion monitoring program.","PeriodicalId":17082,"journal":{"name":"Journal of research of the National Bureau of Standards","volume":"93 1","pages":"367 - 368"},"PeriodicalIF":0.0,"publicationDate":"1988-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71362291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prospects for Trace Analysis in the Analytical Electron Microscope","authors":"David B. Williams","doi":"10.6028/jres.093.081","DOIUrl":"https://doi.org/10.6028/jres.093.081","url":null,"abstract":"The analytical electron microscope (AEM) uses a high energy (>100 kV) beam of electrons to generate a range of signals from a thin foil sample as shown in figure la [1,2]. Various detectors are configured in the AEM to pick up most of the generated signals (fig. lb). Microanalysis is usually performed using the characteristic x-ray signal, detected by an energy dispersive spectrometer (EDS) although occasionally the electron energy loss spectrum is also used. This paper will emphasize x-ray microanalysis only. The specific advantages that the AEM has for microanalysis are two-fold. First the instrument can be operated as a high resolution transmission electron microscope, thus permitting the analytical information to be related directly to the microstructure of the sample. Second, in the AEM most microanalysis is performed with a probe size <z 10 nm and a specimen thickness < = 100 nm. This results in an analyzed volume 10' of that commonly encountered in bulk microanalysis, for example, in the electron probe microanalyzer (EPMA). This small volume means that the spatial resolution of microanalysis is relatively good (routinely <50 nm) but generally trace analysis in the AEM is relatively difficult, because generated signal intensities are low.","PeriodicalId":17082,"journal":{"name":"Journal of research of the National Bureau of Standards","volume":"93 1","pages":"369 - 372"},"PeriodicalIF":0.0,"publicationDate":"1988-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71362298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Imaging Microanalysis of Materials with a Finely Focused Heavy Ion Probe","authors":"R. Levi‐Setti, J. Chabala, Yuh‐Lin Wang","doi":"10.6028/jres.093.084","DOIUrl":"https://doi.org/10.6028/jres.093.084","url":null,"abstract":"Liquid metal ion sources (LMIS) in view of the quasi-point-like geometry of their emitting region and confined emission cone possess brightness (0I6 A cm 'sr-') which is adequate for the realization of high current density (I A cm-'), finely focused (>20 rm) probes. A 40 keV scanning ion microprobe, which makes use of a Ga LMIS (UCHRL SIM) is currently employed in our laboratory to obtain chemical maps of materials in a variety of interdisciplinary applications [1]. The instrument is composed of a two-lens focusing column, a hightransmission secondary ion energy analyzer and transport system, and an RF quadrupole mass filter for secondary ion mass spectrometry (SIMS). in addition, two-channel electron multiplier detectors, overlooking the target region, collect secondary electrons or ions for imaging of the surface topography and material contrast of a sample. Although a lateral resolution of 20 nm has been attained, sensitivity considerations favor operation at somewhat larger (50-70 nmt) probe size. The analytical image resolution is in fact critically dependent on the statistics of the mass analyzed signal [2], which in turn is determined by the rate of material removal by sputtering from the sample surface. Such a rate is proportional to the probe current, which decreases with the square of the probe diameter for chromatic-aberration-limited probes such as those extracted from LMIS. Thus at, e.g., 20 nm probe diameter, only 1-2 pA of probe current are available, the erosion rate is of the order 10-' rnonolayers/s and probe-size resolution can only be attained for elements of high ionization probability which will provide the highest signal statistics over an acceptable recording time (>I count/pixel in a 1024 x 1024 pixel scan for a 512 s acquisition time for the UC-HRL SIM). In view of the well known range of ionization probabilities (ion fractions) among sputtered atomic species, as well as of sputtering yields, the attainable analytical lateral resolution of finely focused probes becomes target-species dependent due to the above considerations. It also follows that for species difficult to ionize, high resolution SIMS imaging microanalysis is altogether precluded, unless by recourse to postionization techniques [3]. Two examples of applications of the UC-HRL SIM to the study of materials will be illustrated in the present context.","PeriodicalId":17082,"journal":{"name":"Journal of research of the National Bureau of Standards","volume":"93 1","pages":"377 - 379"},"PeriodicalIF":0.0,"publicationDate":"1988-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71362351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synchrotron Radiation Excited Fluorescence Micro-Analysis Using a New Imaging Technique","authors":"A. Knöchel, M. Bavdaz, N. Gurker, P. Ketelsen, W. Petersen, M. Salehi, T. Dietrich","doi":"10.6028/jres.093.085","DOIUrl":"https://doi.org/10.6028/jres.093.085","url":null,"abstract":"[I] Levi-Setti, R., Wang, Y. L., and Crow, G., Appl. Surf. Sci. 26, 249 (1986). [2] Levi-Setti, R., Chabala, J., and Wang, Y. L., Scanning Micros. Suppl. 1, 13 (1987). [3] Wang, Y. L., Levi-Setti, R., and Chabala, J., Scanning Microsc. 1 (1987). [41 Williams, D. B., Levi-Setti, R., Chabala, J. M., and Newbury, D. E., J. Microsc. (1987) in press. [51 Williams, D. B., Levi-Setti, R., Chabala, J. M., and Newbury, D. E., to be submitted to J. Microsc. [6] Chabala, J. M., Levi-Setti, R., Bradley, S. A., and Karasek, K. R., Imaging Microanalysis of Silicon Nitride Ceramics with a High Resolution Scanning Ion Microprobe. Appl. Surf. Sci. (1987) in press.","PeriodicalId":17082,"journal":{"name":"Journal of research of the National Bureau of Standards","volume":"93 1","pages":"379 - 383"},"PeriodicalIF":0.0,"publicationDate":"1988-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71362358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relative Sensitivity and Quantitation in Glow Discharge Mass Spectrometry: A Progress Report","authors":"J. Huneke","doi":"10.6028/jres.093.089","DOIUrl":"https://doi.org/10.6028/jres.093.089","url":null,"abstract":"It is hoped that the reader has acquired some appreciation of the problems, yet power of quantitative depth profiling using secondary ion mass spectrometry. The technique needs standards to obtain the accuracy needed for most of the applications at which it has excelled, and no doubt, this is a serious problem. Yet, in the field of analytical chemistry there exist very few techniques which exhibit quantitative accuracies in the 10-20% range without the use of standards, (techniques such as atomic absorbtion certainly require standards). These problems with quantitation are more than made up for by the technique's sub-ppm sensitivity, and universal applicability in terms of both sample type and elemental coverage, especially when one considers that this degree of sensitivity and accuracy is obtainable with depth resolution in the 50100 A range.","PeriodicalId":17082,"journal":{"name":"Journal of research of the National Bureau of Standards","volume":"93 1","pages":"392 - 394"},"PeriodicalIF":0.0,"publicationDate":"1988-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71362455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}