The determination of micro-concentration gradients on the surfaces of solid samples by means of the laser-microprobe

✍ Scribed by M.S.W. Webb; J.C. Cotterill

• Publisher: Elsevier Science
• Year: 1968
• Tongue: English
• Weight: 272 KB
• Volume: 43
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/s0003-2670(00)89231-4

✦ Synopsis

a 50% decrease over the blank average of 7.8,ug of oxygen found for the quartz thimble. A marked improvement in blank reproducibility was also achieved with the PBN thimble; the standard deviation for the PBN thimble oxygen blank was 0.82 ,ug of oxygen compared with 1.8 pg osygen for the quartz thimble. Both the reduced blank and the improved blank stability will be important for operators doing parts-per-million osygen analyses. The significant reduction of the osygen blank level and the increased stability of the oxygen blank show the value of using the pyrolytic boron nitride thimble in commercially available carrier gas fusion analyzers. The PBN thimble has been in use in our instrument ior over two years without apparent clam$ge or deleterious effects. This long life has more than offset the initial cost of the PBN crucible. In addition, use of the PBN thimble saves time in operator training, crucible packing, degassing and down time.