A Laboratory Experiment Involving Paper-Chromatography and Statistics

This article suggests a paper chromatographic separation of the dyes in commercial black inks, which has been designed for completion in one 3-hour laboratory period with the use of equipment and solvents found in practically all laboratories. The experiment gives very satisfactory results, and allows the student to become familiar with the general field of paper chromatography and some of the factors which affect Rf values of constituents of mixtures. It also may be used to demonstrate the use of simple statistical tests, if desired

Determination of Copper in Lead and Lead Base Alloys

This work was undertaken in an effort to develop a rapid method for the determination of copper in the range of 0.01 to 0.06% in lead alloys and in the range of 0.001 to 0.005% in lead. A visual and a photometric method are suggested, based on the color developed by copper in concentrated hydrochloric acid. Iron interferes with the determination, but this interference is reduced by use of an aluminum file in the visual method, and is corrected for in the photometric method by determination of the Lron as the thiocyanate. The visual method is very rapid, is accurate to plus or minus 0.1% in the range 0.01-0.06%, and is suggested as a control method for alloys. The photometric procedure is accurate to better than 0.006% in the range of 0.01 to 0.05% and 0.0005% in the range 0.001 to 0.005%, and is suggested as a routine or control method

A Laboratory Experiment Involving Paper-Chromatography and Statistics

This article suggests a paper chromatographic separation of the dyes in commercial black inks, which has been designed for completion in one 3-hour laboratory period with the use of equipment and solvents found in practically all laboratories. The experiment gives very satisfactory results, and allows the student to become familiar with the general field of paper chromatography and some of the factors which affect Rf values of constituents of mixtures. It also may be used to demonstrate the use of simple statistical tests, if desired

Determination of Copper in Lead and Lead Base Alloys

This work was undertaken in an effort to develop a rapid method for the determination of copper in the range of 0.01 to 0.06% in lead alloys and in the range of 0.001 to 0.005% in lead. A visual and a photometric method are suggested, based on the color developed by copper in concentrated hydrochloric acid. Iron interferes with the determination, but this interference is reduced by use of an aluminum file in the visual method, and is corrected for in the photometric method by determination of the Lron as the thiocyanate. The visual method is very rapid, is accurate to plus or minus 0.1% in the range 0.01-0.06%, and is suggested as a control method for alloys. The photometric procedure is accurate to better than 0.006% in the range of 0.01 to 0.05% and 0.0005% in the range 0.001 to 0.005%, and is suggested as a routine or control method