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How to Test Copper Purity

Copper, also, known as man̵7;s oldest metal, is a coveted metal for building and scrap material. All U.S. currency contains copper, and it is the most recycled of all the metals. Copper in its purest form is produced through smelting, which involves several stages of melting and purifying the copper content. The purity of copper is measured by what percentage of copper is found in the substance. The purest copper is over 99.99 copper. Use a spectrometer, which measures the amount of visible light that is absorbed by a solution, to test the purity of copper. The copper can remain in its solid form during testing and the spectrometer will not contaminate the sample.

Things You'll Need

Spectrometer
Small copper sample

Instructions

- 1
  Turn the spectrometer on and allow it to warm up. Adjust the wavelength to the correct setting for copper.
- 2
  Turn the knob on the front of the spectrometer to "0 percent T" to calibrate the machine.
- 3
  Wipe the outside of the tube holding the sample. Use a wipe to remove metal or fingerprints from the outside of the sample.
- 4
  Place the tube with the sample in the sample compartment and close the lid. Turn the knob to a reading of "100 percent T."
- 5
  Read the absorbance value on the scale to determine if the copper is pure. The spectrometer measures the individual component wavelengths of the fluorescent emission.
- 6
  Check the color of the copper. Copper in its purest form shows a light blue color. If other impurities are present, the color will be altered. If the copper is pure, a certain light frequency will form bands on the spectrometer that are characteristic of copper.

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