Copper is an essential trace element for plant metabolism as well as the human diet, with a daily requirement of around 2.0 mg. Due to its malleability, thermal and electrical conductivity, and corrosion resistance, copper is also used in a variety of industrial and technological applications. Copper may also be present in natural water and effluents due to widespread use to control biological growths in reservoirs and distribution pipes.
The amount of copper in a sample can be determined colorimetrically and potentiometrically with a cupric ISE. Colorimetrically the bicinchoninate method can be used with copper in the sample reacting with a salt of bicinchoninic acid forming a purple colored complex. The color intensity of the sample is proportional to the copper concentration in the sample. The cupric ISE is a solid-state sensor that can measure copper in the cupric (Cu+2) form. The cupric ISE can be used as an indicator in complexometric titrations with metals using a Cu-EDTA titrant.
Hanna Instruments offers a variety of technologies to measure Copper. Colorimetrically spectrophotometers, photometers and Chemical Test Kits (CTK) are available. For a potentiometric measurement, portable and benchtop pH/ISE meters are available to use with the copper ISE for direct ion-concentration measurements. Potentiometric titration systems are available that can be used for direct measurement or for titration.
Below are the most common products used for copper measurement.
Spectrophotometers are available that have copper methods in several ranges pre-programmed into the meter. The spectrophotometer offers the highest precision due to the quality of the optical system that has a wavelength accuracy of +/- 1.5 nm. The spectrophotometer allows for custom methods to be developed.
Benchtop photometers include multiparameter versions for water treatment, wastewater treatment, aquaculture, environmental and pools & spas. Each photometer is customized to have the parameters used by a specific industry. All benchtops have a digital pH electrode input allowing it to be used as a traditional pH meter.
Single parameter portable photometers are available in high and low ranges. The portable photometers have a CAL Check feature that allows for performance verification and if needed, recalibration using the CAL Check standards. The portable meters are available as a meter only or as a kit. The kit version include a rugged carrying case and CAL Check standards.
Checker HC, like a chemical test kit, are reagentbase d design in which there is a color change based on concentration. The handheld colorimeters, like portable and benchtop instrumentation, use the Beer-Lambert principle to determine the color change. The color change is measured by a photoelectric cell which is more accurate than subjective visual interpretation.
Reagents include the reagents used with chemical test kits and photometers.
Titrators are available to perform titrations using the cupric ISE and a Cu-EDTA titrant. Titration systems offer a precision dosing system to determine the precise amount of titrant used. Titration systems are available with one or two analog board inputs and options for one or two dosing pumps.
Benchtop pH/ISE meters
Benchtop pH/ISE meters include two channel option in which a pH probe can be connected to one channel and the copper ISE to the other. The benchtop meters have the ion charge and formula weight pre-programmed for use with the copper ISE. The benchtop meters also have incremental methods pre-programmed including the known addition, known subtraction, analyte addition, and analyte subtraction methods.
Portable pH/ISE Meters
Portable pH/ISE meters allow the flexibility to perform an ISE measurement with a portable even though the ISE measurement method is more suitable to a benchtop environment due to the addition of the ISA to raise the pH and the use of a magnetic stirrer to keep the sample homogenous. The portable pH/ISE meter has the ion charge and formula weight pre-programmed for concentration measurements.
Cupric ISE are potentiometric devices used for the rapid determination of free cupric ions in samples, and as a detector for the titration of cupric with EDTA. Cupric sensors are “electrodes of the third kind” because they detect cations, which also form low-solubility salts with sulfide anions and silver. The electrode functions as a sensor or ionic conductor. The mixed cupric sulfide/silver sulfide solid-state membrane produces a potential change due to changes in the sample’s cupric ion activity. When the ionic strength of the sample is fixed by the addition of ISA, the voltage is proportional to the concentration of cupric ions in solution and the electrode follows the Nernst equation.
The cupric ISE is available as a combination version with both indicating half cell and reference half cell or available as an indicating half cell that will be used with a separate reference half cell.
Solutions for copper measurement include ISE standards and ISA for calibration and measurement. Other solutions include the CAL Check standards for verifying and, if needed, the calibration of our portable photometers. Each CAL Check standard is supplied with a Certificate of Analysis stating the accuracy and traceability of the standard.
Accessories include spare cuvettes and caps for photometers, and magnetic stirrers to ensure adequate mixing when using an ISE.