Standard Methods: 3500-Cu C: Copper by Bathocuproine

Summary
Analytes
Revisions
Data and Sites

Official Method Name

3500-Cu C. Bathocuproine Method

Current Revision

Standard Methods Online

Media

WATER

Instrumentation

Spectroscopy (Colorimetry; Photometry)

Method Subcategory

Inorganic

Method Source

Standard Methods

Citation

Standard Methods Online - Standard Methods for the Examination of Water and Wastewater

Brief Method Summary

Cuprous ion forms a water-soluble orange-colored chelate with bathocuproine disulfonate (2,9-dimethyl-4,7-diphenyl-1,10-phenanthrolinedisulfonic acid, disodium salt). While the color forms over the pH range 3.5 to 11.0, the recommended pH range is between 4 and 5. The sample is buffered at a pH of about 4.3 and reduced with hydroxylamine hydrochloride. The absorbance is measured at 484 nm.

Scope and Application

This method can be used for potable waters.

Applicable Concentration Range

Up to at least 5 mg/L with a sensitivity of 20 ug/L

Interferences

A list of interferences and the concentration at which they interfer is included in a table in the method. They include, among others, aluminum, cadmium, calcium chromium, iron (II and III), and magnesium.

Quality Control Requirements

See Section 3020 Quality Assurance/Quality Control.

Sample Handling

Copper ion tends to be adsorbed on the surface of sample containers. Therefore, analyze samples as soon as possible after collection. If storage is necessary, use 0.5 mL 1 + 1 HCl/100 mL sample, or acidify to pH <2 with HNO3, to prevent this adsorption.

Maximum Holding Time

Relative Cost

Less than $50

Sample Preparation Methods

This method has 1 analyte associated with it.

Analyte	Detection Level	Bias	Precision	Pct False Positive	Pct False Negative	Spiking Level
Copper(7440-50-8) Copper Copper (metallic) Cu	20.000 ug/L	0Rel. Error (ML)	4.10 % RSD (ML)			1000.00 ug/L

Precision Descriptor Notes:	A synthetic sample containing 1000 ug Cu/L, 500 ug Al/L, 50 ug Cd/L, 110 ug Cr/L, 300 ug Fe/L, 70 ug Pb/L, 50 ug Mn/L, 150 ug Ag/L, and 650 ug Zn/L was analyzed in 33 laboratories by the bathocuproine method, with a relative standard deviation of 4.1% and a relative error of 0.3%.
Detection Level Note:	The minimum detectable concentration is 20 ug/L with a 5-cm cell.

Revision	PDF/Link
Standard Methods Online
As Method 3500-Cu B in Standard Methods 18th Edition (1992)
As Method 3500-Cu B in Standard Methods 19th Edition (1995)
Standard Methods 18th, 19th, 20th ed.

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Standard Methods: 3500-Cu C: Copper by Bathocuproine

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