W-000.17.210 [2021-03] Calcium in Water, Determination Using Atomic Emission Spectrometry (ICP-AES)

Application/Purpose

This method describes how to determine the calcium content in water using atomic emission spectroscopy.  In principle, this method is suitable for determining the concentrations of the following in water: silver, aluminum, arsenic, boron, barium, beryllium, bismuth, calcium, cadmium, cobalt, chromium, copper, iron, potassium, lithium, magnesium, manganese, molybdenum, sodium, nickel, phosphorus, lead, sulfur, antimony, selenium, silicon, tin, strontium, titanium, vanadium, tungsten, zinc and zirconium.

Scope of Application

Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods

Calcium ions (like magnesium ions) are present in all natural waters at greater or lesser concentrations and are among the minerals that bring about hardness in water.

Principle

Inductively coupled plasma atomic emission spectroscopy (ICP-AES) is an analytical technique for detecting and determining concentrations of elements by measuring their line-emission spectra. The solution under analysis is atomized and the aerosol is transported into an inductively coupled plasma (ICP) with the aid of a carrier gas at which point the elements enter an excited and unstable state. When they return to their ground state, the atoms radiate. Their emission spectra are measured using a spectrophotometer. The intensity of the emission spectra is measured with detectors (photomultipliers). Quantitative results are possible through calibration with a standard, though over a wide range (normally multiple orders of magnitude) a linear relationship between the intensity of the line-emission spectra and the concentration of the elements exists. The elements can either all be determined simultaneously or each one sequentially.

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