ISO 24181-1:2024 レアアース — 個々のレアアース金属およびその酸化物中の非レアアース不純物の定量 — ICP-AES — Part 1:Al、Ca、Mg、Fe、Si の分析 | ページ 6

3.1

inductively coupled plasma

ICP

high-temperature (8 000 K to 10 000 K) discharge of energy generated in a ionized gas, usually argon, produced by a radio frequency controlled varying magnetic field, originating from an AC current flowing in a water-cooled copper coil or in an induction coil which surrounds tubes through which the gas flows

3.2

inductively coupled plasma-atomic emission spectroscopy

ICP-AES

type of atomic spectroscopy in which the optical radiation emitted by atoms and ions present in an inductively coupled plasma (3.1) is observed and measured

3.3

impurity element

very small amount or trace of element in an otherwise pure substance

3.4

matrix solution

solution of the high purity metal or oxide of an individual rare earth element at a certified concentration(s), suitably prepared known sample which is used for LOQ (3.13) confirmations and preparation of calibration solutions (3.6)

Note 1 to entry: Impurity elements (3.3) in high purity metals or oxides of individual rare earth elements shall be determined prior to analyses, and shall be controlled to less than a mass fraction of 0,001 % or 0,000 1 % depending on the concentration of each impurity element in the high purity rare earth metal or oxide for the preparation of the matrix solution.

3.5

stock solution

solution of a high purity chemical compound containing an impurity element (3.3) at a certified concentration(s) suitably prepared known sample, which is used for the preparation of calibration solutions (3.6)

Note 1 to entry: The purity of the chemical compound containing the same single element as an impurity element (3.3) for the stock solution (3.5) shall be generally controlled to more than a mass fraction of 99,9 %.

3.6

calibration solution

solution prepared with the addition of matrix solution (3.4) and any stock solution (3.5) for constructing a calibration curve

Note 1 to entry: For the calibration curve method (3.12) , the matrix solution (3.4) prepared without the addition of any stock solution is required as a blank solution. The concentration of the impurity elements (3.3) in this blank solution is taken to be zero.

3.7

test sample

solid substance of a rare earth metal or oxide for the determination of an impurity element (3.3)

3.8

test portion

quantity of material drawn from the test sample (3.7) (or from the laboratory sample if both are the same) and on which the test or observation is actually carried out

[SOURCE:ISO 78-2:1999, 3.3]

3.9

test solution

solution of the weighed test sample (3.7) prepared by the acid digestion method (3.10)

3.10

acid digestion method

sample preparation method of dissolving test samples (3.7) into a solution by adding acids and heating until the complete decomposition of the matrix is achieved

3.11

calibration curve method

method for quantifying impurity elements (3.3) in a test sample (3.7) using a calibration curve prepared with calibration solution (3.6) containing a targeted impurity element (3.3) with far lower concentrations of non-targeted elements than that of the targeted impurity element (3.3)

3.12

matrix matching

preparation process to fabricate a calibration solution (3.6) with the same chemical composition of test solution (3.9) for the calibration curve method (3.11)

3.13

limit of quantification

LOQ

lowest amount of an analyte that is quantifiable with a given confidence level

Note 1 to entry: The limit of quantification is calculated as ten times the standard deviation of the measurement result of blank, which is the matrix solution prepared without the addition of any stock solutions.

Note 2 to entry: The value of LOQ is used as a threshold value to assure quantitative measurement of an analyte accurately.