GB/T 9721-2006Chemical reagent - General rules for the molecular absorption spectrophotometry (ultraviolet and visible) (English PDF)

3.1 Absorption peak

It refers to the wavelength of the absorption spectrum at the maximum absorbance value, in the unit of nm.

3.2 Absorption spectrum

It refers to, when the concentration of the substance to be determined and the thickness of the absorption pool are constant, the curve of the absorbance (or any function of the absorbance) corresponding to the wavelength (or any function of the wavelength).

3.3 Thickness (L)

It refers to the distance between the two parallel and transparent internal surface planes of the absorption pool, in the unit of mm or cm.

3.4 Amount-of-substance concentration (c)

It refers to the ratio of the amount of substance to the volume of solution, in the unit of mol/L.

3.5 Molar absorptivity (epsilon)

It refers to the absorptivity epsilon with the thickness expressed in cm AND the concentration expressed in mol/L, in the unit of L/(cm·mol).

5.1 Water

The water used to prepare solution for the instrument calibration shall comply with the level II water requirements in GB/T 6682-1992. The water used for sample test shall be of the level II or level III water in GB/T 6682-1992 in accordance with the requirements of the product standard.

5.2 Organic solvents

SELECT appropriate solvent based on the requirements of the product standards, and CHECK whether the solvent used for the test complies with the requirements in the vicinity of the determination wavelength; AND it shall be […]

5.3 Buffer solution

It shall be prepared in accordance with the requirements of the product standard; AND the reagents used shall be free from interference absorption in case of determination at the UV zone.

5.4 Standard sample solution

It shall be prepared together with the sample solution to be determined in accordance with the requirements of the product standard.

7.1 Selection of determination conditions

7.1.1 Light source

SELECT the light source based on the determined wavelength; USE the hydrogen lamp (or tritium lamp) when the determined wavelength is 200 nm ~ 350 nm, AND the tungsten lamp (or iodine tungsten lamp) when the determined wavelength is 350 nm ~ 850 nm.

7.1.3 Determined wavelength

In the development of product standards, the determined wavelength is determined in accordance with the position of the substance to be determined, which is generally selected from the wavelength range of the maximum absorbance.

7.1.4 Absorption pool

In accordance with the requirements of use, it may, in accordance with the provisions of clause 2.2 "Matching of absorption pool" in JJG 178-1996 OR the provisions of 12 "Specification of standard substance quartz absorption pool" in JJG 682-1990, select the absorption pool; […]

7.1.5 Sample solution

It shall be prepared in accordance with the provisions of product standards.

The solution shall be uniform and non-scatter, that is, there shall not be bubbles and suspended substances that affect the absorption of light.

7.2 Determination method

7.2.1 Absorption curve method

When using the automatic recording instrument, it can automatically scan and draw the absorption curve.

7.2.2 Working curve method

PREPARE more than 4 standard solutions with the concentrations in appropriate proportions in accordance with the provisions of the product standards; USE the blank solution (or solvent) as the reference solution, and meanwhile USE the absorbance of the blank solution (or solvent) to conduct calibration.

7.2.5 Sensitivity determination

CONDUCT determination in accordance with the specified conditions of the product standards. Sensitivity can be expressed by the molar absorptivity.

7.2.6 Determination of mass absorptivity

CONDUCT determination in accordance with the specified conditions of the product standards.