GB/T 37907-2019 English PDF (GBT37907-2019)

This Standard specifies the determination method of sulfide and cyanide contents in reclaimed water -- ion chromatography. This Standard is applicable to the determination of sulfide and cyanide contents in reclaimed water. The measurement range is 0.5 ~ 100. When the mass concentration exceeds 100, it needs to be measured after dilution. This Standard is also applicable to the determination of sulfide and cyanide contents in surface water and drinking water.

GB/T 37907-2019
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 13.060.50;71.040.40
G 76
Reclaimed water quality - Determination of sulfide and
cyanide - Ion chromatography
ISSUED ON: AUGUST 30, 2019
IMPLEMENTED ON: JULY 01, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Principle ... 4
4 Reagents or materials ... 4
5 Instruments and apparatuses ... 5
6 Sample ... 6
7 Determination steps ... 6
8 Result calculation ... 8
9 Allowable difference ... 8
Appendix A (Informative) Ion chromatography conditions setting and standard chromatogram examples ... 9
Reclaimed water quality - Determination of sulfide and
cyanide - Ion chromatography
1 Scope
This Standard specifies the determination method of sulfide and cyanide contents in reclaimed water -- ion chromatography.
This Standard is applicable to the determination of sulfide and cyanide contents in reclaimed water. The measurement range is 0.5 μg/L ~ 100 μg/L. When the mass concentration exceeds 100 μg/L, it needs to be measured after dilution. This Standard is also applicable to the determination of sulfide and cyanide contents in surface water and drinking water.
2 Normative references
The following documents are indispensable for the application of this document. For dated references, only the dated version applies to this document. For undated references, the latest edition (including all amendments) applies to this document.
GB/T 5750.2, Standard examination methods for drinking water - Collection and preservation of water samples
GB/T 6682, Water for analytical laboratory use - Specification and test methods
3 Principle
The sample enters the column. With the flow of the eluent, the sulfide and cyanide in the sample exchange and elute with the active exchange group on the column repeatedly. According to the difference of retention characteristics of sulfide and cyanide on the column, it achieves separation. Use ampere detector to perform detection. Use the relative retention time of the
chromatographic peak for qualitative determination; use the peak area or peak height for quantitative determination.
4 Reagents or materials
Caution -- The strong acid and strong base which are used in this
Standard are corrosive. Avoid inhalation or contact with the skin during 6 Sample
6.1 Collection and preservation of samples
6.1.1 Collect water samples in accordance with the provisions of GB/T 5750.2. After collecting the samples to a brown glass bottle, use sodium hydroxide solution (40 g/L) to adjust the pH to 9.0 ~ 10.0. The sampling bottle shall be filled with water samples, so that there are no air bubbles in the bottle. Immediately seal it; avoid direct sunlight during transportation.
6.1.2 The collected water sample shall be analyzed as soon as possible; otherwise, it shall be stored at low temperature (0°C ~ 4°C) and protected from light; the measurement shall be completed within 24 h.
6.2 Interference and sample pretreatment
6.2.1 When the water sample contains cobalt (> 0.05 mg/L), it is necessary to add 1 mL of sulfuric acid solution to adjust the water sample to pH< 2.0; then, use an all-glass distillation device for distillation; then, use 10 mL of sodium hydroxide solution (10 g/L) to absorb; lastly, filter it through a 0.22 μm water- phase filter and test.
6.2.2 Water sample that contains oxides such as free chlorine (> 1.0 mg/L) will interfere with the determination of cyanide. Sodium sulfite solution can be added before distillation to eliminate interference. Measure two samples of the same volume; add 1 ~ 3 piece(s) of potassium iodide-starch test paper to one of the samples; add sulfuric acid solution to acidify; drop sodium sulfite solution to the potassium iodide-starch test paper until it becomes colorless from blue; write down the amount. For another sample, do not add potassium iodide- starch test paper; only add the above-mentioned amount of sodium sulfite solution.
6.2.3 Water sample that contains nitrite ions (> 50 mg/L) will interfere with the determination of cyanide. Sulfamic acid can be added before distillation to eliminate the interference. For 1 mg of nitrite, 2.5 mg of sulfamic acid is needed. 7 Determination steps
7.1 Setting of the ion chromatography conditions
Debug the ion chromatograph according to the best conditions that are provided in the instrument instruction manual. Set the chromatographic conditions as follows: