BS EN 890-2012 pdf download.Chemicals used for treatment of water intended for human consumption – Iron (III) sulfate solution.
The suitable concentration ranges of this method are:
— As 0,1 mg/kg to 0.5 mg/kg;
– Sb: 0.1 mg/kg to 0.5 mg/kg;
— Se : 0,1 mg/kg to 0,5 mg/kg.
For higher concentrations the sample solution shall be diluted.
8.5.2 Principle
Arsenic (As). antimony (Sb) and selenium (Se) are reduced to the elemental hydrides AsH3, SbH3 and SeH4 by sodium tetrahydroborate. The gaseous hydrides are conveyed with argon gas to a heated quartz cuvette and thermally decomposed. The absorption of the atoms is measured in the light path of an atomic absorption spectrometer at a wavelength specific to the element. The concentrations are calculated by means of calibration curves.
8.5.3 Reagents
All reagents shall be of a recognized analytical grade and the water used shall conform to the grade 3 in accordance with EN ISO 3696.
B.5.3.1 Hydrochloric acid (HCI), solution, mass fraction 30 %.
B.5.3.2 L-ascorbic acid, solution 100 gIl.
B.5.3.3 Oxalic acid, solution 100 gIl.
8.5.3.4 Potassium iodide, solution 100 gIl.
B.5.3.5 Sulfuric acid solution, c(H2S04) = 1 mol/l.
B.5.3.6 Sodium tetrahydroborate solution, mass fraction of 5 % NaBH4 in NaOH solution of a mass fraction of 1 %.
8.5.3.7 Element stock solutions, c’0 (As. Sb, Se) = 1 g/l.
B.5.3.8 Standard element solutions. c1 (As. Sb. Se) = 10 mg/I. to be prepared by dilution of B.5.3.7.
B.5.3.9 Standard element solutions, c2 (As, Sb, Se) = 0,1 mg/I, to be prepared by dilution of B.5.3.8.
Ordinary laboratory apparatus and glassware together with the following.
B.5.4.1 Pipettes, capacity 5 ml, 10 ml and 20 ml.
B.54.2 Graduated cylinder, capacity 50 ml.
B.5.4.3 Volumetric flasks, capacity 100 ml.
B.5.4.4 Atomic absorption spectrometer.
B.5.4.5 Electrode-less discharge lamps for the de1trmiriatiun UI MS, OU dFiU O.
8.5.4.6 Hydride system consisting of a heatable quartz cuvette, a reaction unit and a control unit.
B.5.4.7 Argon gas supply.
B.5.5 Procedure
B.5.5.1 Spectrometer settings
The atomic absorption spectrometer (B.5.4.4) and the hydride generator unit (8.5.4.6) are adjusted in accordance with the operating manual issued by the manufacturer. The spectrometer is operating at the wavelength for each element:
— As: 193,7 nm:
— Sb:217,6nm;
— Se:196,Onm.
The quartz cuvette is heated to 900 °C.
B.5.5.2 Measurement of arsenic and antimony
Take 20 ml of the sample solution (5.2.3.1.5) with a pipette (B,5.4.1) and transfer to a 100 ml volumetric flask (B.5.4.3). Add with a graduated cylinder (B.5.4.2) 30 ml oxalic acid (B.5.3.3), 10 ml potassium iodide (B.5.3.4), 5 ml ascorbic acid (B.5.3.2) and 5 ml hydrochloric acid (8.5.3.1), then make up to the mark with water. The prepared solution shall be allowed to stand for 3 h to ensure complete reaction. Then transfer 5 ml of the solution with a pipette (B.5.4.1) to the reduction vessel, add 10 ml sulfuric acid (B.5.3.5) and start the hydride control unit. The solution is reduced with NaBH4 and immediately AsH3 and SbH3 are transferred with the argon gas (8.5.4.7) to the
900 C heated quartz cuvette. Measure the absorption of arsenic with an arsenic specific lamp (B.5.4.5) at
wavelength 193,7 nm. Measure the absorption of antimony with an antimony specific lamp (B.5.4.5) at wavelength 217,6 nm.
B.6.2 Principle
Divalent mercury in the sample solution (5.2.3.1.5) is reduced to the element by tin (II) chioride or sodium tetrahydroborate solutions. Mercury is stripped from this solution in an inert gas stream and converted to the amalgam on a gold/platinum gauze for the purpose of enrichment. Mercury is released again by rapidly heating the absorber and conveyed to a quartz cuvette. The absorption of the mercury atoms measured in a light path of an atomic absorption spectrometer at a wavelength specific to mercury (253,7 nm). The concentration is calculated by means of a calibration curve.
B.6.3 Reagents
All reagents shall be of a recognized analytical grade and the water used shall conform to the grade 3 in
accordance with EN ISO 3696.
B.6.3.1 Hydrochloric acid (HCI), solution, mass fraction 30 %.
B.6.3.2 Sulfuric acid solution, c(H2S04) = 1 mol/l.
8.6.3.3 Tin (II) chloride solution, mass fraction of 10 % of SnCI2 in HCI solution of a mass fraction of 5 %.
B.6.3.4 Stabilizing solution (0.59 KMnO4 in 100 ml of water).
B.6.3.5 Mercury stock solution, c0 (Hg) I g/l.
B.6.3.6 Standard mercury solution, c1 (Hg) = 10 mg/I to be prepared by dilution of B.6.3.5.
B.6.3.7 Standard mercury solution. c2 (Hg) = 0,1 mg/i, to be piepared by dilution of B.6.3.6.
B.6.3.8 Mercury reference solution, to be prepared by pipetting 1 ml, 2 ml, 4 ml. 8 ml and 10 ml of the standard solution (8.6.3.7) into a series of 100 ml volumetric flasks (B.6.4.2). adding 1 ml of stabilizing solution (B.6.3.4), 5 ml of hydrochloric acid (8.6.3.1). and making up to the mark with water.
The reference solutions contain 1 pg/I, 2 pg/i, 4 pg/I. 8 pg/i and 10 pg/I mercury.
B.6.3.9 Sample blank solution.
8.6.4 Apparatus
Ordinary laboratory apparatus and glassware together with the following:
B.6.4.1 Pipettes, capacity 1 ml, 5 ml and 10 ml.
B.6.4.2 Volumetric flasks, capacity 100 ml.BS EN 890-2012 pdf download.