1、April 2012 Translation by DIN-Sprachendienst.English price group 12No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS
2、13.080.10!$Pf“1884567www.din.deDDIN ISO 11262Soil quality Determination of total cyanide (ISO 11262:2011)English translation of DIN ISO 11262:2012-04Bodenbeschaffenheit Bestimmung von Gesamtcyanid (ISO 11262:2011)Englische bersetzung von DIN ISO 11262:2012-04Qualit du sol Dosage des cyanures totaux
3、(ISO 11262:2011)Traduction anglaise de DIN ISO 11262:2012-04www.beuth.deDocument comprises pagesIn case of doubt, the German-language original shall be considered authoritative.2003.12 A comma is used as the decimal marker. Contents Page National foreword .3 National Annex NA (informative) Bibliogra
4、phy 3 Introduction .4 1 Scope 5 2 Normative references 5 3 Terms and definitions .5 4 Principle 6 4.1 Direct liberation of hydrogen cyanide using orthophosphoric acid 6 4.2 Determination of total cyanide content .6 5 Reagents .6 5.1 Reagents for liberation and absorption of cyanide .6 5.2 Reagents f
5、or the photometric determination of cyanide .7 5.3 Reagents for the titrimetric determination of cyanide .7 6 Apparatus .8 7 Sample preservation and preparation .9 7.1 Sample preservation .9 7.2 Sample preparation .9 8 Direct liberation using orthophosphoric acid 10 8.1 Procedure 10 8.2 Blank test .
6、 10 9 Determination of cyanide Photometric method 11 9.1 Applicability . 11 9.2 Procedure 11 9.3 Preparation of the calibration graph . 11 9.4 Calculation . 11 10 Determination of cyanide Titrimetric method using an indicator . 12 10.1 Applicability . 12 10.2 Procedure 12 10.3 Calculation . 13 11 Ex
7、pression of results . 13 12 Precision 14 13 Test report . 14 Annex A (informative) Precision data 15 Annex B (informative) Extraction with sodium hydroxide solution and subsequent liberation using orthophosphoric acid 16 Annex C (informative) Comparison of the direct liberation of total cyanide and
8、sodium hydroxide extraction with subsequent liberation . 19 Bibliography . 20 2 DIN ISO 11262:2012-04 National foreword This standard has been prepared by Technical Committee ISO/TC 190 “Soil quality”, Subcommittee SC 3 “Chemical methods and soil characteristics”. The responsible German body involve
9、d in its preparation was the Normenausschuss Wasserwesen (Water Practice Standards Committee), Working Committee NA 119-01-02-02 UA Chemische und physikalische Verfahren. The DIN Standards corresponding to the International Standards referred to in this document are as follows: ISO 3696 DIN ISO 3696
10、 ISO 5725-2 DIN ISO 5725-2 ISO 9297 DIN 38405-1 (mod.) ISO 11464 DIN 19747 ISO 11465 DIN ISO 11465 ISO 14507 DIN ISO 14507 ISO 17380 DIN ISO 17380 National Annex NA (informative) Bibliography DIN 38405-1, German standard methods for the examination of water, waste water and sludge Anions (group D) D
11、etermination of chloride ions (D 1) DIN 19747, Investigation of solids Pretreatment, preparation and processing of samples for chemical, biological and physical investigations DIN ISO 3696, Water for analytical laboratory use Specification and test methods DIN ISO 5725-2, Accuracy (trueness and prec
12、ision) of measurement methods and results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method DIN ISO 11465, Soil quality Determination of dry matter and water content on a mass basis Gravimetric method DIN ISO 14507, Soil quality Pretreat
13、ment of samples for determination of organic contaminants DIN ISO 17380, Soil quality Determination of total cyanide and easily released cyanide Continuous-flow analysis method 3 DIN ISO 11262:2012-04 IntroductionCyanides form simple salts with alkali earth cations and ionic complexes of varying str
14、engths with numerous metal cations; the stability of these compounds is dependent on the cation and on the pH. Cyanide forms complexes with gold, mercury, cobalt and iron that are very stable even under mildly acidic conditions. Metal cyanide complexes also form salt-type compounds with alkali or he
15、avy-metal cations, such as potassium ferrocyanide (K4Fe(CN)6) or copper ferrocyanide (Cu2Fe(CN)6). Cyanides can be present in soil both as cyanide ions and as complex cyanides.Determination of cyanides can be carried out under different conditions. When using mild acidic conditions (e.g. pH = 4), on
16、ly so-called “easily liberatable cyanides” (also known as “weak-acid dissiciable cyanides”) are measured. Under strong acidic conditions (e.g. pH = 1), all cyanides (both easily liberatable and complex cyanides) can be determined, these are called “total cyanides”.A number of studies in soil samples
17、 have demonstrated that it is impossible to obtain reliable results for easily liberatable cyanide (ELC) using a manual ELC cyanide extraction/reflux method. Consequently, this revised International Standard does not include an ELC method.NOTE ISO 17380gives details of both an automated ELC method a
18、nd a total cyanide method.This International Standard specifies manual methods for the determination of total cyanide only. An alternative method for alkaline extraction prior to liberation using orthophosphoric acid is described in Annex B.Soil quality Determination of total cyanide4 DIN ISO 11262:
19、2012-04 WARNING Hydrogen cyanide and its salts are toxic. Therefore, care shall be exercised when manipulating cyanide-contaminated samples. Volatile hydrogen cyanide (with a smell of bitter almonds) is released from acidified solutions containing cyanide salts. As a minimum, all work shall be carri
20、ed out in a fume hood and suitable plastic gloves shall be worn when handling contaminated samples.Analytical wastes containing cyanides shall be placed in a special container with a lid, in the laboratory, for temporary storage. This container shall be clearly marked with labels such as “toxic wast
21、e” or “cyanides”. Periodically, the container shall be emptied and the wastes containing cyanides disposed of as “special waste” by an appropriate waste-management contractor.1 ScopeThis International Standard is applicable to as-received (field-moist) samples and specifies two different procedures
22、for the liberation of cyanide from the soil: direct liberation of hydrogen cyanide using orthophosphoric acid (normative); extraction with sodium hydroxide solution and subsequent liberation using orthophosphoric acid (informative, see Annex B).The liberated cyanide is determined either by a photome
23、tric method or a titrimetric method using an indicator.The method is applicable to all types of soil.Under the conditions specified in this International Standard, the lower limit of application is 0,5 mg/kg of total cyanide (expressed on the as-received basis) for photometric determination and 10 m
24、g/kg for titrimetric determination.NOTE Using the alkaline extraction followed by liberation using phosphoric acid, the lower limit of application is 1 mg/kg of total cyanide (expressed on the as-received basis) for photometric determination and 30 mg/kg for titrimetric determination.2 Normative ref
25、erencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 3696:1987, Water for analytical laborat
26、ory use Specification and test methodsISO 9297, Water quality Determination of chloride Silver nitrate titration with chromate indicator (Mohrs method)ISO 11464, Soil quality Pretreatment of samples for physico-chemical analysisISO 11465, Soil quality Determination of dry matter and water content on
27、 a mass basis Gravimetric methodISO 14507, Soil quality Pretreatment of samples for determination of organic contaminants3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.5 3.1total cyanideall compounds which form hydrogen cyanide under the condition
28、s of this methodDIN ISO 11262:2012-04 3.2recovery factorFrcrecovery factor (Frc) of the liberation apparatus for total cyanide is the fractional recovery of a mid-range standard containing potassium hexacyanoferrate(III) carried through the whole procedure against an equivalent calibration standard
29、of potassium cyanide not carried through the liberation stage, but only through the final detection stage of the method (mfound/mknown)4 Principle4.1 Direct liberation of hydrogen cyanide using orthophosphoric acidThe field-moist sample is homogenized and pretreated in accordance with ISO 14507, rem
30、oving visible coarse constituents. It is then treated with orthophosphoric acid and the liberated hydrogen cyanide is transported by an airflow and absorbed into 1 mol/l sodium hydroxide. Tin(II) and copper(II) salts are added to suppress the interference from sulfur compounds and catalyse the decom
31、position of complex cyanides during the liberation process.4.2 Determination of total cyanide contentCyanide ion in the sodium hydroxide absorber solutions is determined either photometrically (see Clause 9) by a procedure based on the reaction of cyanide with chloramine-T with the formation of cyan
32、ogen chloride; this reacts with pyridine-4-carboxylic acid and 1,3-dimethylbarbituric acid to form a coloured complex, the absorbance of which is measured at 606 nm, or titrimetrically (see Clause 10) by a titrimetric procedure involving titration with silver nitrate. When in excess relative to the
33、Ag (CN)2- ion, silver ions form a red-coloured complex with the end-point indicator, 5-(4-dimethylaminobenzylidene)rhodanine.5 ReagentsAll reagents shall be of recognized analytical grade and the water used shall conform to grade 2 of ISO 3696:1987. All reagents are stable for at least 3 months unle
34、ss stated otherwise.5.1 Reagents for liberation and absorption of cyanide5.1.1 Orthophosphoric acid, w(H3PO4) = 85 % (mass fraction), r = 1,69 g/ml.5.1.2 Sodium hydroxide solution, c(NaOH) = 1 mol/l.Dissolve 40 g of NaOH in water and dilute with water to 1 000 ml, or use commercially available solut
35、ions. Store in a polyethylene bottle.5.1.3 Hydrochloric acid solution, c(HCl) = 1 mol/l.5.1.4 Tin(II) chloride solution.Dissolve 50 g of tin(II) chloride dihydrate (SnCl22H2O) in 40 ml of the hydrochloric acid solution (5.1.3) and dilute with water to 100 ml. Prepare a fresh solution daily.6 Dilute
36、98,6 gN1)of concentrated hydrochloric acid (37 %, 1,18 g/ml) with water to 1 000 ml or use commercially available solutions. N1) National footnote: For a specific gravity of = 1,18 g/ml, this value is equivalent to a volume of 83 ml. DIN ISO 11262:2012-04 5.1.5 Copper(II) sulfate solution.Dissolve 2
37、00 g of copper(II) sulfate pentahydrate (CuSO45H2O) in water and dilute with water to 1 000 ml.5.2 Reagents for the photometric determination of cyanide5.2.1 Sodium hydroxide solution, c(NaOH) = 0,8 mol/l.Dissolve 32 g of NaOH in water and dilute with water to 1 000 ml. Store in a polyethylene bottl
38、e.5.2.2 Glacial acetic acid, 20 % (volume fraction).Dilute 100 ml of glacial acetic acid (r = 1,049 g/ml) to 500 ml in a measuring cylinder with water.NOTE 100 % glacial acetic acid (r = 1,049 g/ml), as well as 96 % glacial acetic acid (r = 1,06 g/ml), are commercially available.5.2.3 N-Chloro-4-met
39、hylbenzenesulfonamide sodium salt (chloramine-T) solution.Dissolve 0,5 g of chloramine-T trihydrate C7H7ClNO2SNa(3H2O) in water in a 50 ml volumetric flask and dilute to the mark. Prepare a fresh solution daily.5.2.4 Colour reagent.Dilute 7,0 g of sodium hydroxide (NaOH) in 500 ml of water. Add 16,8
40、 g of 1,3-dimethylbarbituric acid (C6H8O3N2), and 13,6 g of pyridine-4-carboxylic acid (isonicotinic acid) (C6H5NO2), and dilute to 1 000 ml with water. Mix well for 1 h at 30 C and then filter (pore size approximately 8 m) through a pleated filter. This solution can be kept for at least 1 week, pro
41、vided it is stored below 10 C in the dark, and filtered through another pleated filter (pore size approximately 8 m) before use.5.2.5 Potassium cyanide stock solution, corresponding to 100 mg/l of cyanide ion.Dissolve 250 mg of potassium cyanide (KCN) in the 0,8 mol/l sodium hydroxide solution (5.2.
42、1) and dilute with the same sodium hydroxide solution to 1 000 ml in a volumetric flask. Standardize this solution by titration with the 0,01 mol/l silver nitrate solution (5.3.1), once each day if determinations are carried out (see Clause 9). Commercially available stock solutions may also be used
43、. Store in the dark and at a temperature below 10 C.5.2.6 Potassium cyanide standard solution, corresponding to 10 mg/l of cyanide ion.Dilute 10 ml of stock solution (5.2.5) to 100 ml in a volumetric flask using the 0,8 mol/l sodium hydroxide solution (5.2.1). Prepare daily.5.2.7 Paranitrophenol (0,
44、1 % m/V) in ethanol.Dissolve 0,1 g of paranitrophenol in 100 ml of ethanol.5.3 Reagents for the titrimetric determination of cyanide5.3.1 Silver nitrate solution, c(AgNO3) = 0,01 mol/l.Dissolve 1,699 g of silver nitrate in approximately 400 ml of water and dilute to 1 000 ml in a volumetric flask wi
45、th water. Check the actual concentration of the 0,01 mol/l silver nitrate by titration with sodium chloride in accordance with ISO 9297 on a two-weekly basis. Store this solution in the dark.5.3.2 Silver nitrate solution, c(AgNO3) = 0,001 mol/l.Prepare daily from the 0,01 mol/l silver nitrate soluti
46、on (5.3.1). Add 25,00 ml of 0,01 mol/l silver nitrate solution to a 250 ml volumetric flask and dilute to 250 ml with water. Cover the flask with aluminium foil to exclude light.7 DIN ISO 11262:2012-04 5.3.3 Indicator solution.Dissolve 0,02 g of 5-(4-dimethylaminobenzylidene) rhodanine in acetone an
47、d dilute with acetone to 100 ml. This solution is stable for up to 1 week if kept in the dark at ambient temperature.6 ApparatusUsual laboratory equipment and, in particular, the following:6.1 Apparatus for the liberation and absorption of hydrogen cyanide.Use the apparatus shown in Figure 1. The ro
48、und-bottomed flask (9) shall be triple-necked, have a capacity of at least 500 ml and have standard conical joints (for example 29/32 central neck, 19/24 side necks). A water-cooled Liebig condenser (3) (for example 16 cm long and 30 mm in outer diameter); a 50 ml dropping funnel (5) and an air-inlet tube (7) are fitted. The connection to the absorption vessel (2) (for example 20 cm long and 2,5 cm in inner diameter) is via a transfer line (1). Standard joints are fitted to this tube to enable connec
