Tiêu chuẩn iso 17075 2 2017

© ISO 2017 Leather — Chemical determination of chromium(VI) content in leather — Part 2 Chromatographic method Cuir — Détermination chimique de la teneur en chrome(VI) du cuir — Partie 2 Méthode chrom[.]

Leather — Chemical determination of

Part 2:

Cuir — Déte mination chimique de la teneur en chrome VI)du cuir —

Partie 2: Méth de chromato ra hique

COPYRIGHT PROTECTED DOCUMENT

© ISO 2017, P blshed in Sw itz rlan

A ll rig hts r eserved Unles otherw ise spe ified, nopar of this p blc tion ma y be r epr od c d or utilz d otherw ise in an form

or b an me ns, ele tr onic or me hanic l, inclu in p oto opying , or postin on the internet or an intranet , w ithout prior

written permis ion Permis ion c n be req esed from either ISO at the ad r es below or ISO’s member bod y in the c u try of

IULT CS IUC 18-2:2017(E)

F reword i v

1 Sc ope 1

2 Nor mati ve r eferenc es 1

3 Terms an definitions 1

4 Principle 2

5 Chemicals 2

6 A pparatus and mater ials 2

7 Proc ed re .3

7.1 Sampl ng an pr eparation of samples

3 7.2 Pr eparation of analytical solution 3

7.3 Chromatog raphic con itions 4

7.4 Calbration 4

7.5 Dete mination of the r eco e y rate 5

8 Calculation and ex pr es io of r esults 5

8.1 Calculation of chr omium(VI) content 5

8.2 Re o e y rate (ac or ding to 7.5) 6

8.3 Ex pr es ion of r esult 6

9 Test rep r t 6

A nne x A (informative)Ac curacy

7 A nne x B (informative)Chromatog raphic c onditions for dir ect detection metho 9

A nne x C (informative) C romatog raphic c onditio s for metho with post-column r eactio 12

A nne x D (informative) C mpar ison betwe n the c olorimetr ic meth d (ISO 1707 -1) and the io ic chr omatog raph y meth d (ISO 1707 -2) .16

ISO (he Int ernational Org nization for Stan ardization) is a worldwidefede ation of national s an ards

b dies (ISO membe b dies) The work of pr p ring Int ernational Stan ards is normaly car ied out

through ISO t ech ical committ ees Each membe b dy int er st ed in a subje t for w hich a t ech ical

committ ee has be n es a lshed has the right t o be r pr sent ed on that committ ee Int ernational

org nizations, g ove nmental an non-g ove nmental, in laison with ISO, also take part in the work

ISO cola orat es closely with the Int ernational Ele trot ech ical C mmis ion (IEC) on al matt ers of

ele trot ech ical s an ardization

The proc d r s used t o develo this document an those int en ed for it furthe maint enanc ar

desc ibed in the ISO/IEC Dir ctives, Part 1 In p rticular the dife ent a pro al c it eria ne ded for the

dife ent ty es of ISO document should be not ed This document was draft ed in ac ordanc with the

edit orial rules of the ISO/IEC Dir ctives, Part 2 ( e www iso org dir ctives)

A tt ention is drawn t o the p s ibi ity that some of the element of this document ma be the subje t of

p t ent right ISO shal not be held r sponsible for identifying any or al such p t ent right Detais of

any p t ent right identified d ring the develo ment of the document wi be in the Introd ction an / r

on the ISO ls of p t ent de larations r c ived ( e www iso org p t ent )

Any trade name used in this document is information given for the convenienc of use s an does not

cons itut e an en orsement

For an ex lanation on the meaning of ISO spe ific t erms an ex r s ions r lated t o conformity as es ment,

as wel as information a out ISO’s adhe enc to the Wor ld Trade Org nization (WTO) principles in the

Te h ical Bar ie s to Trade (TBT) se the folowing URL: www iso org iso/ for word html

ISO 1 0 5- 2 was pr par d b the Chemical Tes C mmis ion of the Int ernational Union of Leathe

Te hnolo is s and Chemis s Societies (IUC Commis ion, IULTCS) in cola oration with the Euro ean

Committ ee for Stan ardization (CEN) Te hnical Committ ee CEN /TC 2 9, Leathe , the se r tariat of

w hich is held b UNI, in ac ordanc with the Agr ement on t ech ical co pe ation betwe n ISO an CEN

(V ien a Agr ement)

IULTCS, originaly formed in 1 9 , is a world-wide org nization of profes ional leathe societies t o

furthe the adv nc ment of leathe scienc an t ech olo y IULTCS has thr e Commis ions, w hich

ar r sp nsible for es a l shing int ernational methods for the sampl ng an t es ing of leathe ISO

r co niz s IULTCS as an int ernational s an ardizing b dy for the pr p ration of t es methods for

leathe

This firs edition of ISO 1 0 5- 2, t og ethe with ISO 1 0 5-1, canc ls an r plac s ISO 1 0 5:2 0 , w hich

has be n t ech ical y r vised

The main chang es comp r d t o ISO 1 0 5:2 0 ar as folow s:

— thechromat ogra hic analytical t echniq e has be n ad ed;

— thesample pr paration has be n r vised;

— me hanical shaking in 7.1an 7.2 has be n r vised

A l s of al p rt in theISO 1 0 5 se ies can befou d on the ISO websit e

This document spe if ies a method for det ermining chromium(VI) in solutions leached from leathe

un e defined con itions The method desc ibed is suita le t o q antify the chromium(VI) cont ent in

leathe s down t o 3 mg kg

This document is a plca le t o al leathe ty es

The r sult o tained from this method ar s rictly depen ent on the extraction con itions R esult

o tained b using othe extraction proc d r s (extraction solution, pH, extraction time, et c ) ar not

comp ra le with the r sult prod c d b the proc d r desc ibed in thisdocument

If a leathe sample is t est ed with b th ISO 1 0 5-1 an this document, the r sult o tained with this

document ar conside ed as the r fe enc The adv ntag e of the method desc ibed in this document is

that the e ar no int erfe enc s from the colour of the extract Neve theles , int erla orat ory trials do

not how significant dife enc s ( e An ex D) and the r sult ar comp ra le betwe n b th methods

2 Normati ve r eferences

The folowing document ar r fe r d t o in the t ext in such a wa that some or al of their cont ent

cons itut es r q ir ment of this document F or dat ed r fe enc s, only the edition cit ed a ples F or

un at ed r fe enc s, the lat es edition of the r fe enc d document ( inclu ing any amen ment ) a ples

ISO 241 , Leathe — Chemic al,p ys ic al a d mecha ic al a d f s tnes s tes ts — S mpln loc atio

ISO 3 9 , Wate fr a aly tic al la orator y use — S ec ific atio a d tes t meth ds

ISO 4044:2 1 , Leathe — Chemic al tes ts — Prep ratio o chemic al tes t s amples

ISO 46 4, Leathe — Chemic al tes ts — Dete min tio o v latie matte

3 Terms and definitions

F or the purposes of this document, the folowing t ermsand definitions a ply

ISO an IEC maintain t erminolo ical data ases for use in s an ardization at the folowing ad r s es:

— ISO Onlne brow sing plat orm:a ai a le at ht p:/ www iso org o p

— IECEle tro edia: a aia le at ht p:/ www ele tro edia org

3.1

chromium(VI co tent

amount of chromium(VI) in leathe dete mined af e extraction with an aq eous salt solution at

pH 7,0 to 8,0

Note 1 t o entry: T e chromium(VI content is reported as chromium(VI in mil igrams per kilo ram (mg kg),

e pres ed as the dry mas of the sample

4 Principle

Extracta le chromium(VI) is leached from the sample in phosphat e bufe at pH7,0 t o 8,0 An alq ot of

the f ilt er d extract is analysed for Cr(VI) using ion-ex chang e chromat ogra hy with UV- VIS det ection

4

·3H

2

O in 1 0 0 ml wat er (5.7), adjust ed

t o pH 8,0 ± 0,1 with phosphoric acid (5.2) Deg s this solution with eithe arg on or nitrog en (5.6) or

ultrasonic b th

Stan ard practic is t o make upa fr sh solution each da Howeve , the solution can be kept for up t o one

we k in a r frig erat or at (4 ± 3) °C but shal be warmed t o ro m t empe atur an deg s ed prior t o use

5.2 Phosph r ic acid solution

7 0 ml o-phosphoric acid, ρ = 1,7 g ml, made up t o 1 0 0 ml with wat er (5.7)

Firs ad a pro imat ely 2 0 ml of deionised wat er (5.7) t o a 1 0 0 ml volumetric flask, then ad the

7 0 ml of o-phosphoric acid an diut e t o the mark with deionised wat er

5.3 Potas ium dichromate (K

2

Cr O

7), dried for (1 ± 2) h at (1 2 ± 2) °C

5.4 C romium(VI) stock solutio

Dis olve 2,8 9 g potas ium dichromat e (K

2Cr

2O

7) (5.3) in wat er (5.7) in a v lumetric flask an make

up t o 1 0 0 ml with wat er (5.7) One mi i tr of this solution contains 1 mg of chromium

A st ock solution at this conc ntration level of hex v lent chromium is an alt ernative a aia le

comme cialy

5.5 C romium(VI) standard solutio

Pipett e 1 ml of solution (5.4) int o a 1 0 0ml v lumetric flask an make up t o the mark with extraction

solution (5.1) One mi l itr of this solution contains 1 μg of chromium

The solution can be kept for up t o one we k in a r frig erat or at (4 ± 3) °C but shal be warmed t o ro m

t empe atur prior t o use

A st ock solution of hex v lent chromium at this conc ntration level is an alt ernative a aia le

comme cialy

5.6 A r g on or nitr og en, ox yg en-fr ee

Pr fe enc should be given t o arg on as an ine t g s inst ead of nitrog en be ause arg on has a highe

spe ific mas than air

5.7 Disti led or deio ised water, Gr ade 3 q alty as spe ified in ISO 3 9

6 A pparatus and materials

Usual la orat ory eq ipment and, in p rticular, the fol owing

6.1 Suitable mechanical or bital shaker, (1 0 ± 1 ) min

−

6.2 C nical flask, of ca acity 2 0 ml, with s o pe

6.3 Aeration tu e an flow meter, suita lefor a flow rateof (5 ± 10) ml/min

6.4 Membrane fiter , 0,45 µm p r e siz [p lytetrafluor oeth ylene (P FE)or p ly mide 6 ]

6.5 C mmo laborator y glas ware and pipet es

6.6 Io -e xchang e chromatog raph, with UV detector or high per for manc e lquid chromatog raph

(HPL C) with anio -e xchang e c olumn and UV detector It is r ecommen ed a photo diode arra y

dete tor (DA D)

6.7 A nal ytical balanc e, ca a le of weighing to 0,1 mg

6.8 Suitable vials for HPL

6.9 Shar p cut ing to l or blade, suita le for cutting the leathe into 3 mm to 5 mm pie es

7.1 S mpl ng and pr eparation of samples

If pos ible, sample in ac ordanc with ISO 241 If sampl ng in ac ordanc with ISO 241 is not pos ible

(e.g leathe s from finished prod ct lke shoes, g rment ), detai s a out amplng shal be given in the

t es r p rt

Pr p r the leathe sample b cut ing (6 9) int o smal pie es ac ording t o the method spe ified in

ISO 4044:2 1 , 6.3

7.2 Preparation of anal ytical solution

Weigh (6.7) a pro imat ely (2 ± 0,1)g of leathe pie es t o the near s 0,0 1 g Pipett e 1 0 ml of deg s ed

solution (5.1) int o a 2 0 ml conical flask (6.2) Displac o y g en b p s ing o y g en-fr e arg on (or

nitrog en) (5.6) int o the flask for 5 min with a v lume flow of (5 ± 1 ) ml/min R emo e the ae ation

tube (6.3), ad the leathe an closethe flask with a st op e R ecord the extract v lume as V

0

Shake the conical flask with the leathe pie es for 3 h ± 5 min on a me hanical orbital shaker at

(1 0 ± 1 )min

−

(6.1) at ro m t empe atur t o extract he chromium(VI)

Shake the suspension in a smo th cir ular mo ement t o keep the leathe pie es from ad e ing t o the

wal of the flask an a oid shaking fast er than spe ified

Immediat ely aft er completing the 3 h of extraction, filt er the cont ent of the conical flask through

a membrane filt er int o a glas or plas ic ves el with l d Che k the pH of the solution The pH of the

solution shal be betwe n 7,0 an 8,0 If the pH of the solution is not within this rang e, s art the complet e

proc d r a ain

Conside using a smale sample mas , if the pH is not betwe n 7,0 an 8,0 In this case, the q antif ication

l mit wi be inc eased

Trans e an alq ot of the filt er d extract int o a vial (6.8)

IULT CS IUC 18-2:2017(E)

7.3 Chromatog raphic c onditions

Det ermination of chromium(VI) is pe formed using the ion chromat ogra hic t ech iq e As the

ins rumental eq ipment of the la orat ories ma v ry, no spe ific a plca le ins ructions can be

pro ided for analy sis Howeve , the o e ating paramet ers an ex mples ofthe ion chromat ogra hic

analysis for chromium(VI) l st ed in Annex es B an C ha e be n suc es fuly t est ed an used Annex B

det ermines chromium(VI) b dir ct det ection of chromat e peak at 3 2 nm An ex C det ermines

chromium(VI) aft er a pos -column r action with 1,5-dipheny lcarb zide b measuring the a sorption

peak at 540 nm

The method used should be ve ified using the r co e y rat e det ermination (7.5) an the r sult

o se ved should be in the rang e as lst ed in An ex A

R ecord the inje tion v lume as V

M

an r cord the ar a of the chromat e peak as A

7.4 Cal bration

The cont ent of chromium(VI) in leathe is det ermined with an ext ernal s an ard calbration

Pr p r calbration solutions from the s andard solution (5.5) The chromium(VI) conc ntration in

these solutions should co e the ex e t ed rang e of measur ment

Plot a suita le cal bration curve b using at leas five s an ards, within the rang e 1 ml t o 2 ml of

s an ard solution (5.5) Pipett e the given v lumes of s an ard solution (5.5) int o 2 ml v lumetric

flasks Make up t o v lume with the extraction solution (5.1), mix wel an trans e a suita le alq ot

v lume int o a vial (6.8)

Pr p r calbration levels as spe if ied in Ta le 1

Table 1 — Calbratio levels preparation

Trans e an alq ot t o a suita le vial (6.8) cor esp n ing for the chromat ogra hy sy st em (6.6)

Inje t the s an ards in thechromat ogra hic sy st em (6.6) Introd c the same volume for each s an ard

It isr commen ed t o inje t eq al v lume for samples R ecord the v lume inje t ed as V

c

in µl

Plot the chromium(VI) conc ntrations in mic o rams of Cr pe mi l ltr (μg ml) a ains the

measur d ar as of the peaks of chromate Plot the chromium(VI) conc ntration on the x-a is an the

ar a on the y-a is

7.5 Determination of the rec over y rate

The det ermination of the r co e y rat e is important t o pro ide information a out pos ible matrix

efe t w hich can influenc the r sult

Spike an alq ot of the solution o tained in 7.2 with a suita le v lume of chromium(VI) solution t o

inc ease the chromium(VI) conc ntration b 1 mg kg Inje t the same v lume of this solution as the

v lume inje t ed in the cal bration (r cording the ar a as A

s

Spike an al q ot of the extraction solution (5.1) (he same v lume as that taken befor of the solution

o tained in 7.2) with a suita le v lume of chromium(VI) solution t o inc ease the chromium(VI)

conc ntration b 1 mg kg, so that the final v lume of this solution is the same as that of the a o e

spiked solution with chromium(VI) solution Inje t the same v lume of this solution as the v lume

inje t ed in the calbration (r cording the ar a as A

s)

The ar a of the chromate peak of these solutions shal be within the range of the calbration curv e,

othe wise r peat the proc d r using a smale al q ot The r covery rate shal be betw een 8 %

an 12 %

NOTE If the ad ed chromium(VI is not detected, this is an in ication that the le ther contains red cing

a ents T is le ds to the conclusion that his le ther has no chromium(VI content (b low detection limit)

8 Calculation and ex pres ion ofresults

8.1 Calculation of chr omium(VI) c ontent

A is the ar a of the peak of chromat e in the chromat ogram of the extract of the sample;

F is the gradient of calbration curve (y/ x), ex r s ed in mi i tr s pe mic o ram (ml/μg);

b is the int er ept of cal bration curve (y/x);

m is the mas of the leathe sampletaken, ex r s ed in grams (g);

R esult ar b sed on dry matt er.

is the area of chromate peak of sample solution after ad ing chromium(VI) as determined in (7.5);

A is the ar a of chromat e peak in the original sampleas det ermined in (7.3);

The chromium(VI)cont ent is given in mi igrams pe ki o ram (mg kg) roun ed t o the near s 0,1 mg

The cont ent is b sed on dry matt er The v latie matt er, det ermined ac ording t o ISO 46 4, is given in

pe c nt ( % )rou ded t o the near s 0,1 %

The extraction matrix for leathe is complex an r sult below 3 mg kg show larg e v riations an ha e

l mit ed r la i ity;the efor the q antif ication l mit shal be 3 mg kg

9 Test repor t

The t es r p rt shal inclu e the fol owing information:

a) thechromium(VI) cont ent (s)o tained from 8.1t o the near s 0,1 mg kg;

b) a r fe enc t o this document, i.e ISO 1 0 5- 2:2 17 ;

c) a desc iption of the sample t est ed an detais a out ampl ng (7.1), if ne es ary;

d) a brief desc iption of the chromat ogra hic t ech iq e ( i.e dir ct det ection t ech iq e or w hethe a

pos -column r action was used);

e) thev latie matt er of the leathe in pe c nt (% ) t o the near s 0,1 %;

f) ther co e y rat e in pe c nt (% );

g) detai s of any deviationsfrom the proc d r

A nne x A

Ac curacy

R esult o tained from an int ernational int erla orat ory trial car ied out in Ju e 2 1 for two ty es of

leathe ar summariz d in Ta le A.1, Ta le A.2 an Ta le A.3

Table A.1 — Results for o e type of le the (Le ther A)

Unc r ainty:± 0,9 bein k = 2,3 ( P 95 %)

Table A.2 — Results for one ty e of le the (Le ther B)