Tiêu chuẩn iso 17075 1 2017

© ISO 2017 Leather — Chemical determination of chromium(VI) content in leather — Part 1 Colorimetric method Cuir — Détermination chimique de la teneur en chrome(VI) du cuir — Partie 1 Méthode colorimé[.]

Leather — Chemical determination of

Part 1:

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

Partie 1: Méth de colorimétrique

Fir t edition

2 17-0

Refer ence n mb r

ISO 17075-1:2 17(E)

IUL CS IUC 1 -1:2 17(E)

COPYRIGHT PROTECTED DOCUMENT

© ISO 2017, P blshed in Sw itz rlan

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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

the r eq eser

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C de Blan on et 8 • C 4 1

CH-1 14 Vernier, Geneva, Switzerlan

Tel + 12 7 9 011

Fax 412 7 9 0 4

IULT CS IUC 18-1:2017(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 3

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 Dete mination of chr omium(VI) in the solution o tained fr om the ex tr action pr oc d re 4 7.4 Blan solution 4

7.5 Calbration 5

7.6 Dete mination of the r eco e y rate 5

7.6.1 Influenc of the matrix 5

7.6.2 Influenc of the SPE mate ial (6.9) 5

8 Calculation and ex pr es io of r esults 6

8.1 Calculation of chr omium(VI) content 6

8.2 Re o e y rate (ac or ding to 7.6.1) 6

8.3 Ex pr es ion of results 7

9 Test rep r t 7

A nne x A (informative)Sold phase e x tractio (SPE) mater ial 8

A nne x B (informative)Ac curacy 9

A nne x C (informative) C mpar ison betwe n the c olorimetr ic method (ISO 1707 -1) and the io ic chr omatog raph y meth d (ISO 1707 -2) .11

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 terms an ex r s ions r lat ed to 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 5-1 was pr p r d b the Chemical Tes Commis 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 5-1, t og ethe with ISO 1 0 5- 2, 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:

— thesample pr paration has be n r vised;

— me hanical shaking in 7.1, 7.2 an 7.3 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

IULT CS IUC 18-1:2017(E)

Part 1:

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 this document an ISO 1 0 5- 2, the r sult o tained with

ISO 1 0 5- 2 ar conside ed as the r fe enc The adv ntag e of the method desc ibed in ISO 1 0 5- 2 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 C) an 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 pH 7,0 t o 8,0 an

co-extract ed colour d subs anc s w hich influenc the det ection ar r mo ed b sold phase extraction if

ne es ary The chromium(VI) in solution o idiz s 1,5-dipheny lcarb zide t o 1,5-dipheny lcarb zone t o

give a r d/ iolet complex with chromium w hich can be q antif ied phot ometricaly at 540 nm

Al r ag ent used shal ha e at leas analytical grade purity

5.1 Ex tractio solution

Dis olve 2 ,8 g dip tas ium hydrog enphosphat e, K

2

HPO

4

⋅3H

2

O, in 1 0 0 ml wat er, adjust ed t o

pH 8,0 ± 0,1 with phosphoric acid (5.3) 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 Dip enylcar bazide (DPC)solution

Dis olve 1,0 g 1,5-dipheny lcarb zide, CO(NHNHC

6 H

5 )

2 , in 1 0 ml ac t one, (CH

3 )

2

CO, an acidif ied with

one dro of glacial ac tic acid, CH

3 COOH

Thesolution should be kept in a brown glas b t le The shelf lfe is upt o 14 day s at 4 °C

5.3 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 deionised 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 v lumetric flask, then ad the

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

5.4 C romium(VI) stock solutio

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

2 Cr

2 O

7 ) (5.8) in wat er in a volumetric flask an make up t o

1 0 0 ml with wat er 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 at this conc ntration level of hex v lent chromium 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 Distiled or deio ised water, Grade 3 q alty as spe ified in ISO 3 9

5.8 P otas ium dichr omate (K

2

Cr

2 O

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

5.9 Methanol, HPL g rade

6 A pparatus and materials

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

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 lytetr afluoroeth ylene (P FE)or p ly mide 6 ]

6.5 Volumetr ic flasks, of ca acity 2 ml, 1 0 ml an 1 00 ml

6.6 Pipet es, v rious nominal v lumes

6.7 Spectr ophotometer or fiter photometer, wa veleng th 540 nm

6.8 Photometr ic c el , q artz, 40 mm leng th or any othe suitable c l leng th

6.9 Glas or pol ypr op lene cartridg es filed with a suitable sold phase e x tractio (SPE) mater ial,

e.g reve sed phase (RP)C1 or a suita le activ ted mag nesium si cate, se A nnex A for examples of SP

mate ials

6.10 Sold p ase e x traction (SPE) system, with v cu m devic or solvent-r esistant medical syring e

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

6.12 A nal ytical balanc e, ca a le of weighing to the neares 0,1 mg

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 (6.1 ) int o smal pie es ac ording t o the method spe if ied in

ISO 4044:2 1 , 6.3

7.2 Preparation of anal ytical solution

Weigh (6.1 ) 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 yg en b p s ing o yg en-fr e arg on

IULT CS IUC 18-1:2017(E)

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

tube (6.3), ad the leathe pie es 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 (6.1) at

(1 0 ± 1 ) min

−

t o extract the chromium(VI)

Shake the flask 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 if ied

Immediat ely aft er completing 3h 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 ld Che k the pH of the solution The pH of the solution shal be

betwe n 7,0 an 8,0 If the pHof the solution is not within this rang e, s art the complete proc d r a ain

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

l mit wi be inc eased

7.3 Deter mination of chromium(VI) in the solution obtained from the e x traction

proc edure

If the leathe sample is colour d, it is l kely some colour d subs anc s, e.g dyes, wi l ha e be n

co-extract ed These can influenc the det ection of chromium(VI) The extract ed colorant can be r mo ed

b p s ing the extraction solution (7.2) through a cartridg e containing a suita le sol d phase extraction

mat erial (6 9), se An ex A for ex mples

Pr -tr at the SP cartridg es (6 9) in the folowing wa :

a) flush the cartridg e (6 9) f irs with 5 ml methanol (5 9),

b) aft erwards with 5 ml dis i ed wat er (5.7) an

c) dir ctly aft erwards with 1 ml of extraction solution (5.1)

Do not dry the cartridg es (6 9) d ring or aft er the pr -tr atment

From the solution o tained in 7.2, take 1 ml (V

1 )and trans e this q antitatively through the cartridg e

(6 9) on an SP sy st em with a v cu m devic or syring e (6.1 ) C le t the eluat e in a 2 ml v lumetric

flask (6.5) Flush the cartridg e with 1 ml extraction solution (5.1) int o the 2 ml flask Make up the

flask t o volume (V

2 ) with extraction solution (5.1) Mark thissolution as S

1

Pipett e (6.6) 1 ml (V

3 ) of solution S

1 int o a 2 ml v lumetric flask Diut e the solution t o 3 4 of the

flask’s v lume with extraction solution (5.1) Ad 0,5 ml of phosphoric acid solution (5.3) an aft erwards

0,5 ml of dipheny lcarb zide solution (5.2) Make up the flask t o v lume (V

4 ) with extraction solution

(5.1) and mix wel

Let s an for at leas 1 min ± 5 min Measur the a sorb nc of the solution at 540 nm in a 40 mm c l

(6.8) a ains the blank solution (7.4) R ecord the a sorbanc o tained as A

1

F or each ru , pipett e anothe 1 ml alq ot of solution S

1 int o a 2 ml v lumetric flask an tr at it

as desc ibed a ove, but without the ad ition of the dipheny lcarb zide solution (5.2) Measur the

a sorb nc of this solution in the same wa as befor an r cord it as A

2

7.4 Blank solution

Fi l a 2 ml v lumetric flask thr e q art ersful with extraction solution (5.1), ad 0,5 ml of phosphoric

acid (5.3) an 0,5 ml of dipheny lcarb zide solution (5.2) an make up t o the mark with extraction

solution (5.1) an mix wel Pr p r this solution daiy an st or it in the dark Tr at he blan solution

in the same wa as the analytical solution, ex clu ing thesold phase extraction

7.5 Cal bration

Pr p r calbrating solutions from the s an ard solution (5.5) The chromium conc ntration in these

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

Pr p r the calbration solutions in 2 ml v lumetric flasks(6.5)

Plot a suita le cal bration curve b using at leas six s an ards, within the rang e 0,5 ml t o 1 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 Ad 0,5 ml of phosphoric acid (5.3) an 0,5 ml dipheny lcarb zide solution (5.2) t o each flask

Make upt o v lume with extraction solution (5.1), mix wel an alow t o s an for (1 ± 5) min Measur

the a sorb nc of the solutions in the same phot ometric c l (6.8) as the samples at 540 nm a ains the

blank o tained in 7.4

Plot the chromium(VI) conc ntrations in mic o rams pe mi l itr (μg ml) a ains the a sorb nc

measur d Plot the chromium(VI) conc ntration on the x-a is and the a sorb nc on the y-a is

In int erla orat ory t es s, the 40 mm c l (6.8) pro ed t o be mos suita le The s an ard solutions

desc ibed a o e ar int en ed for analy sisusing a 40 mm c l In somecases, howeve , it ma besuita le

t o use highe or lowe c l p th length Car shal be taken t o ensur that the calbration rang e used is

within the lnear measuring rang e of the spe tro hot omet er

7.6 Determination of the rec over y rate

7.6.1 Influenc e of the matrix

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 a 1 ml 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 conc ntration b up t o 1 mg kg S le t the conc ntration of the spiking

solution in that wa that the final v lume of the spiked solution is ma imum 1 ml Tr at this solution in

the same wa as the sample (r cording the a sorb nc as A

1s and A

2s ( Se 7.3 )

The a sorb nc of the solution shal be within the rang e of the calbration curve, othe wise r peat he

proc d r using a smale alq ot The r covery rat e shal be gr at er than 8 %

NOTE 1 If the ad ed chromium(VI is not det ect ed, this is an in ication that the le ther contains red cing

ag ents In some cases, if the recovery rat e ac ording t o 7.6.2 is gre t er than 9 %, an aft er int ensive

considerations, this le ds t o the conclusion that his le ther has no chromium(VI cont ent (b low detection limit)

NOTE 2 T e recovery rate is an in icat or of whether the proced re works or whether matrix efects are

afecting the results Normal y, the recovery rat e is gre ter than 8 %

7.6.2 Influenc e of the SPE mater ial (6.9)

Pipett e a v lume of solution (5.5) w hich cor espon s t o the chromium(VI) cont ent of the leathe int o a

1 0 ml v lumetric flask and make up t o volume with extraction solution (5.1)

Tr at this solution in the same wa as the leathe extract Det ermine the cont ent in this solution in

the same wa as that of the leathe extract an comp r with the calculat ed cont ent In cases w he e

no chromium(VI) was det ect ed in the leathe sample, the conc ntration of the solution shal be

6 μg/ 10 ml The r co e y rat e shal be gr at er than 90 % If the r co e y rat e is eq al t o or lowe than

9 %, the SP mat erial isnot suita le for this proc d r an shal be subs itut ed

IULT CS IUC 18-1:2017(E)

8 Calculation and ex pres ion ofresults

8.1 Calculation of chr omium(VI) c ontent

w

Cr V I

( )

=

−

4

(1)

w he e

w

Cr VI)

is the mas fraction, ex r s ed in mi igrams pe kio ram (mg kg), of extracta le

chromi-um(VI)in leathe ;

A

1

is the a sorb nc of sample solution with DPC;

A

2

is the a sorb nc of sample solution without DPC;

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

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

V

0

is the extract v lume of the initial sample, ex r s ed in mi i tr s (ml);

V

1

is the alquot taken from the extract v lume of the initial sample, ex r s ed in mi i tr s (ml);

V

2

is the t otal eluat e (S

1 ) v lume, aft er p s ag e through theSP column, t o w hich the alq ot V

1

wasmade up, ex r s ed in mi i itr s(ml);

V

3

is the alq ot aken from solution S

1 , ex r s ed in mi l ltr s (ml);

V

4

is the f inal make-up v lume of the alq ot from S

1 , ex r s ed in mi i tr s (ml)

R esult b sed on dry matt er:

Cr V I

dr y

Cr V I

-(2)

w he e D is the fact or for conve sion t o dry matt er:

D

w

=

−

1 0

1 0

(3)

w he e w is the mas fraction of the v latie matt er det ermined using ISO 46 4, ex r s ed as a

pe c ntag e

8.2 Rec over y rate (ac c or ding to 7.6.1)

η

ρ

=

−

⋅

⋅

F

1 0

(4 )

w he e

η is the r co e y rat e, ex r s ed in pe c nt ( % );

ρ is t he mas conc nt at ion of chromium(VI) spiked, ex res ed in micro rams pe mi i t re ( μg /ml);

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