Methods Determination of Dobi of Cpo

8/19/2019 Methods Determination of Dobi of Cpo

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MPOB

Test

Mgthod

,,]OS

OF TEST

FOR

PALM OIL

AND

PALiI

OIL

PRODTJCTS:

r'IloN

OF

THE

DETERIORATION

OF

BLEACHAB|LtTy

TNDEX

(DOBI)

OF

CRUDE

PALM

OIL

,re

'--:

a method

for

the determination

'

n

oil.

rrrenced

docum'ents

the deterioration

of bleachability

f

.(\od

contains

provis'ons

\, nich,

through

refe.ence

in this lext,

consril

MPOB

Test

Method.

For dated reference.

s.josequenl

amondmenls

Io

.

I

{hese

publ,calrcns

do not

apply

However.

parl,es

to agreements

based

on Ih

" lrod

are encouraged

to

tnvestigate

the

possjbility

of applying

the most

recs

w

drc Er,lvurdgEu

a nvesogaie

me

possrolrry

or appryrng

tne m

' 'ierenced

documents.

For undaled references,

the lalesl

edition

oflhe

iods p:1

'1:

2004

-

ods

p1.2:

2004

-

Samp

ing oI

palur

oiland

palm

o

tproducls

Prepsraiion

of test sampes

'inition

.

.r

th s [,4POB

Test

[,4eihod.

the

:8i

,. oi bleachabrlity

ndex

(DOBi)

16

nrn

to

thal

at

269

nrn

',rrciple

following

shaliapply

s lhe numericai rari..f

.lr

c measurement

of the

absorbances

at

4:16

nm and

259 nm

.

table

diiution in

iso-octane

(0

5 % to 1%

concentration)

The

.

-i.Ll

in

any other

way

,gents

.

j

I

be o{

recogr,sed

al.a

},r;cal

grad.

2,2,4-trimethylpentan6

(iso,octane)

of

speckoscoptc

or ;quivalent

grade

238

DOB



MPOB

Test

Method

P2.9:

zou+

DOBI

Apparatus

WARNING.

lation.

OuarE

cells,

1O

mm

optlcal

path length'

Volumet.ic

flasks,

25

mL

and

10

mL

capacity

Pipettes

2 nrL

capacily

Sampling

Preparation

of

test

samPle

rrepare

the

sample

in

accodance

lvith

the

melhod

given in

MPOB

Test

Method

p'1'2:

2004

ilijiYff*:i{Hl^f

,l"f#'i:f

H[llE'H":l;il

"s::ff#'rff

:

il'i

*"":ffi

lll

laboratory

apparatus

and,

in

particolar'

the

followinq

Spoctrophotometor,

suitable

for

use

at

269

nm

and

446

nm

Beiore

LJse

il

is

recomme,':red

that

the

wavelength

a^c absorbance

scales

ol the

sp€cirophotometer

Wavclenqth

sctle

mr,

ne

che-'eo

u5

-g

a

f

e''-1

amo

acco'oonce

slr

f

F

i'str-Ten' f

cnu'aciuie's

:'suucl,o's

^r;el,

r

"on,_

grass oo

e.

^-

cr o'o'r'':uo

uo"'oton

o"3's

a'7q

-l

"r

and

28

f

'r

availabte

standard

fliers

which

are

traceab

e 10

rnternallonal

srandards

can

aLso

be

used

s0no,

r,"n,re"-'-ot1")'

.:':---.'1".;;:","'

,..".",-;

.-",.aona(p.,cn-''

00s-o.r

oora.s-r

\oo,,de<o

'rro-

. .'il';";-...."-..",."""0-

0...

r1275 nm

aqa

nst

rhe

0 05

mol/L

potasl

u4r

nYo o)

Take

ca.e

when

handling

potassium

chrom3te

which

is

a

carcinogen

by

Ih imDortant

thar

the

laboralory

recerves

a sample

ihai

is truly

lepresentative

and

has

nol

been

oamaoed

or

changeo

ouring

tlansoort

or

slorage

rethallhesarrp€:slale4anj3lSreoawa/f'omstronglgnt'neolcoo'and'colaredn

,,l,ii'n,i"i oi".J"""""ers'

her-net:cally

sea'eo

wtn

g'ouno

glass or

wa'(ed

co

sloppers

TI,','13;'",ffi:[T":l*",,I""$*"ii,::11:i"f'll:#:o'

*u

r\'4ethod

A

recommended

239



MPOB Tost

Uethod

p2.0:

2004

DOBI

I

Procsdure

3.1

Taat

porilon

.nd

P.oplratlon

otth.

t..t.olutlon

Weigh lo

th6

nearest

0.'1 mg, about 0.1

g

of a completely

molt6d and homog6nis6d

oil

8ampl6

into;25

mL volumetric

fla6k

(6.3).

Dissolvo

and make

up

io

volume with iscoctane

(5

'1).

li

the

solution

is too concentEted,

dilute

it

by pipetting

2

mL inlo

a

10 mL volumetric

flask

(6.3)

and making

up to

volumo with

the solvent

(5.1).

9.2

D6lslminalion

Rin6e

the

quartz

cell

(6.2)

th.ee

times with the

test solution

(9.1).

Fill

the cellwiih

the test

solulion

and measure,

by

means of the spectrophotometer

(6.1),

the absobance

at 446 nm and

269

nm

against

solvent

used

ior d lulion.

F dher dilution

(9.1)

may be necessary

for

samples with

very

high absorbance

values.

10

Expression of

results

Absorbance a1446

nm

DOBI

=

Absorbance at

269

nm

Express

the

resuli io two

dec

nla

places,

11

Precision

Delals

of the

interaboralory

test on the

precision

oflhe

method are

summarised

in AppendixA.

11.1

Repeatability

The absoluie d fference

bet\reen

method

on

ldentica test marena

eq lpn

ent

wlh'n 3 shorl inteNa

overall

repeaiability

imn

(,

0

086

11.2

RoProducibility

tlvo

ndependent single

test results, obtained

uslng the

n the same

Laboratory by the same operator

using

the

same

of lime wrl in not

more lhan 5 % of cases

be

g.eater

than

tha

The absolute

diflerence

beiweei

lwo sing e lesl

results,

obiaLned

usrng ih

s method

on id

lest

maleria

n d iferent

laboratorles with different

operaiors

using dflelent

equipment,

v/ill

more than

5 % of

cases

be

grealer

the

overa

I

reproduclbi

ity limit

(R)

0 039.

12

Test report

The iesl

report shall specify

240



iIPOB'Test

Msthod

P?'9:

the

method

in

accordance

with

which sampling

was carried

out,

if known;

the

method

used;

the

test

re.ult(s);obEinedi

and

if lh€

.eDeatabilitY

has b€en

checked,

the

final

quoted

rsgult

oblained

200I

DOBI

la)

.(b)

,{c)

I

shatl also

mention

all

opela$ng

details

not specifiad

in this

MPOB

Test

M€thod'

or

rcgarded

as

;;;;i

6;ffi;i:h

;iincide-nts

which

mai

have influenced

th€

result(s)'

reporl

shali

incluAe

all

information

necessary

for the

complete

identification

d

the

'ut

Documents

Methods Determination of Dobi of Cpo