DPD Colorimetric Testing for Chlorine Using vacuum ampuls ......Approved and Acceptable Methods NR...

56
DPD Colorimetric Testing for DPD Colorimetric Testing for Chlorine Chlorine Using vacuum ampuls to test for total residual chlorine Micah A Berman

Transcript of DPD Colorimetric Testing for Chlorine Using vacuum ampuls ......Approved and Acceptable Methods NR...

  • DPD

    Col

    orim

    etric

    Tes

    ting

    for

    DPD

    Col

    orim

    etric

    Tes

    ting

    for

    Chl

    orin

    eC

    hlor

    ine U

    sing

    vac

    uum

    am

    puls

    to te

    st fo

    rto

    tal r

    esid

    ual c

    hlor

    ine

    Mic

    ah A

    Ber

    man

  • Ove

    rvie

    wO

    verv

    iew

    DPD

    Col

    orim

    etric

    Tes

    ting

    for C

    hlor

    ine

    Using

    vacu

    um a

    mpu

    ls to

    test

    for t

    otal

    resid

    ual c

    hlorin

    e

    �C

    hem

    istry

    and

    ana

    lytic

    al c

    once

    pts

    �M

    etho

    dolo

    gy�

    Proc

    edur

    e�

    Sum

    mar

    y

  • Che

    mis

    try a

    nd A

    naly

    tical

    Che

    mis

    try a

    nd A

    naly

    tical

    Con

    cept

    sC

    once

    pts

  • Wha

    t is

    DPD

    ?W

    hat i

    s D

    PD?

    �D

    PD is

    N,N

    -die

    thyl

    -p-p

    heny

    lene

    diam

    ine

    –Th

    e a

    min

    e D

    PD re

    agen

    t rea

    cts w

    ith c

    hlor

    ine

    stoi

    chio

    met

    rical

    ly to

    from

    a W

    ürst

    er d

    ye a

    nd a

    nim

    ine.

    –We

    see

    the

    mag

    enta

    Wür

    ster

    dye.

  • Wha

    t’s a

    Vac

    uum

    Am

    pul?

    Wha

    t’s a

    Vac

    uum

    Am

    pul?

    �A

    vac

    uum

    am

    pul i

    s ava

    cuum

    seal

    edsp

    ectro

    phot

    omet

    ric c

    ell.

    �Th

    e am

    pul i

    s sna

    pped

    open

    and

    a fi

    xed

    amou

    ntflu

    id is

    dra

    wn

    into

    the

    ampu

    l.�

    Ther

    e ar

    e of

    ten

    reag

    ents

    inth

    e am

    pul (

    like

    DPD

    ).

    Ben

    efits

    Ben

    efits

    �R

    eage

    nts i

    n va

    cuum

    ampu

    ls a

    re n

    ot p

    rone

    toco

    ntam

    inat

    ion

    due

    anal

    yst

    hand

    ling.

    �Le

    ss tr

    ansf

    errin

    g an

    dm

    easu

    ring

    of s

    olut

    ions

    .So

    lutio

    ns a

    re m

    ade

    and

    read

    in th

    e sa

    me

    ampu

    l.

  • Tech

    nica

    l Con

    side

    ratio

    nsTe

    chni

    cal C

    onsi

    dera

    tions

    �D

    o no

    t wor

    k in

    dire

    ct su

    nlig

    ht.

    –C

    hlor

    ine

    (am

    ong

    othe

    r hal

    ides

    ) is a

    ffec

    ted

    byin

    tens

    e lig

    ht, l

    eadi

    ng to

    err

    ors.

    –If

    wor

    king

    out

    door

    s (on

    -site

    ), be

    sure

    to w

    ork

    in th

    e sh

    ade.

  • Tech

    nica

    l Con

    side

    ratio

    nsTe

    chni

    cal C

    onsi

    dera

    tions

    ��D

    ilute

    pre

    cise

    ly a

    nd a

    ccur

    atel

    y.D

    ilute

    pre

    cise

    ly a

    nd a

    ccur

    atel

    y.–

    Solu

    tions

    less

    than

    0.1

    mg/

    l in

    conc

    entra

    tion

    are

    espe

    cial

    ly v

    ulne

    rabl

    e to

    err

    or.

    –A

    t low

    con

    cent

    ratio

    ns, e

    rror

    s as l

    ittle

    as 0

    .05%

    can

    chan

    ge a

    bsor

    banc

    e m

    easu

    rem

    ents

    by

    over

    15%

    .–

    Dirt

    y gl

    assw

    are

    will

    sign

    ifica

    ntly

    eff

    ect l

    ow-

    conc

    entra

    tion

    solu

    tions

    .

  • Cla

    ss A

    aut

    omat

    ed p

    ipet

    s

  • Tech

    nica

    l Con

    side

    ratio

    nsTe

    chni

    cal C

    onsi

    dera

    tions

    �U

    se g

    ood

    pipe

    t tec

    hniq

    ue.

    –Id

    eally

    , use

    a a

    utom

    ated

    cla

    ss A

    pip

    et.

    –U

    se a

    new

    pip

    et ti

    p fo

    r eac

    h so

    lutio

    n.–

    Nev

    er p

    ipet

    from

    the

    stoc

    k so

    lutio

    n, th

    is c

    anco

    ntam

    inat

    e th

    e w

    hole

    lot.

    Pou

    r the

    solu

    tion

    into

    a sm

    alle

    r bea

    ker f

    irst.

    –If

    usi

    ng a

    pip

    et b

    ulb,

    be

    sure

    not

    to d

    raw

    solu

    tion

    into

    the

    bulb

    itse

    lf.

  • Tech

    nica

    l Con

    side

    ratio

    nsTe

    chni

    cal C

    onsi

    dera

    tions

    �U

    se c

    onsi

    sten

    t tec

    hniq

    ue.

    –D

    ilutio

    ns–

    Tim

    ing

    –R

    eadi

    ngs

    �C

    onsi

    sten

    cy w

    ill m

    inim

    ize

    erro

    rs a

    ndin

    crea

    se th

    e po

    tent

    ial t

    o id

    entif

    y an

    dco

    rrec

    t err

    ors.

  • Met

    hodo

    logy

    Met

    hodo

    logy

  • Appr

    oved

    and

    Acc

    epta

    ble

    Met

    hods

    Appr

    oved

    and

    Acc

    epta

    ble

    Met

    hods

    NR

    219

    EPA

    330.

    5 or

    Std.

    Mth

    ds.

    4500

    -Cl G

    �N

    R 2

    19 li

    sts S

    tand

    ard

    Met

    hods

    450

    0-C

    lG

    and

    EPA

    met

    hod

    330.

    5 as

    the

    ON

    LYac

    cept

    able

    met

    hods

    for D

    PD te

    stin

    g of

    tota

    l res

    idua

    l chl

    orin

    e.�

    NR

    809

    list

    s Std

    . Met

    hods

    450

    0-C

    l G o

    ran

    y EP

    A a

    ppro

    ved

    met

    hod.

    Thu

    s any

    appr

    oved

    met

    hod

    can

    be u

    sed

    unde

    r NR

    809.

    NR

    809

    Std.

    Mth

    ds.

    4500

    -Cl G

    or

    EPA

    appr

    oved

    met

    hods

    �Th

    ese

    met

    hods

    are

    ver

    yte

    chni

    cally

    dem

    andi

    ngan

    d tim

    e co

    nsum

    ing.

    Ther

    e ar

    e m

    any

    com

    mer

    cial

    met

    hods

    avai

    labl

    e th

    at si

    mpl

    ifyth

    e pr

    oced

    ure.

  • Appr

    oved

    and

    Acc

    epte

    d M

    etho

    dsAp

    prov

    ed a

    nd A

    ccep

    ted

    Met

    hods

    If y

    ou a

    re g

    oing

    to u

    se a

    com

    mer

    cial

    test

    , the

    ir m

    ust b

    e do

    cum

    enta

    tion

    that

    the

    test

    met

    hod

    is a

    ppro

    ved.

    NR

    219

    EPA

    330.

    5 OR

    Std.

    Mth

    ds.

    4500

    -Cl G

    If a

    com

    mer

    cial

    met

    hod

    is a

    ccep

    ted

    by th

    eU

    SEPA

    as e

    quiv

    alen

    t to

    one

    (usu

    ally

    bot

    h) o

    f the

    met

    hods

    list

    ed in

    NR

    219,

    than

    it c

    an b

    e us

    ed fo

    rre

    porti

    ng p

    urpo

    ses t

    o th

    e W

    DN

    R f

    or N

    R 2

    19 (i

    nad

    ditio

    n to

    NR

    809

    ).

    Let

    ter

    from

    USE

    PAin

    dica

    ting

    acce

    ptan

    ceof

    com

    mer

    cial

    test

    met

    hod

    Commercial Test

  • Appr

    oved

    and

    Acc

    epte

    d M

    etho

    dsAp

    prov

    ed a

    nd A

    ccep

    ted

    Met

    hods

    �H

    ach

    Met

    hod

    8021

    �H

    ach

    Met

    hod

    8167

    �H

    ach

    Met

    hod

    8370

    The

    follo

    win

    g is

    a li

    st o

    f som

    e co

    mm

    erci

    al D

    PDm

    etho

    ds th

    at a

    re U

    SEPA

    acc

    epte

    d. T

    his l

    ist i

    sby

    nei

    ther

    exc

    lusi

    ve n

    or c

    ompl

    ete.

    �H

    ach

    Met

    hod

    8371

    �H

    ach

    Met

    hod

    1001

    4

    NO

    TE:

    Alth

    ough

    all

    of th

    ese

    met

    hods

    use

    DPD

    , the

    ydo

    not

    nec

    essa

    rily

    use

    vacu

    um a

    mpu

    ls.

    Whe

    n us

    ing

    a co

    mm

    erci

    al te

    st, i

    t is

    nece

    ssar

    y to

    cite

    the

    SPEC

    IFIC

    met

    hod

    (e.g

    .m

    etho

    d nu

    mbe

    r) y

    ou a

    re u

    sing

    . A

    test

    cate

    gory

    is n

    ot a

    ccep

    tabl

    e.

  • Appr

    oved

    and

    Acc

    epta

    ble

    Appr

    oved

    and

    Acc

    epta

    ble

    Met

    hods

    - A

    Not

    e of

    Cau

    tion

    Met

    hods

    - A

    Not

    e of

    Cau

    tion

    �Th

    e co

    mm

    erci

    al m

    etho

    ds o

    ften

    glos

    s ove

    r the

    ver

    yim

    porta

    nt a

    spec

    ts o

    f tra

    ceab

    ility

    , cal

    ibra

    tion,

    spik

    es,

    dupl

    icat

    es, a

    nd o

    ther

    QA

    and

    QC

    mea

    sure

    s.�

    Usi

    ng a

    com

    mer

    cial

    met

    hod

    does

    not

    exe

    mpt

    you

    from

    the

    QA

    and

    QC

    est

    ablis

    hed

    in th

    e or

    igin

    al E

    PA/S

    td.

    Met

    hods

    : C

    omm

    erci

    al M

    etho

    d +

    QA/

    QC

    = A

    ccep

    tabl

    e Te

    stin

    g

  • Com

    mer

    cial

    Met

    hods

    -C

    omm

    erci

    al M

    etho

    ds -

    Thor

    ough

    ness

    Thor

    ough

    ness

    �Th

    e ex

    clus

    ive

    use

    ofge

    neric

    inst

    ruct

    ions

    are

    not a

    ccep

    tabl

    e.–

    No

    true

    calib

    ratio

    n–

    No

    QC

    –N

    o sp

    ikes

    /dup

    es�

    Thes

    e in

    stru

    ctio

    nsar

    e us

    eful

    for q

    uick

    chec

    ks a

    nd su

    mm

    ary

    only

    Gen

    eric

    Inst

    ruct

    ion

    Thes

    e in

    stru

    ctio

    ns a

    re s

    impl

    istic

    . Al

    one,

    they

    are

    insu

    ffici

    ent f

    or p

    rope

    r tes

    ting.

  • Qui

    ck T

    ests

    for C

    hlor

    ine

    Test

    ing

    Qui

    ck T

    ests

    for C

    hlor

    ine

    Test

    ing

    �C

    olor

    whe

    els a

    reN

    OT

    acce

    ptab

    le.

    �“P

    ocke

    t col

    orim

    eter

    s”ar

    e N

    OT

    acce

    ptab

    le.

    –Th

    ese

    colo

    rimet

    ers

    use

    an in

    suff

    icie

    nt,

    prep

    rogr

    amm

    edca

    libra

    tion.

    �M

    ust u

    se tr

    uesp

    ectro

    phot

    omet

    ers

    or c

    olor

    imet

    ers w

    itha

    USE

    PA-a

    ccep

    ted

    met

    hod.

    Thes

    e ar

    e N

    OT

    USE

    PA a

    ccep

    ted

  • Proc

    edur

    ePr

    oced

    ure

  • Prep

    arin

    g Po

    tass

    ium

    Prep

    arin

    g Po

    tass

    ium

    Perm

    anga

    nate

    Sta

    ndar

    dPe

    rman

    gana

    te S

    tand

    ard

    �In

    this

    test

    a p

    otas

    sim

    per

    man

    gana

    test

    anda

    rd is

    use

    d instead

    of a

    chl

    orin

    est

    anda

    rd.

    Pota

    ssiu

    m p

    erm

    anga

    nate

    is m

    ore

    stab

    le th

    an c

    hlor

    ine,

    and

    is u

    sed

    as a

    mor

    ere

    liabl

    e su

    bstit

    ute

    stan

    dard

    .

  • Prep

    arin

    g Po

    tass

    ium

    Prep

    arin

    g Po

    tass

    ium

    Perm

    anga

    nate

    Sta

    ndar

    dPe

    rman

    gana

    te S

    tand

    ard

    �O

    btai

    n ve

    ndor

    pre

    pare

    d po

    tass

    ium

    perm

    anga

    nate

    stan

    dard

    solu

    tion

    for u

    se in

    DPD

    or F

    AS

    colo

    rimet

    ric m

    etho

    ds.

    –St

    anda

    rd so

    lutio

    n sh

    ould

    be

    labe

    led

    0.89

    1g/l

    pota

    ssiu

    m p

    erm

    anga

    ntat

    e. T

    his i

    s equ

    ival

    ent

    to 1

    g/l (

    1000

    ppm

    ) tot

    al r

    esid

    ual c

    hlor

    ine.

    –Th

    e st

    anda

    rd so

    lutio

    n sh

    ould

    com

    e in

    a d

    ark

    ambe

    r gla

    ss b

    ottle

    . Th

    is b

    ottle

    shou

    ld b

    est

    ored

    in th

    e da

    rk, a

    way

    from

    dire

    ct su

    nlig

    ht.

  • Dar

    k bo

    ttle

    prev

    ents

    degr

    adat

    ion

    due

    to li

    ght

    Stan

    dard

    is o

    f cor

    rect

    conc

    entra

    tion

    and

    labe

    led

    appr

    opria

    tely

    Prep

    arin

    g Po

    tass

    ium

    Prep

    arin

    g Po

    tass

    ium

    Perm

    anga

    nate

    Sta

    ndar

    dPe

    rman

    gana

    te S

    tand

    ard

  • Prep

    arin

    g Po

    tass

    ium

    Prep

    arin

    g Po

    tass

    ium

    Perm

    anga

    nate

    Sta

    ndar

    dPe

    rman

    gana

    te S

    tand

    ard

    �D

    ilute

    the

    1000

    ppm

    stoc

    k so

    lutio

    nto

    1 p

    pm w

    orki

    ng so

    lutio

    n (1

    :100

    0)as

    follo

    ws:

    1) D

    ilute

    10.

    00 m

    l sto

    ck so

    lutio

    n to

    100.

    0 m

    l (w

    ith d

    istil

    led

    wat

    er in

    avo

    lum

    etric

    flas

    k)2)

    Tak

    e 1.

    00 m

    l of t

    his n

    ewso

    lutio

    n an

    d di

    lute

    it to

    100.

    0 m

    l.–

    Be

    sure

    to m

    ix e

    ach

    dilu

    tion

    thor

    ough

    ly.

    Stoc

    kso

    l.(1

    000p

    pm)

    Wor

    king

    sol.

    (1 p

    pm)

    Rem

    embe

    r:Th

    e co

    ncen

    trat

    ions

    are

    equi

    vale

    nts.

    The

    yso

    lutio

    ns a

    re n

    otA

    CTU

    ALL

    Y ch

    lorin

    e,bu

    t beh

    ave

    like

    chlo

    rine

    at th

    eeq

    uiva

    lent

    conc

    entr

    atio

    n.

  • Prep

    arin

    g C

    alib

    ratio

    n St

    anda

    rds

    Prep

    arin

    g C

    alib

    ratio

    n St

    anda

    rds

    �Fr

    esh

    wor

    king

    solu

    tion

    for u

    se in

    calib

    ratio

    n st

    anda

    rds m

    ust b

    e pr

    epar

    edfr

    esh

    for t

    hat d

    ay.

    �R

    ange

    of c

    alib

    ratio

    n st

    anda

    rds m

    ust

    incl

    ude

    the

    antic

    ipat

    ed sa

    mpl

    e ra

    nge.

    –If

    you

    exp

    ect s

    ampl

    es b

    etw

    een

    0.03

    0 –

    0.15

    0pp

    m (t

    ypic

    al fo

    r was

    tew

    ater

    and

    drin

    king

    wat

    er a

    naly

    sis)

    , the

    n ca

    libra

    te fr

    om 0

    .020

    –0.

    200

    ppm

    .�

    Do

    not p

    repa

    re c

    alib

    ratio

    n st

    anda

    rds b

    elow

    0.02

    0 pp

    m.

    Thes

    e w

    ill le

    ad to

    err

    or.

    �Se

    t up

    a ta

    ble

    to h

    elp

    calc

    ulat

    e di

    lutio

    ns

  • Prep

    arin

    g C

    alib

    ratio

    n St

    anda

    rds

    Prep

    arin

    g C

    alib

    ratio

    n St

    anda

    rds

    0.20

    ppm

    100

    ml

    20.0

    0 m

    l

    0.10

    ppm

    100

    ml

    10.0

    0 m

    l

    0.07

    ppm

    100

    ml

    7.00

    ml

    0.05

    ppm

    100

    ml

    5.00

    ml

    0.03

    ppm

    100

    ml

    3.00

    ml

    Fina

    l Con

    cent

    ratio

    nFi

    nal V

    olum

    eW

    orki

    ng S

    olut

    ion

    1ppm�

    Exam

    ple

    dilu

    tion

    tabl

    e.D

    ilute

    wor

    king

    solu

    tion

    (1pp

    m) w

    ith D

    I wat

    er u

    p to

    the

    final

    vol

    ume

    in a

    100

    ml v

    olum

    etric

    flas

    k:

  • Prep

    arin

    g C

    alib

    ratio

    n St

    anda

    rds

    Prep

    arin

    g C

    alib

    ratio

    n St

    anda

    rds

    �C

    alib

    ratio

    n st

    anda

    rds a

    re la

    bele

    d, fi

    lled

    to m

    enis

    cus,

    and

    thor

    ough

    ly m

    ixed

    .

    �C

    alib

    ratio

    n bl

    ank

    (DI w

    ater

    ) is i

    nclu

    ded,

    and

    pre

    pare

    d lik

    e al

    l oth

    er st

    anda

    rds.

    Not

    e: th

    is p

    hoto

    grap

    h re

    flect

    sco

    ncen

    trat

    ions

    in p

    pb, n

    ot p

    pm

  • Dev

    elop

    ing

    Cal

    ibra

    tion

    Stan

    dard

    sD

    evel

    opin

    g C

    alib

    ratio

    n St

    anda

    rds

    �Po

    ur a

    smal

    l am

    ount

    of

    calib

    ratio

    n st

    anda

    rd fr

    omth

    e vo

    lum

    etric

    flas

    k in

    toa

    smal

    l bea

    ker a

    nd p

    lace

    the

    beak

    er in

    fron

    t of t

    hefla

    sk.

    �D

    o th

    is fo

    r eac

    hca

    libra

    tion

    stan

    dard

    ,in

    clud

    ing

    the

    calib

    ratio

    nbl

    ank

    (DI w

    ater

    ).

    �B

    egin

    a ti

    mer

    – b

    reak

    one

    ampu

    l ups

    ide

    dow

    n in

    the

    beak

    ers.

    –B

    e su

    re th

    at re

    agen

    tis

    not

    in a

    mpu

    l tip

    .–

    Bre

    ak ti

    p ag

    ains

    tbo

    ttom

    or w

    all o

    fbe

    aker

    .–

    Allo

    w a

    mpu

    l to

    fill

    com

    plet

    ely

    (1-2

    s).

  • How

    to B

    reak

    an

    Ampu

    lH

    ow to

    Bre

    ak a

    n Am

    pul

    •Rea

    gent

    is in

    tip

    of a

    mpu

    l.•R

    eage

    nt is

    like

    ly st

    ay in

    side

    the

    brok

    en ti

    p af

    ter i

    t bre

    aks,

    incr

    easi

    ng c

    hanc

    e fo

    r low

    bias

    .

    •Am

    pul i

    s han

    dled

    care

    fully

    to a

    void

    reag

    ent f

    allin

    g in

    to tip.

  • How

    to B

    reak

    an

    Ampu

    lH

    ow to

    Bre

    ak a

    n Am

    pul

    •Bea

    ker a

    ndam

    pul a

    retip

    ped

    to th

    esi

    de.

    •Rea

    gent

    ism

    ore

    likel

    y to

    stay

    in th

    eam

    pul a

    nd n

    otfa

    ll in

    to ti

    p.

    •Am

    pul i

    s too

    ver

    tical

    .•R

    eage

    nt is

    like

    ly to

    fall

    into

    tip

    befo

    re it

    brea

    ks.

  • DPD

    Col

    or L

    evel

    sD

    PD C

    olor

    Lev

    els

    “Typ

    ical

    ”ch

    lorin

    e sa

    mpl

    e- l

    ight

    mag

    enta

    “Str

    ong”

    chlo

    rine

    sam

    ple

    - dee

    p m

    agen

    ta

    “Ove

    rsho

    t”ch

    lorin

    e sa

    mpl

    e- r

    eddi

    sh b

    row

    n

    Des

    troy

    ed D

    PD- c

    olor

    less

    (pur

    e ch

    lorin

    ebl

    each

    )

  • Mak

    ing

    a C

    alib

    ratio

    n C

    urve

    Mak

    ing

    a C

    alib

    ratio

    n C

    urve

    Zero

    ing

    the

    Spec

    troph

    otom

    eter

    Zero

    ing

    the

    Spec

    troph

    otom

    eter

    �Ze

    ro th

    e sp

    ectro

    phot

    omet

    er u

    sing

    the

    calib

    ratio

    n bl

    ank,

    DI w

    ater

    –M

    ake

    sure

    the

    spec

    troph

    otom

    eter

    is se

    t to

    515

    nm.

    If th

    is is

    not

    pos

    sibl

    e, u

    se a

    wav

    elen

    gth

    betw

    een

    515

    -540

    nm

    .–

    Zero

    with

    the

    sam

    e w

    ater

    that

    was

    use

    d in

    crea

    ting

    the

    calib

    ratio

    n st

    anda

    rds.

    –Po

    ur th

    e w

    ater

    from

    the

    flask

    into

    a c

    lean

    sam

    ple

    cell.

    Wip

    e th

    e ce

    ll cl

    ean

    offin

    gerp

    rints

    .–

    Alig

    n th

    e re

    fere

    nce

    mar

    k to

    the

    light

    sour

    ce (o

    r as a

    ppro

    pria

    te),

    and

    zero

    the

    spec

    troph

    otom

    eter

    .

    Fing

    erpr

    ints

    , du

    st,

    and

    othe

    r re

    sidu

    es c

    an b

    ias

    abso

    rban

    ce r

    eadi

    ngs.

    Be

    sure

    to

    clea

    nly

    wip

    e of

    fth

    e op

    tical

    su

    rfac

    e of

    any

    sam

    ple

    cell

    or a

    mpu

    lth

    at is

    ana

    lyze

    d w

    ith t

    hesp

    ectr

    opho

    tom

    eter

    .

  • Wav

    elen

    gth

    set c

    orre

    ctly

    DI

    Cal

    ibra

    tion

    blan

    k is

    insa

    mpl

    e ce

    ll an

    dal

    igne

    d pr

    oper

    ly

    Lig

    htsh

    ield

    rem

    oved

    Mak

    ing

    a C

    alib

    ratio

    n C

    urve

    Mak

    ing

    a C

    alib

    ratio

    n C

    urve

    Zero

    ing

    the

    Spec

    trom

    eter

    Zero

    ing

    the

    Spec

    trom

    eter

    Ligh

    tsh

    ield

    inpl

    ace

    Dev

    ice

    isze

    roed

  • Mak

    ing

    a C

    alib

    ratio

    n C

    urve

    :M

    akin

    g a

    Cal

    ibra

    tion

    Cur

    ve:

    Rec

    ord

    Dat

    aR

    ecor

    d D

    ata

    �R

    ecor

    d th

    eab

    sorb

    ance

    of e

    ach

    calib

    ratio

    n st

    anda

    rd�

    This

    dat

    a is

    use

    dw

    hen

    calc

    ulat

    ing

    aca

    libra

    tion

    curv

    e.

  • Mak

    ing

    a C

    alib

    ratio

    n C

    urve

    :M

    akin

    g a

    Cal

    ibra

    tion

    Cur

    ve:

    Det

    erm

    inin

    g r

    Det

    erm

    inin

    g r (

    corre

    latio

    n co

    effic

    ient

    )(c

    orre

    latio

    n co

    effic

    ient

    )

    �U

    se a

    cal

    cula

    tor,

    Exce

    l, or

    oth

    er so

    ftwar

    e.�

    In E

    xcel

    , you

    can

    use

    the

    CO

    RR

    EL fo

    rmul

    a.�

    CO

    RR

    EL(V

    alue

    s 1,V

    alue

    s 2) r

    etur

    ns th

    e co

    rrel

    atio

    n co

    effic

    ient

    , r.

    �M

    any

    scie

    ntifi

    c ca

    lcul

    ator

    s can

    cal

    cula

    te r

    as w

    ell.

    00.

    000

    300.

    016

    500.

    029

    100

    0.05

    615

    00.

    080

    200

    0.10

    025

    00.

    135

    r =0.

    9980

    79

    =CO

    RREL

    (A1:

    A7,B

    1:B7

    )

  • �r d

    escr

    ibes

    how

    muc

    h of

    a c

    orre

    latio

    n th

    ere

    isbe

    twee

    n th

    e tw

    o da

    ta se

    ts.

    Clic

    k he

    re fo

    r mor

    e in

    form

    atio

    n .�

    In th

    is c

    ase,

    it d

    escr

    ibes

    how

    linear

    the

    data

    is.

    �W

    hy sh

    ould

    the

    data

    be

    linea

    r?�

    Bec

    ause

    of B

    eer’

    s law

    .

    Mak

    ing

    a C

    alib

    ratio

    n C

    urve

    :M

    akin

    g a

    Cal

    ibra

    tion

    Cur

    ve:

    Abou

    t rAb

    out r

  • Mak

    ing

    a C

    alib

    ratio

    n C

    urve

    :M

    akin

    g a

    Cal

    ibra

    tion

    Cur

    ve:

    Beer

    ’s L

    awBe

    er’s

    Law

    �B

    eer’

    s law

    stat

    es th

    atA

    = ε

    bcε

    =m

    olar

    abs

    orpt

    ivity

    (how

    “po

    tent

    ” th

    e dy

    e is

    )b

    =ce

    ll pa

    th le

    ngth

    c =

    conc

    entra

    tion

    �Si

    nce

    the

    mol

    ar a

    bsor

    ptiv

    ity a

    nd th

    e pa

    th le

    ngth

    are

    the

    sam

    e fo

    r all

    read

    ings

    , onl

    y th

    e th

    e co

    ncen

    tratio

    nch

    ange

    s. T

    hus,

    if th

    e co

    ncen

    tratio

    n do

    uble

    s, so

    shou

    ld th

    e ab

    sorb

    ance

    (A).

    Thi

    s is a

    linear

    rela

    tions

    hip.

    �If

    cal

    ibra

    tion

    data

    is n

    ot li

    near

    (r <

    .995

    ), th

    an th

    ere

    is a

    pro

    blem

    in e

    ither

    the

    proc

    edur

    e or

    cal

    ibra

    tion

    stsa

    ndar

    d.

  • Mak

    ing

    a C

    alib

    ratio

    n C

    urve

    :M

    akin

    g a

    Cal

    ibra

    tion

    Cur

    ve:

    Line

    ar R

    egre

    ssio

    nLi

    near

    Reg

    ress

    ion

    �O

    nce

    you

    know

    that

    the

    data

    is v

    alid

    (r >

    .995

    ),yo

    u w

    ill n

    eed

    to c

    alcu

    late

    the

    linea

    r reg

    ress

    ion,

    or th

    e “l

    ine

    of b

    est f

    it”.

    �Th

    is c

    an b

    e do

    neon

    a c

    alcu

    lato

    r or

    othe

    r sof

    twar

    e.0

    0.00

    00.

    030

    0.01

    60.

    050

    0.02

    90.

    100

    0.05

    60.

    150

    0.08

    00.

    200

    0.10

    00.

    250

    0.13

    5r

    =0.

    9980

    79=

    CO

    RR

    EL

    (A1:

    A7,

    B1:

    B

    Cal

    ibra

    tion

    Cur

    ve (p

    erm

    anga

    nate

    chl

    orin

    e eq

    uiva

    lent

    )

    y =

    0.52

    2974

    x +

    0.00

    1154

    0.00

    0

    0.02

    0

    0.04

    0

    0.06

    0

    0.08

    0

    0.10

    0

    0.12

    0

    0.14

    0

    0.16

    0 0.00

    00.

    100

    0.20

    00.

    300

    Con

    c. (p

    pm)

    Absorbance

  • Mak

    ing

    a C

    alib

    ratio

    n C

    urve

    :M

    akin

    g a

    Cal

    ibra

    tion

    Cur

    ve:

    Che

    ck C

    alib

    ratio

    nC

    heck

    Cal

    ibra

    tion

    �C

    alib

    ratio

    n is

    val

    id w

    hen

    r > .9

    95 a

    nd th

    ey-

    inte

    rcep

    t (th

    e “b

    ” in

    y=m

    x+b)

    is b

    elow

    the

    limit

    of d

    etec

    tion

    (LO

    D).

    �Th

    ere

    is e

    xten

    sive

    cal

    ibra

    tion

    info

    rmat

    ion

    on a

    vaila

    ble

    in o

    ther

    DN

    R p

    rese

    ntat

    ions

    .C

    heck

    it o

    ut!

  • Anal

    yzin

    g a

    Sam

    ple

    Anal

    yzin

    g a

    Sam

    ple

    –Ze

    ro th

    e sp

    ectro

    met

    er w

    ith D

    Iw

    ater

    –R

    ecor

    d ab

    sorb

    ance

    of b

    lank

    (pur

    esa

    mpl

    e)

    –R

    ecor

    d ab

    sorb

    ance

    of d

    evel

    oped

    sam

    ple

    (sam

    ple

    + D

    PD in

    am

    pul).

    �Th

    ere

    are

    thre

    e st

    eps t

    o an

    alyz

    ing

    a sa

    mpl

    e.

    Dev

    elop

    ed sa

    mpl

    e

  • �D

    evel

    oped

    (sol

    utio

    n +

    DPD

    ) sam

    ples

    or s

    tand

    ards

    shou

    ld n

    ot b

    e re

    ad b

    efor

    e th

    ree

    min

    utes

    , or a

    fter s

    ixm

    inut

    es.

    Rea

    d th

    em b

    etw

    een

    3-6

    min

    utes

    .�

    Set u

    p a

    timin

    g sc

    hedu

    le to

    max

    imiz

    e ef

    ficie

    ncy.

    �En

    sure

    that

    eac

    h sa

    mpl

    e de

    velo

    ps fo

    r a c

    onsi

    sten

    tam

    ount

    of t

    ime

    befo

    re it

    is re

    ad.

    Develop Sample # 1 �

    Develop Sample # 2 �

    Develop Sample # 3 �

    Develop Sample # 4 �

    Develop Sample # 5 �

    Develop Sample # 6 �

    Read Sample # 1�

    Read Sample # 3�

    Read Sample # 2�

    Read Sample # 4�An

    alyz

    ing

    a Sa

    mpl

    e - T

    imin

    gAn

    alyz

    ing

    a Sa

    mpl

    e - T

    imin

    g

    etc.

    .

    Exam

    ple

    timin

    g sc

    hedu

    le fo

    r thr

    ee m

    inut

    e de

    velo

    ping

    tim

    e fo

    r six

    sam

    ples

    .

  • Anal

    yzin

    g a

    Sam

    ple

    Anal

    yzin

    g a

    Sam

    ple

    �W

    hen

    anal

    yzin

    g a

    sam

    ple

    reco

    rd b

    oth

    abso

    rban

    ces

    (bla

    nk a

    nd d

    evel

    oped

    ) on

    the

    data

    shee

    t.�

    Subt

    ract

    the

    blan

    k ab

    sorb

    ance

    from

    the

    deve

    lope

    dab

    sorb

    ance

    to g

    et th

    e ad

    just

    ed a

    bsor

    banc

    e.�

    This

    adj

    uste

    d ab

    sorb

    ance

    cor

    rect

    s for

    any

    nat

    ural

    abso

    rban

    ce o

    f the

    sam

    ple

    or a

    mpu

    l its

    elf.

    Sam

    ple

    no.

    Blan

    kD

    evel

    oped

    Adj.

    Abs.

    Out

    fall

    no. 1

    0.00

    30.

    032

    0.02

    9O

    utfa

    ll no

    . 20.

    003

    0.04

    80.

    045

    Out

    fall

    no. 3

    0.00

    00.

    046

    0.04

    6O

    utfa

    ll no

    . 40.

    002

    0.03

    50.

    033

    DEV

    ELO

    PED

    - B

    LAN

    K =

    Adj

    uste

    d A

    bsor

    banc

    e

  • Cal

    ibra

    tion

    Cur

    ve (p

    erm

    anga

    nate

    chl

    orin

    e eq

    uiva

    lent

    )

    y =

    0.52

    2974

    x +

    0.00

    1154

    0.00

    0

    0.02

    0

    0.04

    0

    0.06

    0

    0.08

    0

    0.10

    0

    0.12

    0

    0.14

    0

    0.16

    0 0.00

    00.

    100

    0.20

    00.

    300

    Con

    c. (p

    pm)

    Absorbance

    Anal

    yzin

    g a

    Sam

    ple

    Anal

    yzin

    g a

    Sam

    ple

    �Th

    e ad

    just

    edab

    sorb

    ance

    s are

    the

    only

    val

    ues t

    hat a

    reus

    ed in

    cal

    cula

    tions

    .

    [.065

    ] =

    .522

    974(

    x) +

    .011

    54

    x=.1

    02 p

    pm[C

    orre

    cted

    Abs

    .]=

    .5

    2297

    4(co

    nc. o

    f sam

    ple)

    +.0

    1154

    �Le

    t say

    , for

    inst

    ance

    , tha

    t a sa

    mpl

    e ha

    s a c

    orre

    cted

    abs

    orba

    nce

    of .0

    65.

    Use

    bac

    k-ca

    lcul

    atio

    n to

    cal

    cula

    te th

    e co

    ncen

    tratio

    n of

    sam

    ple,

    usi

    ng th

    elin

    ear r

    egre

    ssio

    n eq

    uatio

    n. S

    olve

    for (

    x).

    �Th

    ese

    valu

    es a

    re“p

    lugg

    ed”

    into

    the

    linea

    r reg

    ress

    ion

    equa

    tion

    to g

    et a

    conc

    entra

    tion.

  • Sum

    mar

    ySu

    mm

    ary

    �M

    ake

    sure

    to u

    se a

    n U

    SEPA

    acc

    epte

    dm

    etho

    d, a

    nd b

    e ab

    le to

    cite

    whi

    ch m

    etho

    dth

    at is

    .�

    Be

    sure

    to c

    alib

    rate

    car

    eful

    ly.

    Che

    ck th

    atca

    libra

    tion

    is v

    alid

    (>.9

    95).

    �D

    eter

    min

    e lin

    e of

    bes

    t fit.

    �U

    se e

    quat

    ion

    from

    line

    of b

    est f

    it to

    bac

    k-ca

    lcul

    ate

    abso

    rban

    ces f

    rom

    sam

    ples

    .

  • Addi

    tiona

    l Inf

    orm

    atio

    nAd

    ditio

    nal I

    nfor

    mat

    ion

  • Abou

    t Low

    Lev

    el T

    estin

    gAb

    out L

    ow L

    evel

    Tes

    ting

    �Lo

    w le

    vel t

    estin

    g is

    esp

    ecia

    lly p

    rone

    to th

    eef

    fect

    s of i

    nter

    nal r

    efle

    ctio

    ns.

    �In

    tern

    al re

    flect

    ions

    :–

    light

    -sca

    tterin

    g/re

    flect

    ing

    affe

    cts a

    ssoc

    iate

    d w

    ith th

    esa

    mpl

    e ce

    ll/am

    pul i

    tsel

    f (no

    t its

    con

    tent

    s).

    Ligh

    tso

    urce

    Det

    ecto

    rSa

    mpl

    ece

    ll(b

    lank

    )

    Nor

    mal

    lytr

    avel

    ing

    light

    Lig

    htaf

    fect

    ed b

    yin

    tern

    alre

    flect

    ions

    (<.0

    1%)

    �Th

    ese

    effe

    cts

    are

    usua

    llyin

    sign

    ifica

    nt.

  • Typi

    cal

    Typi

    cal S

    pect

    roph

    otom

    etry

    Spec

    troph

    otom

    etry

    Typi

    cal B

    lank

    —Li

    ttle

    abso

    rban

    ce

    —M

    ost o

    f the

    ligh

    t goe

    sth

    roug

    h

    Typi

    cal (

    deve

    lope

    d) S

    ampl

    e

    —Si

    gnifi

    cant

    Abs

    orba

    nce

    —A

    sign

    ifica

    nt a

    mou

    nt o

    flig

    ht is

    abs

    orbe

    dStrong signal

    Weaker Signal

    �A

    bsor

    banc

    e

    =

    Stro

    ng

    -W

    eak = st

    rong

    �U

    ncer

    tain

    ty d

    ue to

    diff

    eren

    t int

    erna

    l ref

    lect

    ions

    is in

    sign

    ifica

    nt

    �Id

    eally

    , the

    re is

    a si

    gnifi

    cant

    diff

    eren

    ce b

    etw

    een

    the

    blan

    k an

    dsa

    mpl

    e. T

    he ra

    ndom

    diff

    eren

    ces i

    n sc

    atte

    ring

    effe

    cts o

    f diff

    eren

    tce

    lls is

    insi

    gnifi

    cant

    .

  • Low

    -Lev

    el

    Low

    -Lev

    el S

    pect

    roph

    otom

    etry

    Spec

    troph

    otom

    etry

    Bla

    nk

    —Li

    ttle

    abso

    rban

    ce

    —M

    ost o

    f the

    ligh

    t goe

    sth

    roug

    h

    Low

    abs

    orba

    nce

    sam

    ple

    —Li

    ttle

    abso

    rban

    ce

    —M

    ost o

    f the

    ligh

    t goe

    sth

    roug

    hStrong signal

    Strong Signal

    �A

    bsor

    banc

    e

    =

    Stro

    ng

    -

    Stro

    ng =

    ~~ 00

    �U

    ncer

    tain

    ty d

    ue to

    diff

    eren

    t int

    erna

    l ref

    lect

    ions

    is m

    ore

    sign

    ifica

    nt

    �Th

    e bl

    ank

    and

    the

    sam

    ple

    are

    near

    ly id

    entic

    al�

    Diff

    ernc

    es b

    etw

    een

    cells

    bec

    ome

    sign

    ifica

    nt.

  • Low

    -Lev

    el

    Low

    -Lev

    el S

    pect

    roph

    otom

    etry

    Spec

    troph

    otom

    etry

    ::M

    inim

    izin

    g In

    tern

    al R

    efle

    ctio

    nsM

    inim

    izin

    g In

    tern

    al R

    efle

    ctio

    ns�

    Use

    reag

    ent-f

    ree

    ampu

    ls fo

    r bla

    nk a

    nd/o

    r zer

    o–

    Bla

    nk a

    mpu

    ls a

    re id

    entic

    al to

    DPD

    am

    puls

    , but

    cont

    ain

    no D

    PD re

    agen

    t–

    Min

    imiz

    es th

    e di

    ffer

    ence

    s in

    inte

    rnal

    refle

    ctio

    nsbe

    twee

    n re

    adin

    gs–

    This

    is so

    mew

    hat m

    ore

    cost

    ly (~

    50

    cent

    s per

    bla

    nkam

    pul)

    but w

    ill im

    prov

    e re

    sults

    .

  • Low

    -Lev

    el

    Low

    -Lev

    el S

    pect

    roph

    otom

    etry

    Spec

    troph

    otom

    etry

    ::M

    inim

    izin

    g In

    tern

    al R

    efle

    ctio

    nsM

    inim

    izin

    g In

    tern

    al R

    efle

    ctio

    ns�

    Use

    cel

    ls th

    at w

    / 25m

    m+

    path

    leng

    th–

    Cel

    ls sm

    alle

    r tha

    n 25

    mm

    acr

    oss w

    illyi

    eld

    low

    abs

    orba

    nces

    . In

    tern

    alre

    flect

    ions

    will

    be

    mor

    e si

    gnifi

    cant

    .�

    Avo

    id d

    ilutin

    g sa

    mpl

    e–

    Dilu

    ting

    the

    sam

    ple

    will

    furth

    erde

    crea

    se it

    s abs

    orba

    nce.

    �U

    se fl

    ow-th

    roug

    h ce

    ll to

    eliminate

    erro

    rs d

    ue to

    inte

    rnal

    refle

    ctio

    n.–

    Cos

    tly, b

    ut si

    gnifi

    cant

    ly im

    prov

    esre

    sults

    .

    Sam

    ple

    Cel

    l

    > 25

    mm

  • Abou

    t rAb

    out r

    �Le

    t’s lo

    ok a

    t the

    men

    of H

    appy

    ville

    . D

    ata

    was

    col

    lect

    edco

    ncer

    ning

    hei

    ght a

    nd w

    eigh

    t. It

    is sh

    own

    belo

    w.

    Heigh

    tAve

    rage

    W

    eight

    5' 2"

    142.

    15''

    4"

    147.

    75'

    6"15

    6.0

    5' 8"

    164.

    35'

    10"

    172.

    16'

    0"17

    9.6

    6' 2"

    188.

    16'

    4"19

    9.0

    Can

    you

    pre

    dict

    the

    wei

    ght o

    f a 5

    ’9”

    pers

    on fr

    om th

    is d

    ata?

  • Abou

    t rAb

    out r

    �C

    an y

    ou p

    redi

    ct th

    e w

    eigh

    t of a

    5’9

    ” pe

    rson

    from

    this

    dat

    a?

    Heigh

    tAve

    rage

    W

    eight

    5' 2"

    142.

    15''

    4"

    147.

    75'

    6"15

    6.0

    5' 8"

    164.

    35'

    10"

    172.

    16'

    0"17

    9.6

    6' 2"

    188.

    16'

    4"19

    9.0

    Sure

    , the

    dat

    a is

    pre

    dict

    able

    and

    is v

    ery

    linea

    r. B

    ydr

    awin

    g a

    line

    thro

    ugh

    the

    poin

    ts o

    n a

    grap

    h, w

    e ca

    npr

    edic

    t the

    wei

    ght o

    f the

    ave

    rage

    5’9

    ” m

    ale.

    Aver

    age

    Mal

    e W

    eigh

    t in

    Som

    ewhe

    revi

    lle

    130

    140

    150

    160

    170

    180

    190

    200

    210

    5' 2"

    5'' 4"

    5' 6"

    5' 8"

    5' 10"

    6' 0"

    6' 2"

    6' 4"

    Heig

    ht (f

    t/in)

    Weight (pds)

    5' 9"

    168.

    4

    168.

    4

  • Abou

    t rAb

    out r

    �W

    e ca

    n as

    sum

    e th

    at th

    e lin

    e w

    e dr

    ew th

    roug

    h th

    e po

    ints

    isa

    good

    indi

    cato

    r of r

    ealit

    y be

    caus

    e it

    lies c

    lose

    to e

    very

    poin

    t. r

    desc

    ribes

    how

    wel

    l the

    line

    des

    crib

    es th

    e tru

    e da

    ta(r

    ealit

    y).

    Heigh

    tAve

    rage

    W

    eight

    5' 2"

    142

    5'' 4

    "14

    85'

    6"15

    65'

    8"16

    45'

    10"

    172

    6' 0"

    180

    6' 2"

    189

    6' 4"

    199

    Aver

    age

    Mal

    e W

    eigh

    t in

    Hap

    pyvi

    lle

    130

    140

    150

    160

    170

    180

    190

    200

    210

    5' 2"

    5'' 4"

    5' 6"

    5' 8"

    5' 10"

    6' 0"

    6' 2"

    6' 4"

    Heig

    ht (f

    t/in)

    Weight (pds)

    5' 9"

    168.

    4Th

    is lin

    e is n

    o go

    od

    Neith

    er is

    this

    line

  • Abou

    t rAb

    out r

    �Le

    t’s lo

    ok a

    t som

    e ot

    her d

    ata.

    Thi

    s tim

    e w

    e w

    illco

    llect

    dat

    a on

    the

    num

    ber o

    f chi

    ldre

    n m

    en in

    Hap

    pyvi

    lle h

    ave.

    The

    resu

    lts a

    re sh

    own

    belo

    w�

    Can

    you

    pre

    dict

    how

    man

    y ch

    ildre

    n th

    e av

    erag

    e5’

    9” m

    an h

    as?

    Heig

    htAv

    erag

    e #

    of C

    hild

    ren

    5' 2"

    3.2

    5'' 4

    "5.

    35'

    6"3.

    85'

    8"2.

    05'

    10"

    6.1

    6' 0"

    3.3

    6' 2"

    1.9

    6' 4"

    4.3

  • Abou

    t rAb

    out r

    �C

    an y

    ou p

    redi

    ct h

    ow m

    any

    child

    ren

    the

    aver

    age

    5’9”

    man

    has?

    Heig

    htAv

    erag

    e #

    of

    Chi

    ldre

    n5'

    2"

    3.2

    5'' 4

    "5.

    35'

    6"

    3.8

    5' 8

    "2.

    05'

    10"

    6.1

    6' 0

    "3.

    36'

    2"

    1.9

    6' 4

    "4.

    3

    Aver

    age

    No. o

    f Chi

    ldre

    n in

    Som

    ewhe

    revi

    lle

    01234567

    5' 2"

    5'' 4"

    5' 6"

    5' 8"

    5' 10"

    6' 0"

    6' 2"

    6' 4"

    Heig

    ht (f

    t/in)

    Children

    Prob

    ably

    not

    , the

    dat

    a is

    unp

    redi

    ctab

    le b

    ecau

    se it

    is n

    ot li

    near

    . In

    fact

    it is

    not

    ord

    ered

    at a

    ll. I

    t wou

    ld b

    e di

    ffic

    ult f

    indi

    ng A

    NY

    line

    that

    com

    es c

    lose

    to a

    ll th

    e po

    ints

    . Thi

    s is t

    he b

    est f

    ittin

    g lin

    e --

    bar

    ely

    5' 9"

    3.7?�

  • Abou

    t rAb

    out r

    The

    abili

    ty fo

    r a li

    ne to

    clo

    sely

    fit th

    e da

    ta is

    its c

    orre

    latio

    nco

    effic

    ient

    , or

    r val

    ue.

    r is

    valu

    ed b

    etw

    een

    0 an

    d 1,

    0m

    eani

    ng N

    O c

    orre

    latio

    n an

    d 1

    mea

    ning

    per

    fect

    cor

    rela

    tion.

    Mos

    t sci

    entif

    ical

    ly d

    ata

    falls

    betw

    een

    the

    two.

    Aver

    age

    No. o

    f Chi

    ldre

    n in

    Som

    ewhe

    revi

    lle

    r = 0

    .132

    6

    01234567

    5' 2"

    5'' 4"

    5' 6"

    5' 8"

    5' 10"

    6' 0"

    6' 2"

    6' 4"

    Heig

    ht (f

    t/in)

    Children

    Aver

    age

    Weig

    htHe

    ight

    Aver

    age

    # of

    Child

    ren

    142

    5' 2"

    3.2

    148

    5'' 4

    "5.

    315

    65'

    6"3.

    816

    45'

    8"2.

    017

    25'

    10"

    6.1

    180

    6' 0"

    3.3

    189

    6' 2"

    1.9

    199

    6' 4"

    4.3

    Aver

    age

    Mal

    e W

    eigh

    t in

    Som

    ewhe

    revi

    lle

    r = 0

    ..998

    4

    130

    140

    150

    160

    170

    180

    190

    200

    210

    5' 2"

    5'' 4"

    5' 6"

    5' 8"

    5' 10"

    6' 0"

    6' 2"

    6' 4"

    Heig

    ht (f

    t/in)

    Weight (pds)

    Thus

    , we

    can

    say

    that

    ther

    e IS

    aco

    rrel

    atio

    nbe

    twee

    n he

    ight

    and

    wei

    ght,

    but t

    here

    isN

    OT

    a co

    rrel

    atio

    nbe

    twee

    n he

    ight

    and

    no. o

    f chi

    ldre

    n.

    stro

    ng c

    orre

    latio

    nw

    eak

    corr

    elat

    ion

  • �So

    wha

    t doe

    s thi

    s hav

    e to

    do

    with

    che

    mis

    try?

    �Th

    e am

    ount

    of W

    ürst

    er d

    ye p

    rodu

    ced

    from

    the

    DPD

    reag

    ent i

    s dire

    ctly

    pro

    porti

    onal

    toth

    e am

    ount

    of c

    hlor

    ine

    in th

    e sa

    mpl

    e. T

    heco

    lore

    d dy

    e is

    resp

    onsi

    ble

    for t

    he a

    bsor

    banc

    eat

    520

    nm.

    �Th

    us B

    eer’

    s law

    tells

    us t

    hat t

    he a

    bsor

    banc

    eof

    a sa

    mpl

    e w

    ith e

    xces

    s DPD

    will

    be

    dire

    ctly

    prop

    ortio

    nal t

    o th

    e am

    ount

    of c

    hlor

    ine

    in it

    .�

    We

    use

    r to

    chec

    k ho

    w w

    ell B

    eer’

    s law

    isw

    orki

    ng u

    nder

    spec

    ific

    labo

    rato

    ry c

    ondi

    tions

    .

    Abou

    tAb

    out rr