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The use of lens masks to improve sensitivity in atomic absorption spectrophotometry
Amdylica
The use of lens masks to improve spectrophotometry absorption
sensitivity
Chimico
Ado
in atomic
tllc atom distrihtion in a laminar-flow airRASc’N ,\sl) Hwrr3f.sI invcstigatctl nntl found ;I con.siclerablc concentri~tion of atoms flame for twclvc clcmcnts, ;Lt tllc centrc of tlic flame. Tliey showed tllilt tlic sensitivity of atomic iLl>SorptiOn cc:uld Ix improved for scvoral clemcnts by using il pinlwlc milsk wit11 il I-mm apcrturc. as IXLrt Of tile flame. I-Iowcvcr, tllc x-mm tllc liglit I>‘atll is rcstrictccl to tllc “atom-rich” nl;lsk cut off ;Lpprosimatcly (19“I ,” of tlw incident light, pjving a poor signal-to-noise of tllc nitrous oXi&-iKctylcne ratio. _JA~VOI~OWSKIcd al.?, in an Cilrly invcstigiLti0ll flnmc, illSO used a l~inl~olc ap3-turc in 8 study of cliromiurn and vanadium. Tliey found no incrcasc in scnsitivit)* for tlicsc elements, and csplnincd tliis as Iwing clue to tlic n;~t~ow nitrous ositlc-acet>*lcnc flame itnd tllc cliffwcnt opticill system of their PcrkinElmer instrument. However, SI~RACUE AKJ) SJAVJN” noted tllilt ;L single mask is USCC~ on tllc Pa-kin-Elmer motlcl 30.73, to limit tlw six of tllc ol>tical I>ciim through tllc flilme, ‘I‘hc 13or,rsc; burner‘1 is clcsipwd ittltl tliat tliis increases sensitivity for nzolylxlenuni. iL IiUger crossto improve sensitivity by prcscnting a wider fliLIllC ;mtl tliercforc scctiond 8rciL of atom-rid1 flnmc to tlic detector. SI*J(AG~:B h;\;J) SLAVISH cIidnwtl incrwscs in sensitivity of up to rooo/o for calcium, cllromium and mol~btlcJ1um in tlic ilir--ilCCtylCr?C fl:LlllC, using tliis burner 011 iI Pcrlcin-Elmer rncdcl 303.
ilWtJ’lCnC
Tl1is conununici~tion that :L simple i~rr;~ngcrncnt lllilny dctcrmiJiiit ions.
confir_Jns of masks
IL\SS hNI) I-L~~JI~J.~‘~ can give si@Iifici~Jltl~
finding, ilntl dcmonstr:ltcs improved sciisitivit~’
for
Zllstrlfrric~i(riliorr. A Tcclitron niodcl AAg iLt0llliC iLl)Sor])tio~~ spxtronwtcr, fittccl wit11 CL.Jarrell-Asll i mctcr IS wcrc neon-fillccl. IIzfrzzcrs. Tcchtron titanium groovccl burners wcrc usccl, iLS sllown in ‘I’ablc I. Solt~tious. Ill most Ci\SCS tlic solutions were prcprcd from tlic prc IllCti~l, ant1 wcrc prcscnt as tlic cliloriclc in 2 o/oliyclrocliloric iKid. Gold, silver, pli\tinum ant1 IalliKlil1~~~wcrc in IonjO liyclrocl~loric ilCiC1; ICilCl mid nicrcury wcrc in 2’y0 nitric acid.
us1: 01’ IIUI~SI~I
.-- -.-.-. fclt~~/ll
(IllIN)
A 1350
bo
,\ 135 I
I 00
AH52
100
-_-
--
A tcctl. Clbijri. Acln,
--.--_Slot
.._. -_ rvitlllr
(?l1lll)
_--._.
--_
..-__---_.-
-.._..--
_Ahbrrvioliorr
~IICS
_-_._
Sitrow
I .o
132-19.1
f:ltc
-. ----~
0.5 0.5
53 (1971)
.-_.-._.
.~---
itr
‘I’tcDlc
i*;Oh
oxiclc/;rcctylcnc
r\ir’/acct~lcnc
A A
hir/lrpclrogcn Nitrc)J;crl/hyclro~~~~/~I~tr;\itlctl Air/nlctllyl isohtyl Itctonc --
I\ 1.I s 1.1r\ XII\
air
I I
SHORT TABLE A
COhtWJNICATIONS
II
CObIPhRISON
OF
--_-
--._
328.07 309.27 2‘12.30
Cr
SENSITIVITIES
(n1.4)
(11m)
T3a Bi Ca. Cd CO
553.55 223.06
-.
_--
______-__
15, 10 ::
I0 5
422.67
Fc Ga
._.__
WITI-IOUT
meat
LENS
r)lUSl
-____-.__-
_.__.___.__
-_.__.----
0.05 1 I .07
0.0+7
0.5 2.0 2 .5
0.28
0. ;r3
0.0-13 2.16
0.*39
I 1
I.87
21
2.5
0.37 O.O.{‘Z
0.32
0.036 0.111
0.034 0.100 0.27
0.5
2.5
2.5
9
1.02
5 18
’ 4
0.028
50 6
357.y7
15 10
0.5 5.0 ‘2. 5
0.3.t 0. I OG 0.128
0.
0.5 0.5 2.5 ‘2. 5
0.079
o.o71
I I
O.l8_t
O.lc-jI
‘4
O.W$i
16 1I
I .CJ 2.5
* *43 I .I 0 1.3, 3.H.1 2.03 O..iH o.c>052 0.056
324.75 2qH.33 287.42
5 5
I0 I0 10
265.16
to
)-lg
253.65
In Mg Mn
3o3.m 285.21 279.48
3 3 5 1C) IO I0
MO
313.26
IO LO
232.00
1% I’d I’t Sb SC
217.00 2.l‘l.Z’) 2G5.95 217.58 196.03
Si Sn
251.61 2 2 ‘& .6 I
IO IO IO 10 TO 10 I5 *5 IO I 0 10 IO
460.73 214.28 364.27 318.40 213.W
IO 10 15
I0 IO
_--.__ . --_-___
Cl ..5
0.1
2.5 0.5 5.0
1.o 0.5 2.5 2.5 5.0 2.5
I.1
I
3s 13
I .oo I .IH 3 . ‘20 I .?Z 0..(1
0.005C~ 0.050
5 I:! 18
0.126
0.107
0.34 0:z.i 0.07s 0.2 L 0.1 s oar31 I .I2 0.3H
35 ‘23 18 G 18
18
0.1’23
0.4-i 0. I ., 3 1 *.I” I.14 Z.HL 0. I 9 0.100
O.O<))L O.‘Z.} 0.21 0.
I _=jI
1.2’1 O..$.?
6.0
2.5 2.5
3.4 I
1.22
5.0 2.5 2.5
0.22
0.27
0.2.1
5.0 5.0 0.5
3.17 0.71
‘*75 o.G5 0.0:
0.012
-.-.--.--_------
2.! ri, II 20 18 1.5
1.17
0..#6
0.56 0.160 2.17
__--_- _.._._-. -
‘3
0.p
0. rg
0.5 0.5 0.5 0.5 0.5 2.5 2.5 5.0
I I 2x
0.077
0.50
mThe burner height is Incnsurcd as the clistancc bctwccn which the burner top starts to intcrccpt the light bc:rm. = lcnn; M = nwtlium; R rich; VR x-cry rich. “L c pg ml-1 for I o/0 absorption.
1fj 9 II 12
52 7 21 13 23 ‘5 *5 II
I
4
----- ---.-l_l.--.-I-Ithe
lmrncr
top
:lIId
tlIc
optical
path,
i.e.,
the point
amE disczissio7t The lens masks have been used on Techtron instruments (models AA4 and AAg) fw the past two years in the routine analysis of mining and metallurgical samples, and have provided some improvement in sensitivity for every element and in every
Xewlts
..r6..
Y.IASKS
0.5
cc
Sr Tc Ti V zn
(nrm)
AND
5 15
IO
Ni
WIT11
22S.80 2.10.73
10
CU
I93
at
SHORT COMMUXIChl‘IONS
=94 f]anlc
illvcstigiLtc(l
yj’:&.
\Vitll
(‘l’ill>lC! 11). ‘I’liis improwmcnt may IX! ;1S low as s’;/,, hut CiLtl I,c in tile &sign of Il0l10\V-c.2tl~0clc lamps, tlie problems of and, in pat?icUliW, tllc fact tliat most lamps poor signid-to-noise ratio arc not serious, ]l:lVc cirt]lOtlc!j of Icss tllan 4 mm tliiUtlctcr IYlCiLnStllat tllcre is considcral~ly less attcIlu:ltion \\*llcn Inasks ;Lrc USCA than \V;LS tlw ciLSC with IO-mm catllodcs. Typically, t\vo 6-nml dii~tlwtcr IellS UlilSkS trimsrnit 50’:: of tllc Siglld rcccivetl wit]1 no masks in position. Alignment 0l tllc Il~~11~~~V-ci~tll~~~~ lamps dOC!S become mOre criticid, but tllis CiLIl 1x2 ovcrconw I>y moclif~~ing tile 1w-q~ turret on tile instruments to CniLhle p-ccisc aliginicnt in tllc vcrtiCiL1 ilntl Iiorizc~nt~~l plants.
(Iicccivccl
rcccnt
July
Photometric arsenazo I I I
XlVilnC(!S
zoth,
1970)
determination
of micro
amounts
of calcium
with
Arscnnzo I1 I (r,8-dil~yclrc~syiia]~litli~~l~iic-3,(,-~l~~l~Oni~ ;IciisC(~~o-z)]~llcIlyli~rSOniC acicl]) rcilCtS wit11 lllitny nictnllic ions t0 Iorin very StiLl>lC! higlily CoIourccl iiincr-cwilplcs Salts. ‘I’llc rcagcnt IliP+ Ixxn widely applied in tllc slxctrolAlotometric dctcrniinntioii of llcavy IllC!tillS sucli as U, ‘1‘11, %r, etc., but its reactions witli di- ilIlCl trivnlcnt liglkt IIlCt:LlS IlilVC! I>CCn less studied. In tllc work clcscrilx?cl Im-c, it WCIS found tll;Lt ilrscniizo III fornwtl iL I>Luc I : I ~onlplcs wit11 calciunl(lL). l’llc hsurl>i~ncc spxtrunl sllowcd two maxima at 59)5-GOO Ill11 ant1 650-055 nin. In tllc pH rilIlgC stucliccl (3-lo), masimum alxorbnncc \VilS ohscrvccl at 1x1 0, ;incl tlic sensitivity \VilS cxccllcnt, but bcttcr sclcctivity was found at ])H s-6. Slllilll ~lmou~lts ol calciuin(I1) coulcl tllcn lx clctcriiiinccl in tllc prcsencc of IOO-fOlt1 amounts Ot ~TlilgIlCsiUln( I I) XllCl ~llilll~iLllCSC(I I) ; ttle IllCtllOCl \Vi\S ilppliCC\ for tllc mxilysis (II inngncsitc.
/I YSCILGO III solr~lio~u. All i~ClLlCOUSIO- :) ;\I solution was prcpnrcd by weighing tile rcilgcllt (1:luka). Its actual concentration was dctcrrninccl to 1~ 0.73 *IO-~ M by t11c t11etl1otl or Xl~~1Ol~I~Uli’. Calcirlm chloride sohilion. A x0-~ M solution WilS lx-elxu-ccl by dissolving Calcium carbonate (Sl~~ri~~g-l(i~l~lbi~u~n, l>.iL.) in reagent-grade Ilydroclhric acid; it \vi\S stmnclarclizcd conq~lesinictrically.
The use of lens masks to improve spectrophotometry absorption
sensitivity
Chimico
Ado
in atomic
tllc atom distrihtion in a laminar-flow airRASc’N ,\sl) Hwrr3f.sI invcstigatctl nntl found ;I con.siclerablc concentri~tion of atoms flame for twclvc clcmcnts, ;Lt tllc centrc of tlic flame. Tliey showed tllilt tlic sensitivity of atomic iLl>SorptiOn cc:uld Ix improved for scvoral clemcnts by using il pinlwlc milsk wit11 il I-mm apcrturc. as IXLrt Of tile flame. I-Iowcvcr, tllc x-mm tllc liglit I>‘atll is rcstrictccl to tllc “atom-rich” nl;lsk cut off ;Lpprosimatcly (19“I ,” of tlw incident light, pjving a poor signal-to-noise of tllc nitrous oXi&-iKctylcne ratio. _JA~VOI~OWSKIcd al.?, in an Cilrly invcstigiLti0ll flnmc, illSO used a l~inl~olc ap3-turc in 8 study of cliromiurn and vanadium. Tliey found no incrcasc in scnsitivit)* for tlicsc elements, and csplnincd tliis as Iwing clue to tlic n;~t~ow nitrous ositlc-acet>*lcnc flame itnd tllc cliffwcnt opticill system of their PcrkinElmer instrument. However, SI~RACUE AKJ) SJAVJN” noted tllilt ;L single mask is USCC~ on tllc Pa-kin-Elmer motlcl 30.73, to limit tlw six of tllc ol>tical I>ciim through tllc flilme, ‘I‘hc 13or,rsc; burner‘1 is clcsipwd ittltl tliat tliis increases sensitivity for nzolylxlenuni. iL IiUger crossto improve sensitivity by prcscnting a wider fliLIllC ;mtl tliercforc scctiond 8rciL of atom-rid1 flnmc to tlic detector. SI*J(AG~:B h;\;J) SLAVISH cIidnwtl incrwscs in sensitivity of up to rooo/o for calcium, cllromium and mol~btlcJ1um in tlic ilir--ilCCtylCr?C fl:LlllC, using tliis burner 011 iI Pcrlcin-Elmer rncdcl 303.
ilWtJ’lCnC
Tl1is conununici~tion that :L simple i~rr;~ngcrncnt lllilny dctcrmiJiiit ions.
confir_Jns of masks
IL\SS hNI) I-L~~JI~J.~‘~ can give si@Iifici~Jltl~
finding, ilntl dcmonstr:ltcs improved sciisitivit~’
for
Zllstrlfrric~i(riliorr. A Tcclitron niodcl AAg iLt0llliC iLl)Sor])tio~~ spxtronwtcr, fittccl wit11 CL.Jarrell-Asll i mctcr I
us1: 01’ IIUI~SI~I
.-- -.-.-. fclt~~/ll
(IllIN)
A 1350
bo
,\ 135 I
I 00
AH52
100
-_-
--
A tcctl. Clbijri. Acln,
--.--_Slot
.._. -_ rvitlllr
(?l1lll)
_--._.
--_
..-__---_.-
-.._..--
_Ahbrrvioliorr
~IICS
_-_._
Sitrow
I .o
132-19.1
f:ltc
-. ----~
0.5 0.5
53 (1971)
.-_.-._.
.~---
itr
‘I’tcDlc
i*;Oh
oxiclc/;rcctylcnc
r\ir’/acct~lcnc
A A
hir/lrpclrogcn Nitrc)J;crl/hyclro~~~~/~I~tr;\itlctl Air/nlctllyl isohtyl Itctonc --
I\ 1.I s 1.1r\ XII\
air
I I
SHORT TABLE A
COhtWJNICATIONS
II
CObIPhRISON
OF
--_-
--._
328.07 309.27 2‘12.30
Cr
SENSITIVITIES
(n1.4)
(11m)
T3a Bi Ca. Cd CO
553.55 223.06
-.
_--
______-__
15, 10 ::
I0 5
422.67
Fc Ga
._.__
WITI-IOUT
meat
LENS
r)lUSl
-____-.__-
_.__.___.__
-_.__.----
0.05 1 I .07
0.0+7
0.5 2.0 2 .5
0.28
0. ;r3
0.0-13 2.16
0.*39
I 1
I.87
21
2.5
0.37 O.O.{‘Z
0.32
0.036 0.111
0.034 0.100 0.27
0.5
2.5
2.5
9
1.02
5 18
’ 4
0.028
50 6
357.y7
15 10
0.5 5.0 ‘2. 5
0.3.t 0. I OG 0.128
0.
0.5 0.5 2.5 ‘2. 5
0.079
o.o71
I I
O.l8_t
O.lc-jI
‘4
O.W$i
16 1I
I .CJ 2.5
* *43 I .I 0 1.3, 3.H.1 2.03 O..iH o.c>052 0.056
324.75 2qH.33 287.42
5 5
I0 I0 10
265.16
to
)-lg
253.65
In Mg Mn
3o3.m 285.21 279.48
3 3 5 1C) IO I0
MO
313.26
IO LO
232.00
1% I’d I’t Sb SC
217.00 2.l‘l.Z’) 2G5.95 217.58 196.03
Si Sn
251.61 2 2 ‘& .6 I
IO IO IO 10 TO 10 I5 *5 IO I 0 10 IO
460.73 214.28 364.27 318.40 213.W
IO 10 15
I0 IO
_--.__ . --_-___
Cl ..5
0.1
2.5 0.5 5.0
1.o 0.5 2.5 2.5 5.0 2.5
I.1
I
3s 13
I .oo I .IH 3 . ‘20 I .?Z 0..(1
0.005C~ 0.050
5 I:! 18
0.126
0.107
0.34 0:z.i 0.07s 0.2 L 0.1 s oar31 I .I2 0.3H
35 ‘23 18 G 18
18
0.1’23
0.4-i 0. I ., 3 1 *.I” I.14 Z.HL 0. I 9 0.100
O.O<))L O.‘Z.} 0.21 0.
I _=jI
1.2’1 O..$.?
6.0
2.5 2.5
3.4 I
1.22
5.0 2.5 2.5
0.22
0.27
0.2.1
5.0 5.0 0.5
3.17 0.71
‘*75 o.G5 0.0:
0.012
-.-.--.--_------
2.! ri, II 20 18 1.5
1.17
0..#6
0.56 0.160 2.17
__--_- _.._._-. -
‘3
0.p
0. rg
0.5 0.5 0.5 0.5 0.5 2.5 2.5 5.0
I I 2x
0.077
0.50
mThe burner height is Incnsurcd as the clistancc bctwccn which the burner top starts to intcrccpt the light bc:rm. = lcnn; M = nwtlium; R rich; VR x-cry rich. “L c pg ml-1 for I o/0 absorption.
1fj 9 II 12
52 7 21 13 23 ‘5 *5 II
I
4
----- ---.-l_l.--.-I-Ithe
lmrncr
top
:lIId
tlIc
optical
path,
i.e.,
the point
amE disczissio7t The lens masks have been used on Techtron instruments (models AA4 and AAg) fw the past two years in the routine analysis of mining and metallurgical samples, and have provided some improvement in sensitivity for every element and in every
Xewlts
..r6..
Y.IASKS
0.5
cc
Sr Tc Ti V zn
(nrm)
AND
5 15
IO
Ni
WIT11
22S.80 2.10.73
10
CU
I93
at
SHORT COMMUXIChl‘IONS
=94 f]anlc
illvcstigiLtc(l
yj’:&.
\Vitll
(‘l’ill>lC! 11). ‘I’liis improwmcnt may IX! ;1S low as s’;/,, hut CiLtl I,c in tile &sign of Il0l10\V-c.2tl~0clc lamps, tlie problems of and, in pat?icUliW, tllc fact tliat most lamps poor signid-to-noise ratio arc not serious, ]l:lVc cirt]lOtlc!j of Icss tllan 4 mm tliiUtlctcr IYlCiLnStllat tllcre is considcral~ly less attcIlu:ltion \\*llcn Inasks ;Lrc USCA than \V;LS tlw ciLSC with IO-mm catllodcs. Typically, t\vo 6-nml dii~tlwtcr IellS UlilSkS trimsrnit 50’:: of tllc Siglld rcccivetl wit]1 no masks in position. Alignment 0l tllc Il~~11~~~V-ci~tll~~~~ lamps dOC!S become mOre criticid, but tllis CiLIl 1x2 ovcrconw I>y moclif~~ing tile 1w-q~ turret on tile instruments to CniLhle p-ccisc aliginicnt in tllc vcrtiCiL1 ilntl Iiorizc~nt~~l plants.
(Iicccivccl
rcccnt
July
Photometric arsenazo I I I
XlVilnC(!S
zoth,
1970)
determination
of micro
amounts
of calcium
with
Arscnnzo I1 I (r,8-dil~yclrc~syiia]~litli~~l~iic-3,(,-~l~~l~Oni~ ;Ici
/I YSCILGO III solr~lio~u. All i~ClLlCOUSIO- :) ;\I solution was prcpnrcd by weighing tile rcilgcllt (1:luka). Its actual concentration was dctcrrninccl to 1~ 0.73 *IO-~ M by t11c t11etl1otl or Xl~~1Ol~I~Uli’. Calcirlm chloride sohilion. A x0-~ M solution WilS lx-elxu-ccl by dissolving Calcium carbonate (Sl~~ri~~g-l(i~l~lbi~u~n, l>.iL.) in reagent-grade Ilydroclhric acid; it \vi\S stmnclarclizcd conq~lesinictrically.