Determination of Nitrite and Nitrate in Drinking Water Using ... › 4189-AU132_Apr91_LPN034527 › 4189-AU132_Apr91_LPN034527PDFThe method is free from most ionic interfer- concentrate to 1000 mL with deionized water. ences due to the specificity of UV detec
Application Update
AU 132 April 1991
Determination of Nitrite and Nitrate in Drinking Water Using Ion Chromatography with Direct UV Detection INTRODUCTION
Eluent
The ion chromatographicanalysisof nitrite and nitrate in drinking water is accomplishedusing direct UV detectionof the analytes.The methodis free from most ionic interfer-
To prepare1.0L of eluent (1.8 mM sodiumcarbonate, 1.7 mM sodiumbicarbonate),dilute 10.0mL of eluent concentrateto 1000mL with deionizedwater.
encesdue to the specificity of UV detection.The methodis 11 drink ' 1 B 'd 1 I ' bl app ica e to a mg water sampes. romi e may a so be separatedfrom other ions and detectedusing this method.
Stock Standards 1000ppm Nitrite: Dissolve 1.499g NaN°2 in 1.0L of deionizedwater
The methodof chemically suppressedconductivity detection of nitrite and nitrate in drinking water (Dionex Application Update#131) is an alternativeto this method,Note that if the two methodsare combined,chemicalsuppressionwill yield additionalbenefitsin the determinationof nitrite and nitrate with UV detection.The useof a suppressor(AMMSII, Dionex PIN 043074)betweenthe column and the
WorkingStandards Dilute the stock standardsto concentrationlevels that bracketthe concentrationlevel of interest.Prepareworking standardsfrom the stock standardjust prior to analysis.
detectorcell reducesbackgroundabsorbanceand eliminates negativepeaks associate d Wi' th chIonde and suIf ate m . this o
CONDITIONS
method(seeFig. 3).
Column:
RECOMMENDED EQUIPMENT
Eluent:
IonPac@AS9analyticalcolumn with AG9 guard 1.8mMNa2CO3/1.7mMNaHCO3
Dionex Ion Chromatographwith a UV Nisible absorbance detector
Flow Rate: SampleVolume:
2.0 mL/min 25 ~
REAGENT ANDSTANDARD PREPARATION
Detection:
UV at 210 om, 0.2 AUFS
'
,
'
1000ppm Nitrate: Dissolve 1.371g NaN°3 in 1.0 L of deionizedwater
Sodiumcarbonate/ sodiumbicarbonateeluentconcentrate (PIN 039513) SodiumNitrite, ACS Grade SodiumNitrate, ACS Grade
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Dionex S.A. Dionex B.Y. Nippon Dionex K.K. Boulogne,France The Netherlands Yodogawa-ku,Osaka (I) 46216666 (076) 714800 (06) 8851213 LPN 034527 5M 4!91
looPacis a RegisteredTrademarkof Dionex Corporation
@Dionex Corporation
Column: Eluent: FlowRate: Detection:
lonPacAS9/AG9 1.7mMNaHCO3 1.8mHN~CO3 2.0ml/mln UV@210nin
Column: Eluent:
lonPacAS9/AG9 1.7mMNaHCO3 1.8mHN~CO3 FlowRate: 2.0ml/min Detection: UV@210nm Suppressor: AMMS-II
0.2 Peaks
1. Nitrite 3 ppm 2. Bromide 10ppm 3. Nitrate 10ppm
Peaks: 0.2000
1. Nitrite 3ppm 2. Bromide 10ppm 3. Nitrate 10ppm
3 3 A 1
AU 1
00.
n
"'"'
"V._~
0
~
0 Minutes
~
110
Minutes
FIGURE 1. DETERMINATION OF NITRITE AND NITRATE WITH DIRECT UV DETECTION
FIGURE 3. DIRECT UV DETECTION OF NITRITE AND NITRATE IN DRINKING WATER (PRESERVEDWITH SULFURIC ACID*) WITH CHEMICAL SUPPRESSIONOF ELUENT
Column: Eluent:
IonPac 1.7 mMAS9/AG9 NaHCO3
PERFORMANCE CHARACTERISTICS Th e detectlon . 1Imlt . .m . dn.nkin g water sarnp1es usmg . a 25
FI
2 1'0 8 mH l/ N~CO3
loop is 10 ppb for nitrite and 15 ppb for nitrate. This corre-
Rt
ow ae:
. m mm
Detection: UV@210nm Peaks:
1. Chloride40ppm
2. Nitrite
3 ppm
3. Bromide10ppm 4. Nitrate 10 ppm 5. Sulfate 1800ppm 0 4
2
Z
3
00.
Minutes
FIGURE 2. DIRECT UV DETECTION OF NITRITE AND NITRATE IN DRINKING WATER (PRESERVED WITH SULFURIC ACID*)
*Presently,the US EPA is evaluatingthe suitability of acid preservationasdescribedin EPA/570/9-90/008 DETERMINATION OF NITRITE AND NITRATE IN DRINKING WATER USING ION CHROMATOGRAPHY WITH DIRECT UV DETECTION
-~lIT
spondsto 3.0-ppbnitrogen asnitrite, and 3.5-ppbnitrogen as nitrate. The methodis linear for nitrite over the range 10ppb 50 .." . ppm. It IS Imear lOr mtrate over the range of 15 ppb to 75 ppm. to
