Low-concentration Nutrient Determination Needs and ChallengesWhich - - PowerPoint PPT Presentation

Low-concentration Nutrient Determination Needs and Challenges—Which Ones? Needs and Challenges Which Ones? How Low? What Applications?

Charles J. Patton1 and William Lipps2

1 U.S. Geological Survey

National Water Quality Laboratory P.O. Box 25585, Denver, Colorado 80225-0585

2 ITT | OI Analytical

ITT | OI Analytical College Station, TX 77842-9010 Tuesday, August 16 2011 NEMC, Bellevue, WA

Challenges in Low-concentration Nutrient Analyses

Speakers for Challenges of low concentration nutrient analysis Speakers for Challenges of low-concentration nutrient analysis morning and afternoon sessions

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

 Analytical service laboratory  Prod ction sample processing

30 000 samples/ ear

 Production sample processing ~ 30,000 samples/year,

~ 1.5 x 106 determinations

 Quality Assurance/Quality Control

2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

 New methods development including laboratory automation

Overview of Overview of Yearly of Yearly of Nutrient Nutrient Concentrations in Concentrations in Surface Water and Surface Water and Groundwater Groundwater in the United States in the United States Groundwater Groundwater in the United States in the United States

 Nitrogen- and Phosphorus-containing  Nitrogen- and Phosphorus-containing Nutrients

– Filtered, Undigested – Filtered, Digested – Whole-water, Digested

 Detection limits  Detection limits  Laboratory blanks  Blind blanks  Field blanks

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

 Field blanks

Differences in concentration distributions for different water Differences in concentration distributions for different water types

100

Surface water n = 7 000

1 4 3.2 9.9 3.4 7.7 21.6 10

(mg-N/L)

Surface water, n = 7,000 Groundwater, n = 2,884

0.17 0.5 1.4 0.9 0 1 1

centration (

0.02 0.01 0.03 0.01 0.1

itrate Conc

0.001

10th 25th Median 75th 90th 99th N

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

Percentile Percentile Percentile Percentile percentile

NWQL Di NWQL Di l d N N t i t A A l i i 2010 2010 NWQL Di NWQL Disso ssolve ved N d Nutrien ent A t Ana nalyses yses i in 2010 2010

15,000

13,050 11,029 12,705 13,296

12,500

QL in 2010 All results In-range < MDL Off-scale

0.004 - 0.20 mg-P/L

7,500 10,000

at the NWQ

0.01 - 0.80 mg-N/L 0.02 - 5.00 mg-N/L 0.001 - 0.20 mg-N/L

4,081

4751 (37%) 6231 (48%) 5,000

s Analyzed a

0.008 - 1.00

1996 (15%) 1368 (34%) 2291 (21%) 2,500

Samples

mg-N/L Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

Ammonium Nitrate Low-level Nitrate Nitrite Orthophosphate

NWQL Dissolved and Total Nitrogen Analyses in 2010

6,692

7 000

All results

0 05 5 0

6,000 7,000

WQL in 2010 All results In-range < MDL Off-scale

0.05 - 5.0 mg-P/L 4,053 4,704 3,397

4,000 5,000

d at the NW

0.05 - 5.0 mg-N/L 0.05 - 5.00 mg-N/L 0.05 - 5.0 mg N/L

323 476 307 706 2,000 3,000

les Analyze

mg-N/L

323 (5%) 476 (14%) 307 (7%) 706 (17%) 1,000

Alk li P lf t Alk li P lf t Di l d Kj ld hl T t l Kj ld hl

Samp

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

Alkaline Persulfate Digestion DN Alkaline Persulfate Digestion TN Dissolved Kjeldahl Nitrogen (DKN) Total Kjeldahl Nitrogen (TKN)

NWQL Dissolved and Total Phosphorus Analyses in 2010

8,452

9,000

All results

7,500

WQL in 2010

All results In-range < MDL Off-scale

0.004 - 0.20 mg-P/L 4,316

4,500 6,000

d at the NW

0.02 - 2.00 mg-P/L 0 003 0 20 1 554 2,146 2,482 163 (7%) 368 (17%) 1137 (13%) 1,097 (25%)

3,000

es Analyzed

0.01 - 2.00 mg-P/L 0.003 - 0.20 mg-P/L 1,554 536 (7%) (17%) 220 (14%) 254 (47%) (13%) (25%)

1,500

Sample

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

• Alk. Persulfate

Digestion DP

• Alk. Persulfate

Digestion TP Acid Persulfate Digestion DP Acid Persulfate Digestion TP Kjeldahl Digestion DP Kjeldahl Digestion TP

NWQL A i A l 2010(Di t A l ) NWQL Ammonium Analyses 2010(Discrete Analyzer)

0.04

L)

DA S li l t /H hl it NH

+ N

th d

0.03

(mg-N/L

DA Salicylate/Hypochlorite NH4

+-N method 95% 5% 95% 95% 95%

0.01 0.02 n = 567 n = 52 n = 77

ntration

n = 75

5% 95% 5% 5%

0.00

m Concen

5%

• 0.02
• 0.01

monium

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

MDL Calibrant Lab Blank Blind Blank Field Blank

Am

NWQL Nitrite Analyses 2010 (Discrete Analyzer)

0.0035

L)

95%

0.0025 0.0030

(mg-N/L

n = 74

DA NO2

• -N method

5%

0.0015 0.0020 n = 545

tration (

95% 95% 95%

0.0005 0.0010 n = 52 n = 74

Concent

5% 5% 5%

• 0.0005

0.0000

Nitrite C

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

MDL Calibrant Lab Blank Blind Blank Field Blank

• 0.0010

N

Relationship between nitrate + nitrite and nitrite Relationship between nitrate nitrite and nitrite concentrations analyzed at the NWQL in 2010

2.25 1.75 2.00

• N/L)

WG: Nitrite ≥ 0.05 mg-N/L. n = 45 WS: Nitrite ≥ 0.05 mg-N/L. n = 425 LC 3156 dilution limit LC 3157 dilution limit 1.25 1.50

ntration (mg-

0.50 0.75 1.00

Nitrite Conce

0.00 0.25 0.50 0 1 1 10 100

N

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

0.1 1 10 100

Nitrate + Nitrite Concentration (mg-N/L)

NWQL Standard-level Nitrate Analyses 2010 (Continuous- NWQL Standard level Nitrate Analyses 2010 (Continuous flow Analyzer) L)

St d d l l CdR NO

• N

th d

0.06 0.08

n (mg-N/L

221

Standard-level CdR NO3 -N method

95% 5%

0.04 0.06

centration

n = 221

95% 95% 95%

0.02 n = 433 n = 221 n = 221

rite Conc

5% 5% 5%

0.00

rate + Nit

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

MDL Calibrant Lab Blank Blind Blank Field Blank

• 0.02

Nitr

NWQL Low-level Nitrate Analyses 2010 Analyses 2010 NWQL Low level Nitrate Analyses 2010 Analyses 2010

(Continuous-flow Analyzer)

0.025

)

95%

0.020

(mg-N/L)

n = 61

Low-level CdR NO3

• -N method

5% 95%

0 010 0.015 n = 204

centration

95% 95%

0.005 0.010 n = 52 n = 119

trite Conc

5% 5% 5%

0.000

rate + Nit

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

MDL Calibrant Lab Blank Blind Blank Field Blank

• 0.005

Nit

Cadmium reactors are easily incorporated Cadmium reactors are easily incorporated into continuous flow analyzers

CFA

Debubbler Air Cadmium Reactors Air Complexing Buffer Sample (NO3

• )

NO2

• Complexing Buffer

NO2

• Sample (NO3
• )

FIA

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

Discrete analyzer nitrate reductase (AtNaR2) nitrate assay ( 37°C)—now USGS approved

3 2 2

( 7;30 C) pH

NaR

NO NADH H NO NAD H O

   



     



Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

CFA cadmium CFA cadmium reduction and DA reduction and DA enzyme enzyme reduction nitrate reduction nitrate CFA cadmium CFA cadmium-reduction and DA reduction and DA enzyme enzyme-reduction nitrate reduction nitrate concentration data concentration data pairs plotted about pairs plotted about the the line of line of equal relation equal relation

100 10

n (mg-N/L)

Surface water (Medium Code = WS) Groundwater (Medium Code = WG) Artificial matrix sample (Medium Code = OA) Interstitial water sample (Medium Code = WI) Surface-water QA sample (Medium Code = WSQ)

5.0 mg-N/L 25 mg-N/L 1

Concentration

Groundwater QA Sample (Medium Code = WGQ) Line of equal relation for CFA-CdR and DA-AtNaR2 methods Interim Reporting Limit (IRL) Set point for automatic 1+4 dilution Set point for prompt to enter a larger dilution factor

0 1

R2 Nitrate C

Set point for prompt to enter a larger dilution factor

0.04 mg-N/L Regression Parameters y = 1.0004x - 0.0092 0 01 0.1

DA AtNa

Kone run # 0134B on May 14, 2008

y 1.0004x 0.0092 r2 = 0.9998 n = 101

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

0.01 0.01 0.1 1 10 100

CFA CdR Nitrate Concentration (mg-N/L)

CFA d CFA d i d t d ti d i d DA d t d ti l i l l l l l i it t CFA CFA ca cadmium-re um-reduc ucti tion

• n an

and DA d DA enzyme-re enzyme-reduc ucti tion

• n l

low-

• w-leve

evel l nit itra rate concentration data concentration data pairs plotted about the pairs plotted about the line line of

• f equal relation

equal relation

1

Nitrate )

0.1

DA-AtNaR2 N tion (mg-N/L

Linear regression, all data y = 1.030 x + 0.002 0.01

w-level (LL) D Concentrat

Surface water Groundwater Blind blanks 0.001 0 001 0 01 0 1 1

Low

Line of equal relation NWQL LL CFA-CdR MDL and LL DA-AtNaR2 IRL

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

0.001 0.01 0.1 1

Low-level (LL) CFA-CdR Nitrate Concentration (mg-N/L)

NWQL 2010 Alkaline-persulfate-digestion Dissolved Nitrogen NWQL 2010 Alkaline persulfate digestion Dissolved Nitrogen (Continuous-flow Analyzer; determined as nitrate)

0.075

/L)

95%

0.050

(mg-N/

n = 196

Alkaline Persulfate Digestion DN

5% 95% 95% 95%

0 000 0.025 n = 203 n = 52 n = 196

ntration

5% 5%

• 0.025

0.000

Concen

5%

• 0.050

trogen C

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

MDL Calibrant Lab Blank Blind Blank Field Blank

• 0.075

Nit

NWQL Kjeldahl Nitrogen 2010 (ammonium + organic nitrogen; NWQL Kjeldahl Nitrogen 2010 (ammonium organic nitrogen; continuous-flow analyzer; determined as ammonium)

0.175

/L)

95%

0.125 0.150

(mg-N/

n = 181

Kjeldahl Digestion DN

5% 95%

0 050 0.075 0.100 n = 77 n = 52 n = 362

ntration

95% 95% 5%

0.000 0.025 0.050

Concen

5% 5% 5%

• 0.050
• 0.025

itrogen

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

MDL Calibrant Lab Blank Blind Blank Field Blank

• 0.075

Ni

NWQL Orthophosphate Analyses 2010 (Discrete Analyzer) )

0.010

(mg-P/L

0 007 0.008 0.009 75

DA orthophosphate (SRP) method

entration

95% 5%

0.005 0.006 0.007 n = 568 n = 75

us Conce

% 95% 95% 95%

0.002 0.003 0.004 n = 568 n = 52 n = 75

hosphoru

5% 5% 5%

0.000 0.001 0 00

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

P

MDL Calibrant Lab Blank Blind Blank Field Blank

• 0.001

Murphy Murphy & & Riley phos Riley phosphate assay phate assays need sodium lauryl need sodium lauryl Murphy Murphy & & Riley phos Riley phosphate assay phate assays need sodium lauryl need sodium lauryl sulfate (SLS) even on discrete analyzer platforms sulfate (SLS) even on discrete analyzer platforms

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

NWQL Low-level DP 2010 (Continuous-flow Analyzer)

0.004

95%

0.003

mg-P/L)

n = 96

Acid Persulfate Digestion DP

5% 95% 95% 95%

0 001 0.002 n = 149 n = 50 n = 96

ntration (

95%

0.000 0.001

s Concen

5% 5% 5%

• 0.001

hosphoru

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

MDL Calibrant Lab Blank Blind Blank Field Blank

• 0.002

Ph

NWQL Low-level TP 2010 (Continuous-flow Analyzer)

0.006

A id P lf Di i TP

0.004

n = 308

mg-P/L)

n = 188

Acid Persulfate Digestion TP

95% 5% 95% 95% 95%

0.002

n 308 n = 52 n = 188

ntration (

n 188

5% 5% 5%

0.000

us Concen

• 0.002

hosphoru

Samples amended with H2SO4 at collection sites

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

MDL Calibrant Lab Blank Blind Blank Field Blank

• 0.004

Ph

NWQL Alkaline-persulfate-digestion DP 2010 (Continuous-flow NWQL Alkaline persulfate digestion DP 2010 (Continuous flow Analyzer; determined as orthophosphate)

/L)

0 020 0.025 0.030

n (mg-P/

n = 114

Alkaline Persulfate Digestion TP

95% 95% 95%

0.010 0.015 0.020 n = 40 n = 52 n = 228

entration

5% 95% 95% 95%

0.000 0.005

s Conce

5% 5% 5%

0 015

• 0.010
• 0.005
• sphoru

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

MDL Calibrant Lab Blank Blind Blank Field Blank

• 0.015

Pho

NWQL Kjeldahl Phosphorus 2010 (Continuous-flow analyzer; NWQL Kjeldahl Phosphorus 2010 (Continuous flow analyzer; determined as orthophosphate)

/L)

95%

0.06

n (mg-N

n = 181

Kjeldahl Digestion DP

95% 5%

0.04 n = 55

centration

95% 95% 95%

0.02 n = 52 n = 144

us Conc

5% 5% 5%

0.00

hosphor

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

MDL Calibrant Lab Blank Blind Blank Field Blank

• 0.02

Ph

NWQL D t ti li it NWQL Detection limit summary

 Nitrite: 2 μg NO2

• -N/L

– With lower calibration range, reagent and field blank limited at about 0.5 ppb

 Orthophosphate (SRP): 4 μg PO4

3--P/L

– 2 μg PO4

3--P/L w/ SLS in acidic molybdate/antimony reagent; reagent and field blank limited at

about 1 ppb)

 Acid-persulfate-digestion DP and TP: 2 μg-P/L  Acid-persulfate-digestion DP and TP: 2 μg-P/L

– With lower-P persulfate reagent, perhaps 1 ppb before field blank limited

 Alkaline-persulfate-digestion DP and TP: 10 μg-P/L

– Lower-P persulfate reagent needed

 Kjeldahl-digestion DP and TP: 20 μg-P/L j g μg

– Reagent blank limited

 Ammonium: 10 μg NH4

+-N/L

– Field and reagent blank limited

 Standard- (low-) range Nitrate: 20 (10) μg NO3

• -N/L

– Field and reagent blank limited at about 5 ppb

 Alkaline-persulfate-digestion DN and TN: 20 μg-N/L

– If nitrate could be removed prior to digestion to permit lower calibration range and lower-N persulfate reagent used, field and reagent blank limit at about 5 ppb

 Kjeldahl-digestion nitrogen: 50 μg-N/L

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses

 Kjeldahl digestion nitrogen: 50 μg N/L

– Reagent blank limited

Acknowledgements Acknowledgements Acknowledgements Acknowledgements

 TNI and NEMC

– Earl Hansen – Jerry Parr y

 USGS Office of Water and National Water Quality Laboratory (NWQL) for financial support and encouragement of numerous support and encouragement of numerous

• ngoing method development and laboratory

automation projects

– NWQL Nutrients Unit NWQL Nutrients Unit

 Speakers to follow for their time and effort to attend and contribute to this session

Tuesday, August 16 2011 NEMC, Bellevue, WA Challenges of Low-concentration Nutrient Analyses