Microwave CalibrationMicrowave Calibration
Brenda R. ClevelandBrenda R. Cleveland
Plant/Waste/Solution/Media Plant/Waste/Solution/Media SectionSection
NCDA&CS Agronomic DivisionNCDA&CS Agronomic Division
June 21, 2011June 21, 2011 NCDA&CS Agronomic DivisionNCDA&CS Agronomic Division
Presentation TodayPresentation TodayMicrowave CalibrationMicrowave Calibration
ProcedureProcedure But first . . .But first . . .
June 21, 2011June 21, 2011 NCDA&CS Agronomic DivisionNCDA&CS Agronomic Division
PWSM SectionPWSM Section
Legislature enacted the service in Legislature enacted the service in 19741974
Analyze about 30,000 up to 35,000 Analyze about 30,000 up to 35,000 samples annuallysamples annually 18,000 waste18,000 waste 9-10,000 plant (this year >11,300)9-10,000 plant (this year >11,300) 2-3,000 solution and2-3,000 solution and 2-300 media2-300 media
June 21, 2011June 21, 2011 NCDA&CS Agronomic DivisionNCDA&CS Agronomic Division
PWSM SectionPWSM Section
Analyses (N, P, K, Ca, Mg, S, Fe, Mn, Zn, Analyses (N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, B, Na)Cu, B, Na)
FeesFees Routine $5Routine $5 Research $12Research $12 Out-of-State (2005) $25Out-of-State (2005) $25
Plus fees for additional testsPlus fees for additional tests NO3-N/NH4-N, heavy metals, CCE ($10 each)NO3-N/NH4-N, heavy metals, CCE ($10 each) Petiole NO3-N, Mo, Cl ($2 each)Petiole NO3-N, Mo, Cl ($2 each)
June 21, 2011June 21, 2011 NCDA&CS Agronomic DivisionNCDA&CS Agronomic Division
PWSM SectionPWSM Section
Six full-time laboratory staff plus 2-3 Six full-time laboratory staff plus 2-3 additional staff during busy seasonadditional staff during busy season Chemistry Lab Supervisor (Mark Chemistry Lab Supervisor (Mark
Buchanan)Buchanan) Chemist I (Jan Queen)Chemist I (Jan Queen) 3 Chemistry Technician III (Ying Kritalugs, 3 Chemistry Technician III (Ying Kritalugs,
Donta Baker and Kyle Crump)Donta Baker and Kyle Crump) 3 Research Technicians (Karla Barefoot, 3 Research Technicians (Karla Barefoot,
Ma Kpa, Brenda Woodall)Ma Kpa, Brenda Woodall)
June 21, 2011June 21, 2011 NCDA&CS Agronomic DivisionNCDA&CS Agronomic Division
PWSM SectionPWSM Section
One Agronomist (Dr. Michelle One Agronomist (Dr. Michelle McGinnis)McGinnis)
One Processing Assistant (Darlene One Processing Assistant (Darlene Carpenter)Carpenter)
One Section Chief (Brenda Cleveland)One Section Chief (Brenda Cleveland)
June 21, 2011June 21, 2011 NCDA&CS Agronomic DivisionNCDA&CS Agronomic Division
Microwave Procedure for ICP Microwave Procedure for ICP AnalysisAnalysis
Add 10 ml of nitric acid to each sample; Add 10 ml of nitric acid to each sample; 0.5 g plant/solid waste or 5 ml liquid waste0.5 g plant/solid waste or 5 ml liquid waste
Space samples evenly in microwaveSpace samples evenly in microwave Digest for 30 minutes at 210 wattsDigest for 30 minutes at 210 watts Flush sides of the flasks with hydrogen Flush sides of the flasks with hydrogen
peroxideperoxide Digest for 4 minutes more at 390 wattsDigest for 4 minutes more at 390 watts
Actual time varies depending upon the # of samplesActual time varies depending upon the # of samples
June 21, 2011June 21, 2011 NCDA&CS Agronomic DivisionNCDA&CS Agronomic Division
Quality ControlQuality Control
To verify that the samplesTo verify that the samples
have been cooked athave been cooked at
the correct power?the correct power?
(210 then 390 watts)(210 then 390 watts) calibratecalibrate adjustadjust
NIST sampleNIST sample
June 21, 2011June 21, 2011 NCDA&CS Agronomic DivisionNCDA&CS Agronomic Division
CalibrateCalibrate
Calibration is the process of Calibration is the process of adjustingadjusting the output or indication the output or indication on a measure-ment instrument to on a measure-ment instrument to agree with value of the applied agree with value of the applied standard, within a specified accuracystandard, within a specified accuracy
Assures that microwave power is Assures that microwave power is accurate and samples are digested accurate and samples are digested according to the SOP according to the SOP
June 21, 2011June 21, 2011 NCDA&CS Agronomic DivisionNCDA&CS Agronomic Division
CalibrationCalibration
Monthly calibration of all microwaves Monthly calibration of all microwaves Followed by analysis of a NIST Followed by analysis of a NIST
sample to verify that our procedure sample to verify that our procedure from start to finish from start to finish
June 21, 2011June 21, 2011 NCDA&CS Agronomic DivisionNCDA&CS Agronomic Division
Calibration - PreliminaryCalibration - Preliminary
Microwave is Microwave is warmed warmed Remove turntableRemove turntable Cook 1000 ml of Cook 1000 ml of
water in a beaker at water in a beaker at full power (100%) full power (100%) for 5 minutes for 5 minutes
Use room Use room temperature DI temperature DI waterwater
June 21, 2011June 21, 2011 NCDA&CS Agronomic DivisionNCDA&CS Agronomic Division
Calibration - SecondCalibration - Second
Watts determined Watts determined at four locationsat four locations front rightfront right front leftfront left back right andback right and back leftback left
June 21, 2011June 21, 2011 NCDA&CS Agronomic DivisionNCDA&CS Agronomic Division
Determine Power for 210 Determine Power for 210 WattsWatts
1.1. Measure Measure initial tempinitial temp of 1000 ml DI waterof 1000 ml DI water
2.2. Place beaker in the Place beaker in the front left section of front left section of cavitycavity
3.3. Cook 2 minutes at Cook 2 minutes at 210 watts210 watts
36% power36% power4.4. Remove and stir then Remove and stir then
measure measure final tempfinal temp5.5. Repeat steps 1-4:Repeat steps 1-4:
front right, left rear front right, left rear and right rearand right rear
June 21, 2011June 21, 2011 NCDA&CS Agronomic DivisionNCDA&CS Agronomic Division
Watts CalculationWatts Calculation
Calculate the watts Calculate the watts for each of these for each of these locations and runslocations and runs
T [final]-T [initial] * 35T [final]-T [initial] * 35 Calculate the average Calculate the average
If the average does If the average does ≠≠ 210 watts OR 210 watts OR
If the watts of any of If the watts of any of the locations is very the locations is very different from the different from the others others
Repeat the stepsRepeat the steps
June 21, 2011June 21, 2011 NCDA&CS Agronomic DivisionNCDA&CS Agronomic Division
Determine Power for 390 Determine Power for 390 WattsWatts
1.1. Same stepsSame steps 49% power49% power
2.2. And calculationsAnd calculations
June 21, 2011June 21, 2011 NCDA&CS Agronomic DivisionNCDA&CS Agronomic Division
Quality ControlQuality Control
To verify that the samplesTo verify that the samples
have been cooked athave been cooked at
the correct power?the correct power?
(210 then 390 watts)(210 then 390 watts) calibratecalibrate adjustadjust
NIST sampleNIST sample