DeterminationofNa,Mg, P, K, Ca, Cr,Mn, Fe, Cu, Zn, Se, andMoby ICP-MS
G.
QUALITYCONTROL
1.
Prepareanew calibration curve for every set of samples analyzed, at least onceevery8hours. The correlation
coefficientmust be≥0.9995. If this criterion isnotmet, consult the supervisor.
2.
Analyze theBLANK, PB, solution immediately after the last calibration standard (Calstd) andbefore the first CCV.
It isused to checkbackground, carryover, or contaminationproblems. TheBLANK values forNa,Mg, P, K, Ca, Cr,
Mn, Fe, Cu, Zn, Se, andMomust be less thanhalf the concentrationof their corresponding lowest calibration
standard concentration. If theseBLANKvaluesareexceededby their correspondinganalytes, theerror action
“Fail”will beexecuted. If a “Fail”occurs, rinse for a fewminutes and tryagain. Any subsequent failuresmust be
rectifiedbeforeproceedingbecause theanalyte isnot blank subtracted from the samplesand theQLsand/or
accuracywill be compromised.
3.
The%RSDof replicate results forNa,Mg, P, K, Ca, Cr,Mn, Fe, Cu, Zn, Se, andMo concentrations ineach sample
and controlmust be5%orbetter for all elements, provided theyhaveanalytical solution concentrations above
the low standard (Crmaydemonstrate10%RSD in samples, but 5%RSD in control). If this criterion isnotmet,
re-prep the samples.
4.
A control sample (SRM1849a)must bepreparedand runwithevery “set”of samples. Likewise, if new reagent
lots areused, new control samplesmust beprepared. Record the concentrationsof analytes in the control
sampleona chart, according to the current laboratoryprocedure. The relative standarddeviation (%RSD) of the
to improve the laboratory’sprecision
by further trainingand/or instrumentmodifications, afterwhichanew control chartwill be started. If themean
recommendedproceduremust be followed forout-of-control analyses.
5.
The concentrationofNa,Mg, P, K, Ca, Cr,Mn, Fe, Cu, Zn, Se, andMo reported for the initial check standard
(CCV)must agree towithin4%of its nominal concentration. If this criterion is notmet, recalibratebefore the
controls areanalyzed. Analyzea check standardat least onceevery5 samples (10 tubes) andat thebeginning
andendof the sample set.Again, the concentrationofNa,Mg, P, K, Ca, Cr,Mn, Fe, Cu, Zn, Se, andMo
determined in the check standardmust not differ bymore than4% from its nominal value. If this condition isnot
met, recalibrateand rerunall samples thatwereanalyzedafter the last check standardwhich checkedback
properly. Consult the supervisor if driftingpersists.
6.
TheNa,Mg, P, K, Ca, Cr,Mn, Fe, Cu, Zn, Se, andMo concentration in the sample solutionsmayonlybe reported
if it is at or above the lower linearity limit (LLL -Na–0.25ug/mL;Mg–0.1ug/mL; P–0.25ug/mL; Ca, K–0.5
ug/mL; Cr,Mo–0.4ng/mL;Mn, Cu,-0.0025ug/mL; Zn–0.01ug/mL; Fe–0.025ug/mL; Se–0.2ng/mL. Report
to the supervisor anymeasuredanalyte concentrations in the samples that are less than the LLL (ng/mL and
ug/mL)×DF,whereDF is thedilution factor (samplevolume inmL/sampleweight ingrams). For liquids and
powders theDFvalues areapproximately50and250, respectively.
7.
Touse thedigital pipet for theadditionof internal standard solution, all criteria specified in local labSOPmust
bemet. Inparticular, thepipetmust be regularly calibrated to insure that it delivers avolumeof 0.5mLwith
accuracybetter than0.8%andprecisionbetter than0.2%RSD.
MTE-02
FORWORKINGGROUP/ERPUSEONLY
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