CIH Analytical Chemistry
and Questions and
Answers Updated 2026
AccuracyB-
BAnswerBHowBwellByouBcomeBtoBhittingBtheBmark,Bi.e.,BhowBoftenByouBgetBtheBright
Banswer.BItBisBaffectedBbyBcontrollableBsourcesBofBerrorBandBincludeBmethodBerror,Bp
ersonalBerror,BandBinstrumentBerror.
AccuracyBErrorsB-
BAnswerBKnownBasBsystematicBerrorsBandBincludeBincorrectBcalculations,BpersonalBcar
elessness,BpoorlyBcalibratedBequipment,BandBuseBofBcontaminatedBreagents.BTheyBcon
tributeBtoBaBconsistentBbiasBtoBtheBresultsBthatBrendersBthemBinaccurate.
PrecisionB-
BAnswerBHowBcloselyBclumpedBtogetherByourBresultsBare,Bi.e.,BtheBabilityBtoBgetBthe
BsameBanswerBoverBandBoverBagain.BNotBasBimportantBasBaccuracy.
PrecisionBErrorsB-
BAnswerBAffectedBbyBindeterminateBorBrandomBerrors,BwhichBcannotBbeBcontrolled.BT
heseBincludeBintraBorBinterBdayBfluctuations,BsamplingBequipmentBvariationsBsuchBasB
randomBpumpBflowBfluctuations,BandBanalyticalBmethodBfluctuationsBsuchBasBvariation
BinBreagentBadditionBorBinstrumentBresponse.
PrecisionsBErrorsBContinuedB-
BAnswerBTheseBfactorsBcauseBvariabilityBamongBtheBsampleBresults.BStatisticalBtechniq
uesBareBusedBtoBaccountBforBrandomBerror.BForBexample,BincreasingBtheBnumberBofB
samplesBtakenBminimizesBtheBeffectBofBrandomBerror.
LabBBlanks/MediaBBlanksB-
BAnswerBSamplesBthatBhaveBnotBbeenBsentBtoBtheBfield.BUsedBforBqualityBcontrolBto
BdetermineBifBthereBisBcontaminationBatBfactoryBorBviaBtransport.BNIOSHBrecommend
sBanalyzingB6BmediaBblanksBfromBsameBsampleBlot.
, FieldBBlanksB-
BAnswerBSampleBmediaBtakenBtoBtheBfieldBbutBtheyBareBnotBexposed.BUsedBforBfield
BsamplingBqualityBcontrolBtoBdetermineBifBmediaBisBcontaminatedBonceBitsBleftBforBla
b.BNumberBofBrecommendedBfieldBblanksBisB2BperB10BsamplesBwithBaBmaxBofB10Bfi
eldBblanks.
BlindBSpikedBSamplesB-
BAnswerBSamplesBspikedBwithBaBknowBquantityBofBcontaminant.BLabeledBinBsameBma
nnerBasBfieldBsamples.BUsedBtoBverifyBlabBisBprovidingBaccurateBresults.BBeBcarefulBw
ithBthis.
CalibrationB-
BAnswerBLabBinstrumentsBmustBbeBcalibratedBfrequentlyBwithBconcentrationsBofBknow
Bsamples.BFieldBsamplingBpumpsBmustBbeBcalibratedBbeforeBandBafterBsampling.
PrimaryBStandardB(sampleBpump)B-BAnswerBdirectBmeasurementBofBvolumeB-
BpitotBtube,BbubbleBmeter,Bgilibrator,BinclinedBmanometer.
SecondaryBStandardB-
BAnswerBCalibrationBdeviceBcalibratedBagainstBprimaryBstandardB[rotameter]B-
BusedBtoBcheckBpumpBinBtheBfield
LimitBofBDetectionB-
BAnswerBLowestBconcentrationBdetectedBbyBtheBlaboratoryBinstrument.BUsuallyB3Btim
esBtheBinstrumentBnoiseBlevelB[S/N>3]
LimitBofBQuantificationB-
BAnswerBLowestBconcentrationBquantifiableBinBtheBlab.BUsuallyB10BtimesBtheBinstrum
entBnoiseBlevelB[S/N>10]B
LOD<=LOQ
and Questions and
Answers Updated 2026
AccuracyB-
BAnswerBHowBwellByouBcomeBtoBhittingBtheBmark,Bi.e.,BhowBoftenByouBgetBtheBright
Banswer.BItBisBaffectedBbyBcontrollableBsourcesBofBerrorBandBincludeBmethodBerror,Bp
ersonalBerror,BandBinstrumentBerror.
AccuracyBErrorsB-
BAnswerBKnownBasBsystematicBerrorsBandBincludeBincorrectBcalculations,BpersonalBcar
elessness,BpoorlyBcalibratedBequipment,BandBuseBofBcontaminatedBreagents.BTheyBcon
tributeBtoBaBconsistentBbiasBtoBtheBresultsBthatBrendersBthemBinaccurate.
PrecisionB-
BAnswerBHowBcloselyBclumpedBtogetherByourBresultsBare,Bi.e.,BtheBabilityBtoBgetBthe
BsameBanswerBoverBandBoverBagain.BNotBasBimportantBasBaccuracy.
PrecisionBErrorsB-
BAnswerBAffectedBbyBindeterminateBorBrandomBerrors,BwhichBcannotBbeBcontrolled.BT
heseBincludeBintraBorBinterBdayBfluctuations,BsamplingBequipmentBvariationsBsuchBasB
randomBpumpBflowBfluctuations,BandBanalyticalBmethodBfluctuationsBsuchBasBvariation
BinBreagentBadditionBorBinstrumentBresponse.
PrecisionsBErrorsBContinuedB-
BAnswerBTheseBfactorsBcauseBvariabilityBamongBtheBsampleBresults.BStatisticalBtechniq
uesBareBusedBtoBaccountBforBrandomBerror.BForBexample,BincreasingBtheBnumberBofB
samplesBtakenBminimizesBtheBeffectBofBrandomBerror.
LabBBlanks/MediaBBlanksB-
BAnswerBSamplesBthatBhaveBnotBbeenBsentBtoBtheBfield.BUsedBforBqualityBcontrolBto
BdetermineBifBthereBisBcontaminationBatBfactoryBorBviaBtransport.BNIOSHBrecommend
sBanalyzingB6BmediaBblanksBfromBsameBsampleBlot.
, FieldBBlanksB-
BAnswerBSampleBmediaBtakenBtoBtheBfieldBbutBtheyBareBnotBexposed.BUsedBforBfield
BsamplingBqualityBcontrolBtoBdetermineBifBmediaBisBcontaminatedBonceBitsBleftBforBla
b.BNumberBofBrecommendedBfieldBblanksBisB2BperB10BsamplesBwithBaBmaxBofB10Bfi
eldBblanks.
BlindBSpikedBSamplesB-
BAnswerBSamplesBspikedBwithBaBknowBquantityBofBcontaminant.BLabeledBinBsameBma
nnerBasBfieldBsamples.BUsedBtoBverifyBlabBisBprovidingBaccurateBresults.BBeBcarefulBw
ithBthis.
CalibrationB-
BAnswerBLabBinstrumentsBmustBbeBcalibratedBfrequentlyBwithBconcentrationsBofBknow
Bsamples.BFieldBsamplingBpumpsBmustBbeBcalibratedBbeforeBandBafterBsampling.
PrimaryBStandardB(sampleBpump)B-BAnswerBdirectBmeasurementBofBvolumeB-
BpitotBtube,BbubbleBmeter,Bgilibrator,BinclinedBmanometer.
SecondaryBStandardB-
BAnswerBCalibrationBdeviceBcalibratedBagainstBprimaryBstandardB[rotameter]B-
BusedBtoBcheckBpumpBinBtheBfield
LimitBofBDetectionB-
BAnswerBLowestBconcentrationBdetectedBbyBtheBlaboratoryBinstrument.BUsuallyB3Btim
esBtheBinstrumentBnoiseBlevelB[S/N>3]
LimitBofBQuantificationB-
BAnswerBLowestBconcentrationBquantifiableBinBtheBlab.BUsuallyB10BtimesBtheBinstrum
entBnoiseBlevelB[S/N>10]B
LOD<=LOQ
