Presentation on theme: "An Introduction to Quality Assurance in Analytical Science"— Presentation transcript:
1 An Introduction to Quality Assurance in Analytical Science Dr Irene Mueller-HarveyMr Richard BakerMr Brian Woodget
2 Part 3 - Quality systems Contents: Introduction to quality systems (slides 3,4)QA and QC systems (slides 5-9)Measurement traceability (slides 10,11)Reference materials and check samples (slide 12)Keeping track of samples (slide 13)Quality manual (slides 14-17)Quality system filing (slide 18)The presentation contains some animation which will be activatedautomatically (no more than a 2 second delay), by mouse click or by useof the ‘page down’ key on your keyboard.
3 Without a Laboratory Quality System - too many mistakes can make analysis very costly; due tocosts of analysisexpenses caused by wrong decisions, orrepeating analysis of samplesinvestigation of problemsrevision of proceduresloss of good reputation
4 Prevention is Better than cure! ‘It costs less to prevent a problem than it does to correct it’A formal quality system in the laboratory should prevent mistakes by means of:quality assurance measuresquality control of the analytical resultsthorough documentation of the systemefficient maintenance of recordsregular audits of all aspects of the system
5 QA and QC systems Quality Control: Quality Assurance: planned activities designed to provide a quality product.Quality Assurance:planned activities designed to ensure that the quality control activities are being properlyimplemented.(As defined by the Association of Official Analytical Chemists)
6 QA SystemsQuality Assurance measures apply to the laboratory analytical work overall, which includes;identifying the person having the overallresponsibility for qualityhaving laboratory equipment calibratedto recognised standardsusing reference materialsjoining proficiency testing schemes withother laboratories doing similar tests
7 QC systems reagent blanks; verified standard solutions; blind samples Quality control measures apply to each analyticaltest in the laboratory byuse of:Control chartreagent blanks;verified standard solutions;check samples (from both within the lab and from outside);blind samplesreplicate analyses;and control charts
8 Quality systems - control charts A control chart is a means of ensuring that the method remains in ‘control’ - continues to perform in accordance with expectations. This usuallymeans that results from analysing standards fall within + 2 standard deviations of the accepted value (within the blue lines on the chart). Any results appearing outside the red lines (+ 3 standard deviations) indicate that the method is not longer in control and requires investigation.
9 Use of QC SamplesStep changeRegular analysis of a single control sample will identify a system in or out of control conditionsBiasTarget valueDriftIn controlDaily QC data
10 Measurement traceability In an absolute sense, the ‘true’ value can be defined only as being that value directly traceable to the base system of measurement (SI) or their derivatives - ie: to national or international standards via an unbroken chain of comparisonsSIunitTransfersaccuracyProvidestraceabilityCertifiedreference materialLaboratoryworking standardAnalytical method
11 Measurement traceability (2) The SampleAnalysed byThe SI units:Kg, Metre, MoleSecondary method:e.g. lab. methodCalibrated byPrimary methods(often gravimetric)e.g. AOAC, EPACalibration StandardsMethod routinelychecked byCertified byanalysisPrimary methods are often based on gravimetric procedures (e.g. AOAC, EPA methods)Secondary RMsIn-house QC materials(fairly cheap, larger amounts,matrix matched, short life)Certified Reference Materials(CRMs - expensive, smallamounts, best accuracy, long life)Periodicallychecked1
13 Keeping track of the samples Lab. No. F7-002Sample registration gives each sample a unique lab number.The sample register records all the information about the sample.Just like a sample’s passport, you should not confuse any sample with any other.The history of the sample should be traceable throughout.Sample integritySamples recorded on receipt1
14 Quality Manual A quality manual defines the quality system under Laboratory Quality SystemQuality ManualAdminPage 1 of 1Amiable LaboratoryIssue No.Issue DateTitle of SectionTitle PageIssued byQUALITY MANUALforAmiable LaboratoryBenevolent DepartmentWell-intentioned OrganisationUsual LocationA quality manualdefines the qualitysystem underwhich thelaboratory operatesThis Manual is issued under the authority ofIssue DateIssue No.3Copy No.A PersonHolderHead of LaboratoryQuality Manual - cover page