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Deviating Samples UKAS TPS 63 Tim Platt Technical Manager.

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Presentation on theme: "Deviating Samples UKAS TPS 63 Tim Platt Technical Manager."— Presentation transcript:

1 Deviating Samples UKAS TPS 63 Tim Platt Technical Manager

2 Introduction EA LC identified ISO/IEC REQUIREMENTS not being met Clause 5.8 and 5.10 Integrity of test samples maintained Results reported – Accurately – Clearly – Unambiguously – Objectively – Include comments on sample quality or adequacy that may have compromised the result

3 Terminology Deviating – an abnormality or departure from what is expected Deviating samples – Those not correctly cared for or sampled inappropriately.

4 Deviating Samples Exceeded their holding time Lack pertinent information – Date – Time – Location – Identity of sampler/contact Not retained at appropriate temperature

5 Deviating Samples Presented in inappropriate containers /packaging Inappropriate headspace Insufficient quantity Denatured through heat/ light/ humidity Suffered microbiologically

6 UKAS TPS Policies and procedures in place – Sample integrity maintained – Ensure results reported accurately – Include comments on quality /adequacy where this may have impacted on results

7 UKAS TPS Laboratory to define “deviating sample” – Holding time (stability) – Storage /transit conditions – Pertinent sample information (date/time/identity) – Use of appropriate containers – Use of preservatives – Sample type as defined in accreditation schedule

8 Holding times Parameter Sample Size (ml) Holding time (days)BS/ISO Holding time (days) USEPA Metals BOD25012 Total and free Cyanide Sulphide10077 PAHs pre 40 post extraction VOCs2x60114 pH506HoursImmediate

9 Sample Containers Waters – Volatiles,BTX, GRO – 60ml amber glass containers* – Other organics 1x 1 litre amber glass container* – Inorganics 1x1 litre plastic container – Sulphide, Phenols, Cyanide, Metals, individual plastic containers with preservative – * no headspace

10 Preservatives Analyte - Preservative Cyanide - Sodium hydroxide Phenol - Sodium hydroxide Metals - Nitric acid Mercury - Potassium dichromate BOD - Unpreserved, no headspace Sulphide - Zinc acetate

11 Temperature control Volatile and Organic samples or those affected by biological activity should be stored at 5°C Samples should be stored in the dark MCERTS for waters “the sample storage environment shall maintain a temperature of 5 ± 3°C” Cool transportation – cool boxes, ice packs, fill box, pre-chill, min/max thermometer.

12 UKAS TPS On identifying a deviating sample. – Consistent application/actions taken – Consult with customer and record – Initiate investigation into non- conforming work procedures if allowed to deviate in laboratory – Report results in appropriate manner.

13 UKAS TPS Laboratory required to demonstrate – Sample assessed upon receipt – If found to be deviating – contact customer for instructions – If customer requests to proceed, report will include a disclaimer indicating deviating sample and results may be invalid – If deviation occurred after receipt – investigation required

14 Deviating Samples UKAS TPS 63 Tim Platt Technical Manager


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