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c
Educating Consultants on
Laboratory Testing
Mike Cohen
Technical Development
Manager
DETS
Members Day
18th March 2015
Typical environmental lab
In reality
• Picture of laboratory
No only joking
The Laboratory Process
Sampling
Receiving samples
Registering samples
Preparing samples
Extracting samples
Chemical analys...
Sampling
• Taking a representative sample is usually outside
the control of the lab.
• What is important
– Using the corre...
Sample Containers
• These are supplied by the laboratory and are
dependant on the type of analysis required.
– Plastic tub...
Not a good idea
What could possibly go wrong?
• Its all down to communication
• Or lack of it
• You know what you want
• Labs think we kno...
On Receipt at the Lab
• Samples are checked against a chain of custody to
highlight any discrepancies, ambiguities, breaka...
Receiving samples
• Is there sufficient instruction with the samples
• Could the instructions be ambiguous
• Is there suff...
Registering samples at the lab
• Correct registration is very important since it determines
the analysis carried out and h...
Preparing samples
• Not all labs prepare samples the same way
– Some remove stones and analyse the remainder
– Some crush ...
Preparation of soils samples
• Depending on what analysis is asked for
• Analysis is typically carried out on an air dried...
Procedure for preparation of soil
samples
• Whole sample hand mixed and quartered, one
quarter for air dried analysis and ...
Extracting contaminants
• Labs tend not to analyse soil as such but extract
the contaminant of interest and analyse the
ex...
Chemical analysis - The Dark Art
Laboratory analysis
• Analysis tends to be split into 3 types
–Wet chemistry
– Organic
– Inorganic
Analytical Techniques
INORGANIC ORGANIC
SPECTROSCOPY
ATOMIC
ABSORPTION
ATOMIC
EMISSION
COLOURIMETRIC
SPECTROSCOPY
HPLC TLC...
Quality in the Laboratory
• ISO 17025
– MCERTS
– UKAS
– Proficiency Testing Schemes
• Quality Control
– Reference material...
When we say its 10mg/kg is it
• The answer is not really!
• All chemical analysis has a % uncertainty of
measurement which...
A few misconceptions
• The lower the limit of detection, the more
accurate the analysis
oNo the opposite is the case
• Res...
In conclusion
• Sampling is as important as analysis
• Differences in how a sample is prepared can
have a large influence ...
So what do consultants think of labs?
• Inflexible
– Labs try to be as flexible as possible but there are
limitations.
• W...
So what do labs think of consultants?
• Do labs think consultants expect too much?
I can assure you this is not what labs
think of consultants
Thank you
AGS Members' Day 2015 - Educating Consultants on Laboratory Testing Presentation
AGS Members' Day 2015 - Educating Consultants on Laboratory Testing Presentation
AGS Members' Day 2015 - Educating Consultants on Laboratory Testing Presentation
AGS Members' Day 2015 - Educating Consultants on Laboratory Testing Presentation
AGS Members' Day 2015 - Educating Consultants on Laboratory Testing Presentation
AGS Members' Day 2015 - Educating Consultants on Laboratory Testing Presentation
AGS Members' Day 2015 - Educating Consultants on Laboratory Testing Presentation
AGS Members' Day 2015 - Educating Consultants on Laboratory Testing Presentation
AGS Members' Day 2015 - Educating Consultants on Laboratory Testing Presentation
AGS Members' Day 2015 - Educating Consultants on Laboratory Testing Presentation
AGS Members' Day 2015 - Educating Consultants on Laboratory Testing Presentation
AGS Members' Day 2015 - Educating Consultants on Laboratory Testing Presentation
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AGS Members' Day 2015 - Educating Consultants on Laboratory Testing Presentation

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AGS Members' Day 2015
Educating Consultants on Laboratory Testing, Mike Cohen (DETS)

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AGS Members' Day 2015 - Educating Consultants on Laboratory Testing Presentation

  1. 1. c Educating Consultants on Laboratory Testing Mike Cohen Technical Development Manager DETS Members Day 18th March 2015
  2. 2. Typical environmental lab
  3. 3. In reality • Picture of laboratory
  4. 4. No only joking
  5. 5. The Laboratory Process Sampling Receiving samples Registering samples Preparing samples Extracting samples Chemical analysis
  6. 6. Sampling • Taking a representative sample is usually outside the control of the lab. • What is important – Using the correct container for the analysis – Filling them correctly – getting them to the lab in a timely fashion • If not the samples could be deviating and a comment would go on the report to state the integrity of the sample could be compromised
  7. 7. Sample Containers • These are supplied by the laboratory and are dependant on the type of analysis required. – Plastic tub for Inorganic contaminants – Glass jar for Organic contaminants – Small glass jar with no headspace for volatile contaminants
  8. 8. Not a good idea
  9. 9. What could possibly go wrong? • Its all down to communication • Or lack of it • You know what you want • Labs think we know what you want
  10. 10. On Receipt at the Lab • Samples are checked against a chain of custody to highlight any discrepancies, ambiguities, breakages or deviating samples. • Once this process has been completed and any issues resolved, then the samples are ready for registration onto The Laboratory Information Management System (LIMS)
  11. 11. Receiving samples • Is there sufficient instruction with the samples • Could the instructions be ambiguous • Is there sufficient detail Things we are asked • Can you tell me if this soil is contaminated? • Can you tell me what it is? • Can you tell me what’s in it? • Being non specific can cause problems!
  12. 12. Registering samples at the lab • Correct registration is very important since it determines the analysis carried out and how it gets reported – Have we got the correct det? – is total or dissolved det reqd – Have we chosen the det with the correct unit - %, mg/kg, µg/kg, g/l, mg/l, µg/l, ng/l – Have we chosen the correct Form of Expression – Ammoniacal nitrogen as N, as NH3, as NH4 – Have we included all the necessary information – sample dates, depths, BH numbers, sample descriptions, TRTs, dependant options, monohydric phenol or speciated. • If not you could end up with something you didn’t want
  13. 13. Preparing samples • Not all labs prepare samples the same way – Some remove stones and analyse the remainder – Some crush the whole sample and analyse it all • A new ‘Blue Book’ written by the SCA is being published by the EA which approves both methods. • IMPORTANT –you need to know which method your lab employs
  14. 14. Preparation of soils samples • Depending on what analysis is asked for • Analysis is typically carried out on an air dried (30°C) and ground sample where more representative sub sample can be taken. • However, some analyses, such as volatile organics are carried out on an as received (AR) sample. Volatile parameters would be lost if the sample was dried & ground. This results in it being more difficult to take a representative sub sample.
  15. 15. Procedure for preparation of soil samples • Whole sample hand mixed and quartered, one quarter for air dried analysis and one for as received • Air dried portion • Dried at 30°C and moisture content recorded • Stone content (>10mm) not recorded unless specifically requested • Whole dried sub-sample crushed to pass through a 450micron sieve • As received wet portion • Representative sub-samples are taken for each analysis
  16. 16. Extracting contaminants • Labs tend not to analyse soil as such but extract the contaminant of interest and analyse the extract. • Inorganic contaminants are digested in polar solvents such as acids, whereas organic contaminants are extracted into organic solvents
  17. 17. Chemical analysis - The Dark Art
  18. 18. Laboratory analysis • Analysis tends to be split into 3 types –Wet chemistry – Organic – Inorganic
  19. 19. Analytical Techniques INORGANIC ORGANIC SPECTROSCOPY ATOMIC ABSORPTION ATOMIC EMISSION COLOURIMETRIC SPECTROSCOPY HPLC TLC GC GC/MS Flame - Heavy metals Furnace - Low level heavy metals Hydride - As, Se, Sb Cold Vapour - Hg Simultane ous ICP ICP - MSOES Sequential ICP Heavy metals & rare earths ICP + USN - Low level heavy metals Flame Photometry -Na, K & Li } ION CHROMATOGR APHY (Conductivity detector) ECD, UV, Fluoresce nce FI D EC D VOC s SVO Cs Phenols PAHs Elemental Sulphur Explosives Pesticides ANIONS -CN -SCN -SO -NH - Cl,S,F,N O2 Class separati on PAHs Pesticid es PCBs Chlorina ted Species TPH (EPH+G RO) Solvents BTEX CHROMATOGRAPHY
  20. 20. Quality in the Laboratory • ISO 17025 – MCERTS – UKAS – Proficiency Testing Schemes • Quality Control – Reference materials – Duplicates – Blanks
  21. 21. When we say its 10mg/kg is it • The answer is not really! • All chemical analysis has a % uncertainty of measurement which depends on the analyte and the method employed. • Typically it can range from 10% to 30% (uncertainty in sampling is usually far greater) • What this means is that the result reported is within a range.
  22. 22. A few misconceptions • The lower the limit of detection, the more accurate the analysis oNo the opposite is the case • Results from different labs should always give the same results oNo it depends on the methods used • Total results mean total oFor organics, total means the total of the compounds analysed
  23. 23. In conclusion • Sampling is as important as analysis • Differences in how a sample is prepared can have a large influence on the final analytical result • The more information accompanying a sample, the quicker the analysis becomes.
  24. 24. So what do consultants think of labs? • Inflexible – Labs try to be as flexible as possible but there are limitations. • We cannot do a five day test in 3 days (no matter how much money is offered) • If you only have 1g of sample then we cannot do a full suite of analysis (we are not CSI) • Despite appearances we are human and occasionally we do make mistakes!
  25. 25. So what do labs think of consultants? • Do labs think consultants expect too much?
  26. 26. I can assure you this is not what labs think of consultants
  27. 27. Thank you

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