Laboratory requirements Dioxin Workshop, Leon Mexico

1
Laboratory requirements Dioxin Workshop, Leon
Mexico

• Richard Turle
• Analysis and Air Quality Division
• Environmental Science and Technology Centre
• Environment Canada

2
Principle of Methods

• Add surrogates (labeled internal standards)
• or spike a blank sample
• Extract according to matrix type
• Clean-up (very critical step)
• Fractionate (very critical step)
• Concentrate to known volume
• Analyze by GC-ECD for screening or GC-HRMS

3
Requirements for Dioxin Analysis

• Clean extraction lab
• HRGC-HRMS in EI mode
• Low Res NOT acceptable
• Labeled dioxin standards
• Highly trained staff
• A few CRMs available

4
Reasons for Using HRMS

• Sensitivity
• Modern HRMS can detect 0.01- 0.02 fg/ul TCDD
• Resolution
• _at_ 10000 resolution can separate masses to 4
  decimal places
• Necessary to eliminate co-eluting fragment ions
  from other compounds such as PCBs and chlorinated
  diphenyl ethers
• Eliminates the need for even more extreme cleanup
  procedures to remove matrix effects and
  interfering compounds

5
Canadian Reference Methods

• PP dioxin reg under CEPA
• Performance based
• First use of LOQ
• 2,3,7,8 TCCD regulated
• Other PCDD/FS requested

6
Internal QA Requirements for Dioxins in
Environmental samples

• Compares Hi-Res and Low Res
• Applicable to all matrices
• Used in monitoring

7
(No Transcript)
8
Cost of labs

• For dioxins, 500K for instrument, space needed
  for high-res GC-MS, clean extraction lab, wash-up
  lab etc cost 0.5 to 1M main cost due to
  HVAC needed.
• Also need UPS for continuous power supply

9
How do you know analyses are good?

• Use spiked samples to ensure repeatability
• Use CRMs to establish accuracy
• Proficiency testing ensures comparability with
  peers
• Exchange calibration solutions
• Accreditation ensures good procedures SOPS,
  quality system, management

10
Accreditation in Canada

• Required by Environment Canada policy
• ISO 17025
• CAEAL for environmental labs - Labs have
  published Scope of accreditation
• Labs must participate in PT if available

11
Quality Assurance Summary Method EPS RM/19 and
PM/23  
  1)     Before any sample is processed, all
pre-cleaned glassware are rinsed with solvents.
Contamination levels of individual
2,3,7,8-substituted congeners in glassware proof
rinses must not exceed the acceptable
limits. 2)     Before and sample is processed,
laboratory capability must be demonstrated by
conducting triplicate analyses of matrix blanks
spiked with natives and surrogates. Criteria for
accuracy and surrogate recoveries must be
met. 3)     Before extraction, each sample is
spiked with native congeners and
isotopically-labeled surrogates to assess the
degree and analyte loss during sample workup. If
the recovery of natives and surrogate is outside
the acceptable range, the sample must be
re-processed and re-analyzed. 4)     A method
blank consisting of blank media (e.g. water,
filter, solvents) spiked only with surrogates
should be processed along with each batch of test
samples.
12
Quality Assurance Summary Method EPS RM/19 and
PM/23

• 5)     Two labeled analogs must be added to each
  sample extract immediately before GC-MS analysis
  as recovery (internal) standards to calculate
  surrogate recoveries
• 6)  Verification of MS resolution at 10,000 or
  better is required
• 7) A Window Defining Mixture containing the first
  and last eluting isomer within each homologous
  group of PCDD/F must be used to correctly define
  retention time windows
• 8)  Acceptable chromatographic separation
  between 2,3,7,8-TCDD/TCDF and its closest
  neighbouring isomers must be confirmed.

13
Quality Assurance Summary Method EPS RM/19 and
PM/23

• 9) The established calibration must be verified
  daily by analyzing the calibration verification
  standard. The calculated concentration of
  analytes and surrogates must be within the
  acceptable limits.
• 10)Detection limits must be assessed by analyzing
  the lowest concentration standard solution.
• 11)  As a check on accuracy, reference material
  is periodically analyzed as a sample.
• 12) Sample results must be fully documented. All
  QA/QC documentation and raw GC-MS data, must be
  available for auditing

14
Window Number Compound Quantification 1st Ions 2nd Ion Type Control Limits for Isotope Ratio
1 TCDF 13C12-TCDF TCDD 13C12-TCDF H6CDPE PFK 303.9016 315.9419 319.8965 331.9368 375.8364 316.9824 305.8987 317.9389 321.8936 333.9339 M/M2 M/M2 M/M2 M/M2 M2 Lock 0.65 0.89 0.65 0.89 0.65 0.89 0.65 0.89
2 P5CDF 13C12-P5CDF P5CDD 13C12-P5CDD H7CDPE PFK 339.8597 351.9000 355.8546 367.8949 409.7974 366.9792 341.8567 353.8970 357.8516 369.8919 M2/M4 M2/M4 M2/M4 M2/M4 M2 Lock 1.32 1.78 1.32 1.78 1.32 1.78 1.32 1.78
3 H6CDF 13C12- H6CDF H6CDD 13C12- H6CDD O8CDPE PFK 373.8208 383.8639 389.8157 401.8559 445.7555 380.9760 375.8178 385.8610 391.8127 403.8529 M2/M4 M/M2 M2/M4 M2/M4 M4 Lock 1.05 - 1.43 0.43 - 0.59 1.05 - 1.43 1.05 - 1.43
4 H7CDF 13C12- H7CDF H7CDD 13C12- H7CDD N9CDPE PFK 407.7818 419.8220 423.7766 435.8169 479.7165 430.9728 409.7789 421.8191 425.7737 437.8140 M2/M4 M2/M4 M2/M4 M2/M4 M4 Lock 0.88 1.20 0.88 1.20 0.88 1.20 0.88 1.20
5 OCDF OCDD 13C12- OCDD D10CDPE PFK 441.7428 457.7378 469.7780 513.6775 454.9728 443.7398 459.7348 471.7750 M2/M4 M2/M4 M2/M4 M4 0.76 1.02 0.76 1.02 0.76 1.02 0.76 1.02
15
Limit (Level) of Quantitation

• Based on ACS definition of 1983
• ASTM D6259-98 defines procedure
• 3 SD of a blank is LOD (MDL)
• Reasonable certainty substance is present
• i.e statistically different from a blank
• 10SD of a blank is LOQ
• /-30 uncertainty at 99 CL
• 99 confidence substance is measurable
• De facto definition of virtual elimination

16
Sampling

• Standard trace organic sampling for OCs
• Keep equipment for PCBs in oil separate
• Special equipment/bottles needed for dioxins
  (must be proofed)
• Need special sampling procedures for dioxins from
  stacks

17
GOLDEN RULE

• The analysis is only as good as the sample
• One dirty sample can contaminate many clean
  samples
• Use standard operating procedures
• Stack sampling need special training