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Ensuring High Level QA/QC Results in Analytical Chemistry. Development and improvement of analytical methods over 30 years Lian Liang, Cebam Analytical, Inc. The results speak for themselves. Comparing Cebam’s QA/QC Levels and Criteria of EPA 1631 and EPA 1630

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Ensuring high level qa qc results in analytical chemistry

Ensuring High Level QA/QC Results in Analytical Chemistry

Development and improvement of analytical methods over 30 years

Lian Liang, Cebam Analytical, Inc



Comparing Cebam’s QA/QC Levels and Criteria of EPA 1631 and EPA 1630

for Analyses of Total and Methyl Mercury

Precision (RPD, %)

Accuracy (Recovery, %)

* : Two samples per year

**: Long term lab comparison program, 6 samples per year, organized by Health Canada






Is it necessary to pursue QA/QC levels higher than EPA method criteria?

It definitely is to meet project needs!


Projects
Projects

Floodplain methylmercury biomagnification factor higher than that of the contiguous river (South River, Virginia USA)

Michael C. Newmana,*, Xiaoyu Xu a, Anne Condon b, Lian Liang c

(Environmental Pollution, 159 (2011) 2840e2844)

Summary of QC sample results generated by Cebam

Cebam has provided Analytical services to this site since 2007


Projects1
Projects

  • Project to evaluate mercury removal from contaminated soil

  • Analysis of methyl and total Hg in warm samples requested

worms

worms


Projects2
Projects

  • Cebam received 30+ samples transferred from another lab that had failed to produce results from the worm samples.

  • Despite there being very little sample left to analyze, Cebam scraped the remaining tissue off the walls and generated valuable results in limited time (48 hours TAT).

  • Helped the client to meet their deadline and get their Hg removal work approved.

  • If we had not improved the methods, we would not have been able to help the client.


How to approach h igh qa qc levels
How to Approach High QA/QC Levels

  • Complying QA/QC requirements from DOECAP auditors as a minimum

  • Improving available methods

  • Developing new techniques and methods


How time is divided at cebam analytical
How Time is Divided at Cebam Analytical

15 %

45 %

40%


Method improvement and development w ithout r esearch f unding support
Method Improvement and Development Without Research Funding Support

  • Both EPA and DOE have the Small Business Innovation Research (SBIR), but neither support development/improvement of analytical methods.

  • It is difficult for small commercial labs to compete with universities or institutes for research funding

  • In 1999, the American Water Association requested for proposals to develop a method for field isolation of As3+ in waters.

  • I submitted a proposal, and the proposal ranked the highest, but I did not receive the funding because the funding was intended to support universities.


What i have learned
What I Have Learned

  • Forget funding and be happy!

  • Conduct on-going research

  • Get returns from developed or improved methods.


Pay attention to individual projects, even individual samples, when deciding what to do and how to do it


Special handling of m icro s amples chiron larva
Special samples, when deciding what to do and how to do itHandling of Micro Samples (Chiron larva)


Chromatography peaks of mercury s peciation in a micro chiron larva s amples
Chromatography samples, when deciding what to do and how to do itPeaks of Mercury Speciation in a Micro Chiron Larva Samples


Homogenization of difficult samples by digesting whole samples
Homogenization of Difficult Samples by digesting whole samples

Whole fish

Crayfish

Feathers

Plant


Difficulties encountered in analyzing s amples from oak ridge site for total m ercury thg
Difficulties samples Encountered in Analyzing Samples from Oak Ridge Site for Total Mercury (THg)

THg concentration range:

Sub-ppt to ppm in a SDG,

→106 -fold difference


Effect of Carry-over Contamination from High Level Samples on the Results of Low Level Samples

*: Based on 1% memory

**: 1.3 ng/L is lowest water quality criterion for the Great Lakes System

(Table 4, 40 CFR 132.6);

***: 12 ng is the lowest nationwide criterion (40 CFR 131.36).


Solution
Solution on the Results of Low Level Samples

  • Perform pre-analysis to eliminate positive bias

  • Analyze samples within the optimum area (red) of the calibration curve of EPA 1631.


Difficulties in a nalyzing oak ridge site s amples for methylmercury mehg
Difficulties on the Results of Low Level Samplesin Analyzing Oak Ridge Site Samples for Methylmercury(MeHg)

  • Ratio of methyl Hg to inorganic Hg:

    (where x can be between 3-6 or even higher)

  • Ratio for water samples from other sites:

    10% to 50% (or even higher)

  • Using EPA 1630, high inorganic Hg may result in significant positive or negative bias on MeHg results.


Difficulties in analyzing oak ridge site samples for methylmercury mehg
Difficulties in Analyzing Oak Ridge Site Samples for on the Results of Low Level SamplesMethylmercury (MeHg)

  • This difference may greatly affect MeHg results because MeHg fractions are already very small fractions compared to inorganic Hg.

  • Solution: modifying EPA 1630 method to eliminate positive or negative interferences caused by high level inorganic Hg


Improvement related to epa method 1631 and epa 1630 1991 to 1994
Improvement on the Results of Low Level SamplesRelated to EPA Method 1631 and EPA 1630, 1991 to 1994

Liang L., Horvat M., and Bloom N.S., 1994, An improved speciation method for mercury

by GC/CVAFS after aqueous phase ethylation and room temperature precollection,

Talanta, 41,3,371.

Horvat M., Bloom N.S., and Liang L., 1993, A comparison of distillation with other

current isolation methods for determination of methyl mercury compounds in low

level environmental samples, Part 1: Sediment, Anal. Chim. Acta., 281, 135.

Horvat M., Liang L., and Bloom N.S., 1993, A comparison of distillation with other

current isolation methods for the determination of methyl mercury compounds in

low level environmental samples, part 2: Water, Anal. Chim. Acta. 282,153.

Liang L., and Bloom N.S., 1993, Determination of total mercury by single-stage gold

amalgamation with cold vapor atomic spectrometry, JAAS, 8,591

Liang L., Bloom N.S., and Horvat M., 1994, Simultaneous determination of mercury

speciation in biological materials by GC/CVAFS after Ethylation and room

temperature precollection, Clin. Chem., 40,4,602.

All published techniques are included in EPA 1631 and 1630.


Rewards f rom o n going research
Rewards on the Results of Low Level SamplesFrom On-going Research

Most of the method development and improvement has been presented at various ICMGP, and drawn great attention worldwide

For example, after the 4th ICMGP (1996), using developed methods for analysis of Hg in crude oils, Cebam has provided services to almost all oil companies in the world.



Oil refinery facilities

Oil refinery facilities 1992

Mercury in Crude Oil

  • Environmental impacts

  • Industrial issues

  • Damage refinery facilities due to Al + Hg → Al•Hg (amalgam)

  • Poisonous catalysts in refinery processes

  • Crude oil price is dependent on Hg concentrations


Status of oil hg in analytical c hemistry b efore 1993
Status of 1992 oil Hg in Analytical Chemistry Before 1993

  • Both Hg and the matrix are volatile, reactive, and complex.

  • Lack of reliable, sensitive analytical methods

  • Historically, the mercury content in crude oil was overestimated up to

  • 20 000 µg/kg


Crude oil hg related work
Crude Oil Hg Related Work 1992

  • Develop wet extraction method in 1993

  • Develop combustion based methods in 1995

  • Present combustion/wet extraction methods at 4th ICMGP in 1996

  • Applied combustion method for crude oil Hg projects of USEPA and Environment Canada, 2003-2005

  • Published 8 crude oil Hg relevant peer review articles, 1996-2007

  • Made important contribution to establishment of background level of crude oil Hg in the United States for the EPA

  •  Took the background level from 1000s µg/kgto 3.5 ±0.6 µg/kg


The combustion trap cvafs method for determination of crude o il hg
The Combustion/trap/CVAFS 1992 Method for Determination of Crude Oil Hg


Liz working on combustion
Liz 1992 Working on Combustion


Relying on basic chemistry is the key to the success
Relying 1992 on basic chemistry is the key to the success!


  • Cebam holds a long term project from NYDEC for analysis of biota samples for:

  • THg, MeHg, As, Se, Pb, Cd, and Ni

  • Because Cebam’s results are ranked No. 1 in the Inter-Lab comparison study.

  • Cebam relies on wet chemistry based methods for isolation and pre- concentration of trace metals prior to detection using instruments

  • Most other labs rely on ICPMS


Wet chemistry m ethods are reliable
Wet biota samples for:Chemistry Methods are Reliable

30 years ago, I worked as the head chemist for an environmental lab at CDC of Guangxi province in China.


  • When China first opened their doors to the world biota samples for:, the USEPA helped China to establish QA/QC for environmental monitoring.

  • Each province received 3American Standard Samples in 3 ampoules for three group analytes,

  • Trace Metals

  • Demand

  • Nutrients

  • All parameters in three USA PE samples were analyzed using wet chemistry methods.


Colorimetric method w ith or without spectrophotometer
Colorimetric biota samples for:Method With or Without Spectrophotometer.

Blank

1 ug/L

3 ug/L

5 ug/L

7 ug/L

9 ug/L

sample

Standard curve: blank, 1, 3, 5, 7, 9 µg/L of the analyte

Principle: Add a reagent to sample solution to form complex with a specific color.

Then determine the concentration by looking at which color is most similar with the sample, here it’s 3 µg/L 


Determination of arsenic based on hydride generation
Determination of Arsenic Based on Hydride Generation biota samples for:

Principle:

As5+ Sn2+ +I1-→ As3+

Sn2+ + HCl → H2↑

As3++ H2↑ → AsH3↑

AsH3↑ + HgBr2 → As2Hg3

(orange/brown mix color)

Sample

Standard curve:

HgBr2 Saturated paper

AsH3 generator

Samp.

Blank

1 ug

2 ug

3 ug

4 ug

5 ug


Sample volumes for analysis of metals by colorimetric method 1982
Sample Volumes for Analysis of Metals by biota samples for:Colorimetric Method, 1982

Total sample volume was 1000 mL sample from dilution of a USA PE sample. No sample available for QC (dup/spike).



Determination of gadolinium in biological materials using graphite furnace atomic absorption spectrometry with a tantalum boat after solvent extraction

Liang L., D'Haese P.C., Lamberts L.V., Van de Vyver F.L., and De Broe M.E.

Analytical Chemistry, 63,423, 1991

Lanthanoids

  • Gd-DOTA complex is used as a contrast agent for magnetic resonance imaging

  • It is used for tumor screening


Trace Metal Lab at Department of Nephrology-Hypertension, University of Antwerp, Antwerp, Belgium, 1991


Gd chemistry
Gd University of Antwerp, Antwerp, Belgium, 1991 Chemistry

  • Gadolinium is a rare-earth metal which easily forms carbonate with the carbon in graphite furnace

  • This results in difficulties in atomization using

  • GFAAS method.

  • Solution: make a boat using high temperature metal-Ta- and inserting it into the graphite furnace to prevent the sample solution from coming into contact with the furnace

  • This eliminates the formation of carbonate


Any questions
Any Questions? University of Antwerp, Antwerp, Belgium, 1991


Thank you
Thank You! University of Antwerp, Antwerp, Belgium, 1991


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