Method 1668C Water

Polychlorinated Biphenyls (PCBs) in Water Samples


This method is used for the determination of polychlorinated biphenyls (PCBs) at low levels from water samples using isotope dilution HRMS (high resolution mass spectrometry).  All 209 individual PCBs are determined as well as the Totals for each congener group (e.g. Total Mono-PCB, Total Di-PCB).  Special interest is paid to the twelve PCBs designated by the World Health Organization (WHO) as the most toxic.  This subset of PCBs may also be called the co-planar or dioxin-like PCBs.  It is not currently possible to separate each of the 209 PCBs and some are reported as co-eluting compounds.

 

Samples are collected using grab sampling techniques.  If there is residual chlorine in the sample, add 80mg of sodium thiosulfate per L of sample and adjust the pH to 2-3 with sulfuric acid.  Use amber glass 1L bottles if possible for collection since the method requires the samples be protected from light.

 

Samples are typically extracted with methylene chloride.  The extraction procedure can vary based upon the amount of solids present in the sample.  If the sample contains <1% solids, then the sample can be extracted per normal procedures.  If there is >1% solids in the sample, then the method calls for the extraction of an equivalent of 10g of solids.  Keep in mind that this is a performance based method so lab procedures may vary.

 

The sample extracts undergo an extensive cleanup prior to analysis in order to remove interferences (dioxins, pesticides, PAH, etc.) in order to achieve the low limits of detection. 

 

NOTE:  This method is an update of and replaces Methods 1668, 1668A and 1668B.


(EPA 821/R-97-001)

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Method Data

Hold Times, Preservatives, Preps, Collection, Analytical & Documentation
Holding Time:   The method states that samples are good for up to one year if properly preserved, kept in the dark and at <6 °C.
Preservatives:   Keep samples in the dark. Adjust pH to 2-3 with sulfuric acid. If residual chlorine is present, add 80mg of sodium thiosulfate per L of sample.
Required Preps:   1L Amber glass bottle with Teflon-lined lid
Collection Method:   Grab sampling
Analytical Methodology:   HR GC/MS
Documentation:   1668C

Analyte List*

Analyte Formula CAS Number Detection Limit
2,3',4,4',5-Pentachlorobiphenyl (118)
C12H5Cl5
31508-00-6
20
 pg/L
3,3',4,4'-Tetrachlorobiphenyl (77)
C12H6Cl4
32598-13-3
20
 pg/L
2,3,3',4,4'-Pentachlorobiphenyl (105)
C12H5Cl5
32598-14-4
20
 pg/L
3,3',4,4',5,5'-Hexachlorobiphenyl (169)
C12H4Cl6
32774-16-6
20
 pg/L
2,3,3',4,4',5-Hexachlorobiphenyl (156)
C12H4Cl6
38380-08-4
20
 pg/L
2,3,3',4,4',5,5'-Heptachlorobiphenyl (189)
C12H3Cl7
39635-31-9
20
 pg/L
2,3',4,4',5,5'-Hexachlorobiphenyl (167)
C12H4Cl6
52663-72-6
20
 pg/L
3,3',4,4',5-Pentachlorobiphenyl (126)
C12H5Cl5
57465-28-8
20
 pg/L
2',3,4,4',5-Pentachlorobiphenyl (123)
C12H5Cl5
65510-44-3
20
 pg/L
2,3,3',4,4',5'-Hexachlorobiphenyl (157)
C12H4Cl6
69782-90-7
20
 pg/L
3,4,4',5-Tetrachlorobiphenyl (81)
C12H6Cl4
70362-50-4
20
 pg/L
2,3,4,4',5-Pentachlorobiphenyl (114)
C12H5Cl5
74472-37-0
20
 pg/L
Di-CB, Total
C12H8Cl2
DiPCB
 
Hepta-CB, Total
C12H7Cl3
HeptaPCB
 
Hexa-CB, Total
C12H6Cl4
HexaPCB
 
Mono-CB, Total
C12H9Cl1
MonoPCB
 
Nona-CB, Total
C12H1Cl9
NonaPCB
 
Octa-CB, Total
C12H2Cl8
OctaPCB
 
Penta-CB, Total
C12H5Cl5
PentaPCB
 
Tetra-CB, Total
C12H6Cl4
TetraPCB
 
Tri-CB, Total
C12H7Cl3
TriPCB
 

* The analytes and detection limits listed for each method represent the typical detection limits and analytes reported for that particular method. Keep in mind that analyte lists may vary from laboratory to laboratory. Detection limits may also vary from lab to lab and are dependent upon the sample size, matrix, and any interferences that may be present in the sample.