Page 15 - Shimadzu Journal vol.7 Issue1

Environmental Analysis

Table 2 Youden Pair Data for TOC as NPOC To validate Standard Methods 4500-N E, five different sources of
.BUSJY water were obtained and distributed to six analysts across four labs.
/VNCFS PG VTFBCMF WBMVFT The five sources were: wastewater effluent, wastewater influent, fresh
5SVF $PODFOUSBUJPO NH -
surface water, saline surface water and ground water. The nitrogen
.FBO 3FDPWFSZ NH -
concentration of the samples was distributed across the linear curve of
1FSDFOU 3FDPWFSZ
the proposed TN method. Four of the laboratories analyzed a known
0WFSBMM 4UBOEBSE %FWJBUJPO
reference material at 13.5 mg/L total nitrogen. The average bias was
0WFSBMM 3FMBUJWF 4UBOEBSE %FWJBUJPO
-3.0%. Inter-laboratory precision for each matrix is shown in Table 4.
4JOHMF 0QFSBUPS 4UBOEBSE %FWJBUJPO
4JOHMF 0QFSBUPS 3FMBUJWF 4UBOEBSE %FWJBUJPO
Table 4 Standard Methods Inter-laboratory Precision for Total Nitrogen
Table 3 Statistical Summary for non-Youden pair data as NPOC
.BUSJY "WFSBHF SFTVMU NH - / 34%
.BUSJY
(SPVOEXBUFS
/VNCFS PG
VTFBCMF WBMVFT 8BTUFXBUFS *OqVFOU
5SVF 8BTUFXBUFS &⒐VFOU
DPODFOUSBUJPO / " / " / "
NH - 4VSGBDF XBUFS TBMJOF
.FBO 3FDPWFSZ 4VSGBDF XBUFS GSFTI
NH -
3FDPWFSZ / " / " / "
0WFSBMM 4UBOEBSE Pesticides and PCBs by GCMSMS
%FWJBUJPO 4U
0WFSBMM 3FMBUJWF In the United States, laboratories are required to use 40 CFR Part 136
4UBOEBSE
%FWJBUJPO EPA approved methods for compliance under the Clean Water Act
4JOHMF 0QFSBUPS (CWA). Certain industry categories are required to monitor for
4UBOEBSE
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%FWJBUJPO 4P pesticides and PCBs. EPA Method 608.3 , specifies a gas
4JOHMF 0QFSBUPS chromatograph with a halogen specific detector (usually an electron
3FMBUJWF 4UBOEBSE capture detector) for pesticides. Method 625.1 , Base/Neutrals by gas
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%FWJBUJPO
chromatography mass spectrometry (GCMS), is also allowed; however,
Overall, the precision and bias of the method was as expected. The only in full scan or Selected Ion Monitoring (SIM) mode, which is not
low concentration of 0.5 mg/L in reagent water shows a high bias. sensitive enough to reach the low detection limits required for
Generally, single and multiple laboratory percent relative standard compliance with most NPDES permits. We are developing a new
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deviation (RSD) increases as concentration decreases.
method, using the Shimadzu GCMS-TQ8040 (Fig. 3), to measure the
Method 608 pesticides and PCBs, taking advantage of the increased
Total Nitrogen Methods at both ASTM and Standard Methods sensitivity of triple quadrupole mass spectrometry (MS/MS). This new
method, still under development, is ASTM Work Item WK54549 New
ASTM D8083-16 Standard Test Method for Total Nitrogen, and Total Test Method for Determination of Pesticides, PCBs, and Polychlorinated
Kjeldahl Nitrogen (TKN) by Calculation, in Water by High Temperature Biphenyl Congeners in Aqueous Solution by Tandem GCMSMS . The
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Catalytic Combustion and Chemiluminescence Detection was written method is summarized in Shimadzu Application News No. GCMS-1601
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by this author and is already published but not yet approved by the Determination of Organochlorine Pesticides and Polychlorinated
USEPA for wastewater reporting. Shimadzu undertook the necessary Biphenyls Using GC/MS/MS Operated in the MRM Mode .
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steps to create the method in an effort to provide EPA with at least
one method in the event EPA decides to propose Total Nitrogen as a In this application note, the Shimadzu Scientific Instruments (SSI)
new parameter at 40 CFR Part 136.3 Table 1b . We have written much Solution Center compared the performance of two instruments -
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about this method, available in the Shimadzu Scientific Instruments single quad and triple quad GCMS - for semi-volatiles analysis. Many
white paper, Introducing a new ASTM Method for the Determination of people had voiced concern with the triple quadrupole instrument not
Total Nitrogen, and TKN by Calculation in Water Samples . meeting the same performance as a single quadrupole; however, SSI
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demonstrated equal, if not better, performance with the triple quad
In addition, to provide EPA with another alternative method, as Part GCMS-TQ8040 than the single quad GCMS-QP2020 in semi-volatiles
coordinator and an editor of Standard Methods, the author analysis. One of the concerns is the DFTPP mass tuning requirement of
collaborated with Standard Methods for the Examination of Water most full scan EPA GCMS methods. DFTPP was originally proposed in
and Wastewater Part 4000 Inorganic Anions to create a new method, 1975 as a reference compound to verify the performance of a GCMS
Standard methods 4500-N E. This inter-laboratory validated method is system prior to running any laboratory samples. Since 1975, other
currently written but not yet published because, at the time of this compounds, such as DDT/Endrin and pentachlorophenol, have been
writing, it is still in the balloting stage. Both of these new methods added to the DFTPP standard mix to demonstrate passing DDT/Endrin
measure total nitrogen using TOC analyzers configured with a total breakdown and tailing. Fig. 3 shows passing DFTPP spectra on both
nitrogen module, such as the TOC-L with TNM shown in Fig. 2. instruments.

Fig. 2 TOC-L with TNM Fig. 3 DFTPP spectra on the GCMS-QP2020 and the GCMS-TQ8040

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