HomeMy WebLinkAbout2019.01.30_CCO.p11_DeterminationofTable3PlusCompounds
Determination of Table 3 Plus Compounds by LC/MS/MS
Chemours Fluoroproducts Analytical Method
Revision date 1/10/2019
Instrument Setup
(Note: Trapping column installed on Line A. Delay column installed between mixer and
multisampler.)
Instrument: Agilent 1290 Infinity II LC with 6470 Triple Quad MS
Analytical Column: Agilent InfinityLab Poroshell 120 EC-C18
(2.1 x 50 mm, 2.7 µm); P/N: 699775-902
Guard Column: Agilent InfinityLab Poroshell 120 EC-C18
(2.1 x 5 mm, 2.7 µm); P/N: 821725-911
Trapping Column: Restek Ultra Aqueous C18 (4.6 x 50 mm, 5 µm); P/N: 9178555
Delay Column: Agilent Zorbax Eclipse Plus C18 (4.6 x 50 mm, 3.5 µm); P/N: 959943-902
Consumables
(Note: Avoid using glass. All standards, samples, and stock solutions should be prepped and stored
in HDPE or PP containers. Part numbers are provided below, but substitutions of similar products
can be made.)
LC vials: Microsolv, Cat. No. 9502S-PP-Clear
LC caps: VWR, P/N: 82028-424
Scintillation vials: VWR, P/N: 66021-692 (used for sample and standard dilutions)
HDPE bottles: Thermo Scientific, P/N: 2104-0004 (used for calibration stocks)
Luer-Lock syringes: Microsolv, P/N: 58903-S-K
0.2 um GHP filters: Pall Acrodisc, P/N: 4554
(or substitute with same dimensions and filter material)
Sample Preparation
All standards and stocks are prepared with a 50:50 methanol:water diluent. A 10-point calibration
curve is made from a 100 ppb mixed stock standard (containing the twenty-four Table 3 Plus
analytes) at the following dilutions: 0.01 ppb, 0.05 ppb, 0.1 ppb, 0.25 ppb, 0.5 ppb, 1 ppb, 5 ppb,
10 ppb, 25 ppb, and 50 ppb. Prepped standards should be filtered in the same way as the samples.
Note: The 100 ppb mixed stock standard is prepared in ultrapure water. The stock standard
should be stored in a refrigerator when not in use. After allowing the stock to warm to room
temperature, an aliquot is diluted 2x with methanol to produce a 50 ppb mixed standard in a
50:50 methanol:water matrix; this stock is then used for spiking and to prepare subsequent
dilutions for the calibration curve.
All samples are tested for pH when received to ensure that they are neutral (pH 6-8). If necessary,
dilute solutions of KOH or H2SO4 are used to adjust pH accordingly. Samples are prepared in
duplicate with duplicate spikes at different dilutions depending on the expected concentration
of the analytes. Each sample prep starts with a 2x dilution in methanol to produce a 50:50
methanol:water matrix. Subsequent dilutions are made with a 50:50 methanol:water mix. A 2x
dilution will be appropriate for most groundwater analyses (trace levels expected). If expected
concentration is unknown, err on side of caution and use large dilution factor initially. If not
detected, reprep with smaller dilution factor. Example preparations are listed below.
2x dilution and spike: 2.5 mL of sample is diluted with 2.5 mL of LC/MS grade methanol in a
scintillation vial, then vortexed and filtered with a 0.2 um GHP syringe filter. To prepare spikes,
2.5 mL of sample is diluted with 2.4 mL of LC/MS grade methanol and 100 µL of 100 ppb spike
solution in a scintillation vial, then vortexed and filtered with a 0.2 um GHP filter. Final expected
concentration of spike in vial is 2.0 ppb.
100x dilution and spike: 2.5 mL of sample is diluted with 2.5 mL of LC/MS grade methanol in a
scintillation vial, then vortexed to make a 2x prep. 100 µL of the 2x prep is diluted to 5.0 mL using
50:50 methanol:water, then vortexed and filtered with a 0.2 um GHP syringe filter. To prepare
spikes, 100 µL of the 2x prep is diluted with 4.8 mL of 50:50 methanol:water and 100 µL of 100
ppb spike solution in a scintillation vial, then vortexed and filtered with a 0.2 um GHP filter. Final
expected concentration of spike in vial is 2.0 ppb.
QC sample: A 5 ppb QC sample is prepared from a stock standard solution separate from the one
used for calibration following the same dilution and filtering protocol as for samples.
Analytical Method
LC Operating Conditions:
Mobile phase A: 2 mM Ammonium Acetate in 5:95 Acetonitrile:Water
Mobile phase B: Acetonitrile
Needle/seat wash: 50:50 Acetonitrile:Water, Multi-wash option using 2 cycles of seat
back flush and needle wash (10 seconds each)
Seal wash: 10:90 Isopropanol:Water
Injection volume: 5.00 µL
Flow rate: 0.500 mL/min
Maximum pressure: 600.00 bar
Solvent gradient:
End time: 9.50 mins
Column temp: 50.0°C
MS Operating Conditions:
Ion mode: ESI negative
Scan type: MRM
Gas temp: 150°C
Gas flow: 8 L/min
Nebulizer: 45 psi
Sheath gas heater: 200°C
Sheath gas flow: 8 L/min
Capillary: 3500 V
Nozzle voltage: 0 V
Time A B
Initial 0.00 min 85% 15%
1 1.00 min 85% 15%
2 5.00 min 10% 90%
3 6.40 min 10% 90%
4 6.50 min 85% 15%
QQQ Acquisition Parameters:
Compound Name MRM Transition RT (mins) Dwell
(msec)
Frag
(V)
CE
(V)
Cell
Accelerator
(V)
DFSA 175.0 -> 131.0 0.268 50 72 12 2
MMF 139.0 -> 95.0 0.271 50 93 8 1
MTP 175.0 -> 97.0 0.370 50 78 12 1
PPF acid 163.0 -> 118.9 0.394 50 58 8 5
PFMOAA 179.0 -> 84.9 0.437 50 54 12 1
R-EVE 405.0 -> 217.0 0.420 50 100 16 4
Byproduct 4 440.9 -> 241.0 0.509 50 114 28 1
Byproduct 5 439.0 -> 343.0 0.510 50 126 30 1
PMPA 229.0 -> 184.9 0.662 50 55 4 5
PFO2HxA 245.0 -> 85.0 1.046 50 60 8 1
NVHOS 297.0 -> 135.0 1.655 50 123 28 1
PEPA 279.0 -> 234.9 1.702 50 58 4 4
PFECA B 295.0 -> 201.0 3.027 50 55 8 3
PFO3OA 310.9 -> 85.0 3.298 50 54 12 3
PES 314.9 -> 135.0 3.388 50 109 20 5
HFPO-DA 329.0 -> 284.9 3.386 50 75 0 4
HFPO-DA_qualifier 329.0 -> 169.0 3.386 50 75 12 1
PFECA_G 378.9 -> 184.9 3.702 50 87 16 4
PFO4DA 376.9 -> 85.0 3.794 50 66 20 3
Hydro-EVE Acid 427.0 -> 282.9 3.825 50 90 12 3
EVE Acid 407.0 -> 262.9 3.825 50 78 8 2
Byproduct 6 397.0 -> 217.0 3.951 50 122 27 1
Byproduct 2 463.0 -> 262.9 4.072 50 160 32 1
Byproduct 1 443.0 -> 146.9 4.084 50 143 30 1
PFO5DoA 442.9 -> 85.0 4.085 50 66 8 1
Data Processing
Calibration: The full set of 10 calibration standards should be run at the beginning and end of a
sequence of samples. All 20 standard injections are used in constructing the calibration curve for
quantitation of unknowns. Continuing calibration checks should be performed after every 10
sample injections in the sequence using a mid-level standard; these are not included as points in
the calibration curve. The curve should be linear, not forced through the origin, and weighted
1/x. The acceptable accuracy range is 70%-130%.
Blanks: Three blanks should be run at the beginning of each sequence—a methanol blank taken
from the vessel used to perform 2x dilutions of aqueous stock standard and samples; a 50:50
methanol:water blank from the vessel used to perform subsequent dilutions; and an
environmental blank consisting of ultrapure water taken from the same type of container used
for sampling. Target analyte concentrations in all blanks must be less than one-half of the method
LOQ.
Method and/or solvent blanks are also used to monitor for carryover between samples,
particularly those with analyte levels detected at high concentrations. A typical sequence consists
of duplicate preps followed by their respective spikes, then a 50:50 methanol:water blank, and
repeating with subsequent sample prep/spike segments. Blanks in between sample segments
should be analyzed to quickly identify carryover contamination and are subject to the same
concentration criteria as described in the paragraph above.
Duplicates: Duplicate preps of the same sample must have a %RPD of ≤25% at mid- and high-
range concentrations and ≤50% at the minimum reporting limit (see equation below).
%RPD = (sample result - duplicate result) * 100
(sample result + duplicate result)/2
Results outside this range require a duplicate reprep. Both results should be reported, along with
the average.
Spikes: Acceptable spike recovery is in the range of 70%-130%. Spike recovery outside this range
does not necessitate reprep, but results should be flagged for further investigation due to
possible matrix effects.
QC Sample: A QC sample of known concentration should be prepped from a standard stock
solution separate from the one used for the calibration. Results must be within 70%-130% of the
true value.
Appendix A: Compound Details
Compound
Name
Molecular
Formula Structure CASRN
DFSA C2H2F2O5S
422-67-3
MMF C3H2F2O4
1514-85-8
MTP C4H4F4O3
93449-21-9
PPF Acid C3HF5O2
422-64-0
PFMOAA C3HF5O3
674-13-5
R-EVE C8H2F12O5
N/A
Byproduct 4 C7H2F12O6S
N/A
Byproduct 5 C7H3F11O7S
N/A
PMPA C4HF7O3
13140-29-9
PFO2HxA C4HF7O4
39492-88-1
NVHOS C4H2F8O4S
1132933-86-8
PEPA C5HF9O3
267239-61-2
PFECA B C5HF9O4
151772-58-6
PFO3OA C5HF9O5
39492-89-2
PES C4HF9O4S
113507-82-7
HFPO-DA C6HF11O3
13252-13-6
PFECA G C7HF13O3
801212-59-9
PFO4DA C6HF11O6
39492-90-5
Hydro-EVE
Acid C8H2F14O4
773804-62-9
EVE Acid C8HF13O4
69087-46-3
Byproduct 6 C6H2F12O4S
N/A
Byproduct 1 C7HF13O5S
29311-67-9
Byproduct 2 C7H2F14O5S
749836-20-2
PFO5DoA C7HF13O7
39492-91-6
Appendix B: Recommendations for Instrument Maintenance
Before starting a sequence, run an isopropanol blank and 3 method blanks (50:50
methanol:water) to flush the system and establish a “clean” baseline. At the end of a sequence,
run a “steam clean” line and end with an “idle” line (see screenshot below).
Both of these methods should be set up to utilize lines A2 and B2, which are 95:5 water:methanol
and 100% methanol, respectively. This will help to flush out any salts or other buildup that has
accumulated in the system. It is recommended to run the idle method while the system is not
actively being used.
After the idle method has completed and while the source temperatures are still low, open the
spray chamber and wipe down all surfaces – especially the spray shield and surrounding area –
with a 50:50 mixture of isopropanol and ultrapure water on a Kimwipe. This should be done daily
to prevent buildup.
A 50:50 acetonitrile:water mixture works well as a needle/seat rinse to minimize carryover. A
solution of 90:10 water:isopropanol should be used as the seal wash solvent, which should be
primed if bubbles are observed in the clear tubing between pump heads.
Solvent reservoirs should be periodically rinsed with isopropanol before rinsing and refilling with
the intended solvent. If possible, store solvents in amber bottles to inhibit microbial growth, and
prepare fresh solvents if not used within 1-2 weeks.