Rapid Quanti˜cation of Per˚uorinated Compounds in...
Transcript of Rapid Quanti˜cation of Per˚uorinated Compounds in...
499>80 499>99
2.18
313>119 313>269
363>169 363>319
413>169 413>369
463>219 463>419
513>269 513>469
299>80 299>99
399>80 399>99
Transitions
1.28
1.63
1.91
Retention Time
2.15
2.36
1.02
1.70
Structure
PFOA
PFNA
PFDA
L-PFBS
L-PFHxS
L-PFOS
Perfluoro-n-nonanoic acid
Perfluoro-n-decanoic acid
K Perfluoro-n-butanesulfonate
Na Perfluoro-n-hexanesulfonate
Na Perfluoro-n-octanesulfonate
Abbreviation
PFHxA
PFHpA
Name
Perfluoro-n-hexanoic acid
Perfluoro-n-heptanoic acid
Perfluoro-n-octanoic acid
Rapid Quanti�cation of Per�uorinated Compounds in Drinking and Surface Water Using LC-MS/MS Jeremy Post, Christopher Gilles, William LippsShimadzu Scienti�c Instruments, Columbia, MD
For Research Use Only. Not for use in diagnostic procedures.
Creating an environment suitable for measuring PFCs required several adjustments to the stan-dard LCMS work�ow in both the way samples were prepared and data was acquired. Iterative modi�cations started with tubing replacements and LC hardware recon�guration, which was fol-lowed by using glass and metal only for sample preparation. Even a seemingly minor adjust-ment such as inverting the autosampler vial septa proved important to reducing the PFC chemi-cal background. Following these modi�cations the background reduced signi�cantly making possible the acquisition of calibration curves measuring down to 2.5 fg on column. The low stan-dard %RSD value for PFOA was 4.1 and for PFOS, 5.6. Seven of the eight compounds were de-tected in surface waters across central Maryland whereas four were found in drinking water, though in reduced amounts relative to surface water.
Though nearly ubiquitous, per�uorinated compounds can be e�ectively and quickly measured directly from surface and drinking water using a modi�ed con�guration of the LCMS-8050. This method can be used for routine monitoring of PFCs in water samples requiring only minimal sample preparation.
Per�uorinated compounds (PFCs) are synthetic molecules with carbon chains to which �uorine is bound by high strength carbon-�uorine covalent bonds. Useful due to their surfactant and hydro-phobic physicochemical properties these materials are used broadly since the 1950s in industrial applications such as the conveyance of stain and stick resistance to a wide variety of materials and products including clothing, cookware, carpet, and food containers. These molecules, now classi-�ed as persistent organic pollutants, are highly stable and resistant to biological degredation, therefore they persist in the environment, bioaccumulate, and due to their ready transport by water are found even in remote regions of Earth. As contaminants of emerging concern, research on PFCs is ongoing to determine the impacts of these materials on human health and the envi-ronment. A CDC study detected four of these analytes in >98% of serum samples representative of the general US population above age twelve. Low level analysis of these compounds is chal-lenging due to their ubiquitous presence in the laboratory and analytical instrumentation com-ponents.
PFOS25 fg
Figure 3: PFC calibration curves demonstrating excellent linearity at low analyte concentration matched with spectra showing the analyte LOQ and a chromatogram with 60 fg on column .
Novel Aspect
Introduction
Method Results
Discussion
Conclusions
Fast, low chemical background, high sensitivity measurement of per�uorinated com-pounds in water.
Surface water samples were collected and stored according to document SOP #EH-01 Sur-face Water Collection using the Direct Method. As the mobile phase transfer lines, degasser membrane, pump inlet block, and sample vial septa all utilize PTFE, made from a prominent PFC, per�uorooctanoic acid (PFOA), these components were either exchanged or bypassed to eliminate all sources of extraneous analyte from the instrumentation. The calibration curve solutions were prepared in glass vials using glass syringes with a metal plunger. PFC standards were purchased from Wellington Laboratories. A Shimadzu LCMS-8050 was used for analyte separation and mass spectrometry. Analytes were ionized using negative mode electrospray ionization. All samples were passed through 0.2 um glass �ber �lter prior to analysis. The method required only 3.15 minutes. Table 1 provides optimized transitions and retention times for the PFCs measured in this method. Chromatography Parameters
Flow Rate: 0.35 mL/min Mobile Phase A: 10 mM ammonium acetate in waterColumn oven: 35°C Mobile Phase B: 10 mM ammonium acetate in 80:20 MeOH:ACNInjection volume: 20 μL Column: Supelco Titan C18 (50 x 2.1mm 1.9 um) Gradient: Linear 45% - 97% B 0-2.6 minutes
Mass Spectrometry Parameters
Nebulizing Gas 2.2 L/min Interface Temperature 230 CHeating Gas 8 L/min Desolvation Line Temperature 95 CDrying Gas 10 L/min Heat Block Temperature 225 C Column Oven 35 C
Liberty Reservoir
Centennial Lake
Little Patuxent River
Middle Patuxent River
Figure 1: Central Maryland surface water source locations
Figure 2: Direct method surface water sampling collection technique.
Table 1: Method information for the perfluorinated compounds measured in surface and drinkingwater
0.0 25.0 50.0 75.0 100.0 125.0 Conc.0
250000
500000
750000
1000000
1250000
Area
0.0 25.0 50.0 75.0 100.0 125.0 Conc.0
250000
500000
750000
1000000
1250000
1500000
Area
0.0 25.0 50.0 75.0 100.0 125.0 Conc.0
250000
500000
750000
1000000
1250000
1500000
Area
0.0 25.0 50.0 75.0 100.0 125.0 Conc.0
250000
500000
750000
1000000
1250000Area
0.0 25.0 50.0 75.0Conc.0
100000
200000
300000
400000
500000
600000
700000
Area
0.0 25.0 50.0 75.0 100.0 125.0 Conc.0
50000
100000
150000
200000
250000
300000
Area
0.0 25.0 50.0 75.0 100.0 125.0 Conc.0
25000
50000
75000
100000
125000
150000
175000
200000
225000
250000Area
0.0 25.0 50.0 75.0 100.0 125.0 Conc.0
25000
50000
75000
100000
125000
150000
175000
Area
PFNA5-3200 fg
PFOA25-3200 fg
PFHpA5-3200 fg
PFHxA2.5-3200 fg
PFDA25-1600 fg
L-PFBS2.5-3200 fg
L-PFHxS5-3200 fg
PFOS25-3200 fg
R2 = 0.999 R2 = 0.998 R2 = 0.998 R2 = 0.996
R2 = 0.997 R2 = 0.998 R2 = 0.999 R2 = 0.991
1.15 1.20 1.25 1.30 1.35 1.40
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
5500
6000313.00>119.10(-)313.00>268.90(-)
1.50 1.55 1.60 1.65 1.70 1.75
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
5500
363.00>169.10(-)363.00>319.10(-)
1.85 1.90 1.95 2.00 2.05
0
2500
5000
7500
10000
12500
15000
17500
20000
22500
25000
27500
30000
413.00>169.00(-)413.00>369.00(-)
2.10 2.15 2.20 2.25
0
2500
5000
7500
10000
12500
15000 463.00>219.00(-)463.00>419.00(-)
2.30 2.35 2.40 2.45 2.50 2.55
0
2500
5000
7500
10000
12500
15000
17500
20000
22500
25000
27500 513.00>269.00(-)513.00>469.00(-)
0.90 0.95 1.00 1.05 1.10
0
50
100
150
200
250
300
350298.90>98.90(-)298.90>79.80(-)
1.60 1.65 1.70 1.75 1.80
0
50
100
150
200
250
300
350
400
450
500
550
600
650
399.00>98.90(-)399.00>79.80(-)
2.10 2.15 2.20 2.25
0
250
500
750
1000
1250
1500
1750
2000
2250
2500
2750
3000
499.00>98.95(-)499.00>79.95(-)
PFNA5 fg
L-PFHxS5 fg
PFOA25 fg
PFHpA5 fg
L-PFBS2.5 fg
PFDA25 fg
PFHxA2.5 fg
0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 min
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
50000
PFHx
A
PFDA
PFHp
A
L-PF
BS
PFOA
L-PF
HxS
PFOS
PFNA
Per�uorinated compounds60 fg on column
0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 min
0
25000
50000
75000
100000
125000
150000
0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 min
0
10000
20000
30000
40000
50000
60000
70000
80000
90000
100000
110000
120000
0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 min
0
10000
20000
30000
40000
50000
60000
70000
0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 min
0
10000
20000
30000
40000
50000
60000
70000
80000
90000
100000
110000
120000
130000
140000
0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 min
0
25000
50000
75000
100000
125000
150000
175000
0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 min
0
25000
50000
75000
100000
125000
150000
175000
Lab Blank
Centennial Lake
Liberty Lake
Little Patuxent River
Middle Patuxent River
Drinking (Tap) Water
PFHxA 0.34 1.19 0.59 0.68 1.17 0.51PFHpA 0.1 0.36 0.33 0.33 0.33 0.16PFOA 0.79 1.09 0.92 1.04 1.05 0.37PFNA 0.22 0.24 0.24 0.25 0.26 0PFDA 0.71 0.43 0.16 0.07 0.08 0L-PFBS 0 0 0 0 0 0L-PFHxS 0 0 0 0.06 0.06 0.05PFOS 0 0 0.13 0.19 0.1 0
Middle Patuxent
River
Drinking Water
Lab BlankCentennial
LakeLiberty
Lake
Little Patuxent
River
Table 2 : Calculated amounts of PFC materials in the surface and drinking water samples. The measured amounts were averaged (n=4) and re-duced by the amount of each analyte detected in the Lab Blank (18MOhm purified water). These values were then divided by the injection volume to determine the final concentration in ng/L.
Figure 4: Representative PFC LC Chromatograms from 20uL injections of surface and drinking water.