Quantification of Perfluorochemicals (PFCs) in Wastewater by LC-MS/MSYong QIU, (RCEQM, Kyoto Univ.) ○Shigeo FUJII (GS of Glob. Environ. Stud., Kyoto Univ.)
Shuhei TANAKA, Munehiro NOZOE (RCEQM, Kyoto Univ.)
LC-MS/MSによる廃水中のペルフルオロ化合物（PFCs）の定量, 邱勇・藤井滋穂・田中周平・野添宗裕
acid. Finally the cartridge was eluted by 2 mL methanol, fol-

1. INTRODUCTION
Perfluorochemicals (PFCs) have been being consumed for

lowed by 2 mL ammonium (1 wt%) in methanol / MTBE (1:9)

almost fifty years, but recently they are suspected to be persistent,solvent. The methanol portion in the elution was discarded andbioaccumulated and toxic chemicals.

the remaining was dried by nitrogen and further dissolved into

Contamination of somePFCs was reported in water environment and human blood in
1,2Japan , such as high perfluorooctanoic acid (PFOA) in Yodo
3River Basin .

50% acetonitrile.
In IPE method, about 2 g of condensed sludge was mixed with
1 mL of 0.5 N t-butyl ammonium hydrogen sulfate and 2 mL ofAnalysis of PFCs by LC-MS/MS was usually suffered from0.25 N Na2CO3 in a 15 mL disposable centrifuge tube to form ion

This study pro-pairs. Then 5 mL of MTBE was added, and the tube was placed

poses a proper pretreatment for aqueous phase and particulate phase

into a shaker at 150 rpm for 24 hours. After that, the mixed liquor

samples to reduce the matrix effect and to improve the analytical

was centrifuged at 3000 rpm for 30 min. The solid was rinsed byquality. Two different cartridges of Presep-C Agri (C18, 220 mg, 63 mL of MTBE two times, and all the supernatants were collectedmL) and weak anion exchange (WAX, 150 mg, 3 mL), were exam-

together and fixed to 12mL by MTBE. Then 3 mL of the super-ined for solid phase extraction (SPE) to concentrate and clean up

natant was dried by nitrogen and dissolved in 50% acetonitrile.

ionization suppression by matrix components.

PFCs in aqueous phase. Ion pair extraction (IPE), alkaline diges-

In AD method, about 2 g of condensed sludge was mixedtion (AD) and accelerated solvent extraction (ASE) were applied towith 10 mL of 0.05 M NaOH in pure methanol . After shaken at

extract PFCs from suspended solids. Then, distribution of PFCs in

150 rpm for 24 hours in a centrifuge tube, the digested liquor wassludge samples were determined by the optimized methods.

centrifuged and the supernatant was collected and diluted into
100mL by pure water. WAX-SPE process was applied to clean

2. MATERIALS AND METHODS-Twelve perfluorocaboxylic acids (PFCAs, F(CF2)x-1COO ) andup the supernatant.

three perfluoroalkyl sulfonates (PFASs, F(CF2)xSO3-) were obtained

In ASE method, solid sample was extracted by pure metha-from Wako Pure Chemical Industries, Ltd. and Tokyo Chemical

nol in ASE-200 (Dionex Company) at 100℃ and 2000 psi. TheIndustry Co. with purity of 95~98%. Wastewater and sludge sam-extraction was repeated three times to obtain about 50 mL crude

ples were periodically collected in a municipal wastewater treat-

extract. The extract was diluted into 500mL by pure water andment plant (WWTP) six times from August to December 2006.

WAX-SPE process was applied to clean up the matrix.

C18 and WAX cartridges were ordered from Waters Company.

LC (Ultra Microprotein Analyzer) coupled with tandem MS

Wastewater samples were firstly centrifuged and filtrated to(Finnigan Mat TSQ-7000) was applied to quantify PFCs in waste-

separate aqueous and particulate phases. SPE procedure by Pre-water samples. Agilent Zorbax XDB C-18 (150×2.1 mm, 5 μm)

3

sep-C Agri cartridge (C18-SPE) was same as a literature . The

coupled with XDB C-8 guard column (10×2.1 mm, 5 μm) werecartridge was conditioned by 10 mL methanol and 20 mL pure wa-used as stationary phase. Pure water with 10 mM ammonium

ter, and then loaded by 0.25~0.5 L of aqueous samples in an Elec-acetate (solvent A) and acetonitrile (solvent B) were used as mobile

tric Concentrator (Waters Company). After that, it was dehydrated

phase. Gradient flow was applied to accelerate LC separation.

by vacuum and eluted by 3 mL methanol. The elute was dried by

Solvent A:B changed from 50:50 at 1 min to 0:100 at 7 min, thengentle nitrogen gas flow and dissolved in 50 % acetonitrile solvent.

returned to 50:50 from 9.5 min to 10.5 min. Time interval of in-

SPE procedure by WAX cartridge (WAX-SPE) was modified

jections was set to be 18 minutes. m/z of daughter ion was M - 50from manufacturer’s guidelines. The cartridge was conditioned

for every PFCA -, and 80 (=SO3-) for every PFAS, where M was theby 2 mL methanol and 2 mL pure water, and then loaded bymolecular weight. Standard solution of 20ng/L was spiked into

0.1~0.25 L of samples which were acidified to pH3 by 10 wt%

each sample before extraction to estimate the process recovery (PR).

formic acid. After that, it was rinsed by 1 mL of 1 wt% formic

Relative standard deviation (RSD) of LC-MS/MS analysis wascalculated by six times injection of 100 μg/L multi component

tion of sludge in wet state was more preferable than in oven-dried

standard solution. Limit of detection (LOD) was assumed to bestate. Distribution coefficients of PFCs in sludge samples werethe minimum peak that can be automatically detected by software.

related with their carbon chain lengths.

Limit of quantification (LOQ) was assumed to be three times ofwere more easily adsorbed on particles and difficult to be ex-standard deviation As average for all PFCs, RSD was 13±6 %,tracted and analyzed.

LOD was 3±2 μg/L and LOQ was 16±5 μg/L.

2RESULTS AND DISCUSSION
Figure 1 shows the average value of PR for each PFC by

C18-SPE and WAX-SPE pretreatment methods. PR rates by bothmethods

were increased with carbon chain length forshort-chained PFCs (x=4~8) and decreased for long-chained PFCs
(x=9~18). This result might be explained by their hydrophobic

Process Recoverry

3.

Long-chained PFCsC18WAX1SD100%properties increased with carbon chain lengths. Because of the(8)
PFOS

(4)

(6)
PFHxS

PFBuS

PFODA (18)

PFTeDA(14)PFHxDA(16)PFDA

PFDoA (12)

(9)

(10)

PFNA

PFUnA (11)

(8)
PFOA

(6)

(4)

(6)

(8)

PFBuS

PFHxS

PFOS

PFOcDA(18)PFTeDA(14)PFHxDA(16)PFDoA (12)PFUnA (11)

(10)
PFDA

aqueous and particulate phase in activated sludge samples. Dw(9)Figure 2 shows distribution coefficients (Dw) of PFCs between

PFNAPFBA

sludge was helpful for solvent to extract PFCs (not shown here).

was increased by carbon chain length, indicating that long-chained

(7)

PFHxA

0(8)

than in oven-dried sludge (105oC), which implied that wet state of(7)

PFCs in condensed sludge (95% moisture) showed higher values

SD20

PFOA

mended for PFCs extraction in particulate samples. Analysis of

40

PFHpA

Because ASE was automatic and time saving, it was recom-Return sludge(6)compounds including proteins, which resulted in lower PR rates.

60(5)easily combined with proteins4. AD method can extract more143

ML in aeration tankPFPeA

lowed the sequence of IPE>ASE>AD. PFCs were reported to be80

PFHxA

PR values of particulate phase extractions for each PFC fol-(4)can reduce the matrix effect and improve analytical quality.

Fig. 1 Process recoveries of PFCs by C18 and WAX SPE (n = 55)
Distribution Coeffecient (Sludge/Water)

samples (DOC=26~60 mg/L), which suggested that WAX-SPE

PFHpA

tendency was more obvious in WWTP influent and primary effluent(4)general, WAX-SPE showed higher PR rates than C18-SPE. This(5)

sorbed by cartridge, but easy to be eluted from cartridges. InPFPeA

0PFBA

less hydrophobicity, short-chained PFCs were difficult to be ad-Fig. 2 Distribution coefficients of PFCs in activated sludge (n = 2)

PFCs were more easily attached on the particles because of theirstronger hydrophobicities. Mixed liquor (ML) and return sludge

ACKNOWLEDGEMENTS

had similar patterns on Dw values, but the values in return sludge

This research is partially supported by Grant-in-Aid for Scientifichave almost two times of those in ML, that corresponded to theResearch (No.17360257) and Mitsubishi Foundation 2005-2007.

concentration ratio of return sludge to ML

4.

CONCLUSIONSLC-MS/MS was successfully applied to measure 15 kinds ofPFCs in wastewater samples. Analytical quality was estimatedby process recoveries. C18 and WAX cartridge showed similar

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