Supplemental Data
1
2
3
Micro-scale quantitation of ten phthalate esters in water
4
samples and cosmetics by capillary liquid chromatography
5
coupled with ultraviolet detection: effective strategies to
6
reduce the production of organic waste
7
8
9
C.-H. Feng ()
10
E-mail address: [email protected]
11
Tel.: 886-7-312-1101 ext 2805, fax: 886-7-321-0683
12
Full postal address: 100, Shih-Chuan 1st Road, Kaohsiung, 80708, Taiwan.
13
14
15
Results and discussion
16
Optimization of the LLE procedure
17
Comparison of average recoveries of ten phthalate esters extracted with
18
ethyl acetate, toluene and n-hexane (100, 84 and 80 %, respectively)
19
showed that ethyl acetate was the best solvent for phthalate ester
20
extraction. For extracting the 10 phthalate esters, use of ethyl acetate in a
21
single extraction of 300 L, a double extraction of 150 L, and triple
22
extraction of 100 L revealed average extraction efficiencies (percentages)
23
of 71, 90 and 100%, respectively.
1
24
25
Optimization of UAE procedure
26
Comparison of extraction efficiency at 30, 40 and 50 ℃revealed average
27
recovery percentages of 100, 99 and 94, respectively. Thus, 30 ℃was the
28
optimal temperature for phthalate ester extraction. Because of the
29
semi-volatile properties of phthalate esters, temperature increases result
30
in loss of compounds. Comparison of extraction durations of 5, 10 and 15
31
min showed that 15 min was the best extraction duration for phthalate
32
ester extraction. Extraction of ethyl acetate was compared in a single
33
extraction of 300 L, a double extraction of 150 L, and a triple
34
extraction of 100 L. The comparison showed that a double extraction
35
using 150 L ethyl acetate obtained the best extraction efficiency.
36
37
Optimization of the MAE procedure
38
For the microwave parameter, comparisons of 200, 700 and 1000 W
39
treatments in terms of effects on extraction efficiency revealed that
40
average percentages of phthalate ester extraction were 89, 100 and 94%,
41
respectively. Therefore, 700 W was the optimal microwave treatment for
42
phthalate ester extraction. For the equilibration time parameter,
43
comparisons of 3, 6 and 9 min showed that 6 min was the best
44
equilibration time for phthalate ester extraction. In terms of extraction
45
repetitions, ethyl acetate extraction was tested in a 300 L single
46
extraction, a 150 L double extraction and a 100 L triple extraction.
47
48
Optimization of the DLLME procedure
2
49
Extraction efficiencies of chloroform solvent were compared in volumes
50
of 10, 15, 20, 30, 40 and 50 L. Theoretically, extraction solvent volume
51
should correlate with the sedimented phase obtained. As expected,
52
extraction solvent volume correlated with extraction efficiency in this
53
study. Comparisons of chloroform at volumes varying from 10 to 20 L
54
showed that 20 L obtained the best extraction efficiency. However, at
55
extraction volumes exceeding 20 L, excessive dilution negated increases
56
in extraction efficiency. Next, extraction efficiency was compared in
57
various dispersive solvents, including acetone, acetonitrile and methanol.
58
When used as dispersive solvents for phthalate ester extraction, the
59
average recovery percentages of acetone, acetonitrile and methanol were
60
93, 100 and 88, respectively. Thus, acetonitrile was the best dispersive
61
solvent for DLLME. To test the effects of dispersive solvent volume,
62
extraction efficiency of acetonitrile was compared in volumes of 30, 60,
63
90, 120, 150 and 180 L. At dispersive solvent volumes smaller than 90
64
L, collecting the sedimented phase was difficult because small droplet
65
formation was unobviously. At dispersive solvent volumes exceeding 90
66
L, however, the decreased distribution coefficient of phthalate esters
67
visibly partitioned the compounds into aqueous solution. Therefore,
68
acetonitrile 90 L was the optimal dispersive solvent volume in DLLME.
69
70
Optimized DLLME-SFO procedure
71
Comparison of varying volumes (5, 10, 15, 20, 25 and 30 L) of
72
1-dodecanol solvent in terms of phthalate ester extraction efficiency in
73
DLLME-SFO showed that 20 L was the optimal volume. Next,
3
74
comparison of methanol, acetonitrile, and acetone revealed phthalate ester
75
extraction efficiencies of 86, 89, and 100%, respectively. Thus, acetone
76
was the best dispersive solvent for DLLME-SFO. Extraction efficiency of
77
acetone solvent was then compared in volumes of 30, 60, 90, 120, 150
78
and 180 L . Notably, extraction recovery decreased as acetone volume
79
increased due to the effects of dilution. At dispersive solvent volumes
80
smaller than 30 L, obtaining the solidifying phase was difficult.
81
Therefore 30 L was the optimal solvent volume when using acetone as
82
dispersive solvent in DLLME-SFO.
83
84
Optimized CPE procedure
85
Three surfactants were evaluated: Triton X-100, Triton X-114 and
86
Genapol X-080. Since the structures of Triton X-100 and Triton X-114
87
contain chromophores, high concentrations of these surfactants in the
88
CPE interfere with I.S., DprP, BBP and DBP in the chromatograms. Since
89
the structure of Genapol X-080 does notcontain chromophores; Genapol
90
X-080 was a a suitable surfactant for CPE in this study. In terms of
91
physical-chemical properties, the critical mecellar concentration (CMC)
92
of Genapol X-080 is 0.028 % (w v-1), and its cloud point is 42 ℃. Tests
93
of the phthalate ester extraction efficiency of Genapol X-080 at
94
concentrations of 1, 2, 4, 8 and 12 % (w v-1) obtained average recovery
95
percentages of 86, 95, 100, 62 and 39%, respectively. As surfactant
96
concentration increased, the partitioning of phthalate esters into micelle
97
also increased until the volume of the redundant surfactant-rich phase was
98
too large to dilute the target analytes. Therefore, the optimal Genapol
4
99
X-080 concentration was only 4 % (w v-1) in CPE. In CPE, electrolyte
100
levels may enhance extraction efficiency by altering the density of the
101
aqueous solution as well as the cloud point temperature. In this study, use
102
of NaCl (0, 1, 2, 3 and 4 % (w v-1)) as electrolyte for extracting phthalate
103
esters achieved average recovery percentages of 100, 36, 74, 40 and 34 %,
104
respectively. Therefore, NaCl should be excluded when performing CPE.
105
In temperature testing, use of NaCl at temperatures of 60, 70, 80, 90 and
106
100 ℃ obtained average recovery percentages of 100, 88, 95, 89 and 93
107
%, respectively. Although NaCl was also tested at 50 ℃, phase separation
108
was incomplete, and collecting the surfactant-rich phase was difficult.
109
Therefore, 60 ℃ was the optimal temperature for CPE extraction of
110
phthalate ester. Extraction efficiency was then compared at equilibration
111
times of 30, 45, 60, 75, 90 and 120 min. At 45-90 min, the surfactant-rich
112
phase and the aqueous phase were completely separated, and extraction
113
efficiency exceeded 94%. Hence, 45 min equilibration time was selected
114
for phthalate ester extraction.
5
Table S1. Calibration curves for inter-day and intra-day analyses of the phthalate esters
Phthalate
esters
Linear range
(μg mL-1)
Inter-day
Intra-day
Linear equation (n=6)
r2
Linear equation (n=6)
r2
LOD
(μg mL-1)
DMP
0.5-50
y = 0.0411 x - 0.0036
0.999
y = 0.0395 x - 0.0127
0.999
0.05
DEP
0.5-50
y = 0.0319 x - 0.0150
0.998
y = 0.0308 x - 0.0203
0.997
0.02
DprP
0.5-50
y = 0.0243 x - 0.0035
0.999
y = 0.0241 x - 0.0103
0.998
0.10
BBP
0.5-50
y = 0.0230 x - 0.0129
0.998
y = 0.0236 x - 0.0190
0.997
0.10
DBP
0.5-50
y = 0.0249 x - 0.0096
0.998
y = 0.0248 x - 0.0133
0.998
0.05
DPP
0.5-50
y = 0.0187 x - 0.0086
0.998
y = 0.0192 x - 0.0141
0.998
0.06
DCHP
0.5-50
y = 0.0201 x - 0.0086
0.999
y = 0.0200 x - 0.0134
0.998
0.07
DnHP
0.5-50
y = 0.0180 x - 0.0046
0.998
y = 0.0186 x - 0.0085
0.998
0.07
DEHP
0.5-50
y = 0.0176 x - 0.0023
0.998
y = 0.0170 x - 0.0028
0.998
0.03
DOP
0.5-50
y = 0.0166 x - 0.0083
0.998
y = 0.0165 x - 0.0114
0.998
0.17
6
LLE
UAE
MAE
DLLME
DLLME-SFO
CPE
120.00
Recovery (%)
100.00
80.00
60.00
40.00
20.00
0.00
PAEs
Fig. S1.
The recovery of a water sample by using six different
techniques on the extraction of the phthalate esters (PAEs).
7
LLE
UAE
MAE
DLLME
DLLME-SFO
CPE
120.00
Recovery (%)
100.00
80.00
60.00
40.00
20.00
0.00
PAEs
Fig. S2.
The recovery of a toner sample by using six different techniques
on the extraction of the phthalate esters (PAEs).
8
LLE
UAE
DLLME-SFO
120.00
Recovery (%)
100.00
80.00
60.00
40.00
20.00
0.00
PAEs
Fig. S3.
The recovery of a emulsion sample by using three different
techniques on the extraction of the phthalate esters (PAEs).
9
Download

Supplemental Data Micro-scale quantitation of ten phthalate esters