3
Table 3. Comparison of recovery of phthalates from liquor without and with prior removal of ethanol before extraction.
Compound
CAS #
Abbreviation
With outethanol
removal
Recovery (%)
With ethanol
removal
Recovery (%)
Dimethyl phthalate
131-11-3
DMP
60.0
102.0
Diethyl phthalate
84-66-2
DEP
35.4
107.0
Diisobutylphthalate
84-69-5
DIBP
99.5
94.4
Di-n-butyl phthalate
84-74-2
DBP
106.0
104.0
Di-(4-methyl-2-pentyl) phthalate
146-50-9
DMPP
99.7
95.1
Di-(2-methoxy)-ethyl phthalate
117-82-8
DMEP
3.38
88.8
Diamylphthalate
131-18-0
DPP
109.0
108.0
Di-(2-ethoxy)-ethyl phthalate
605-54-9
DEEP
13.6
103.0
Dihexylphthalate
68515-50-4
DHP
104.0
101.0
Butylbenzyl phthalate
85-68-7
BBP
88.4
108.0
Di-(2-ethylhexyl) phthalate
117-81-7
DEHP
106.0
108.0
Di-(2-butoxy)-ethylphthalate
117-83-9
DBEP
83.1
104.0
Dicyclohexyl phthalate
84-61-7
DCHP
94.8
102.0
Di-n-octylphthalate
117-84-0
DNOP
103.0
106.0
Diphenyl phthalate
84-62-8
DPhP
77.1
112.0
Dinonylphthalate
84-76-4
DNP
110.0
109.0
The compound quantitation was performed by selecting
the most intense and unique ions of the compounds
providing selective mass chromatograms for individual
peak integration.
Finally, eight commercial liquor samples from a
local liquor shop were prepared by the described
sample preparation method for determining possible
contamination by phthalate esters.
Optimization of the liquor sample extraction
Chinese liquor typically contains 30 to 60 vol% ethanol.
Phthalate esters are highly soluble in ethanol, so the
extraction of phthalate esters using n-hexane as solvent is
less effective
2
. The removal of the major part of ethanol
from the liquor before n-hexane extractionis necessary to
avoid low recoveries.
Accurately measured 5.0 mL liquor samples were
transferred into glass tubes. Then the standard solution
was added to obtain a spiked solution at 0.80 mg/L
concentration level. Figure 1 shows chromatograms of
spiked sample and standard mixture runs. The experiment
results were compared with and without ethanol removal.
The results from the recovery experiment are shown in
Table 3. After removal of ethanol before the extraction
with n-hexane, good and consistent recoveries of the
phthalate compounds in the range of 89
-
112% were
obtained.
Results
In the following, the detection of five components of the
phthalate standard mixture is shown as an example of the
investigated PAE compounds listed in Table 3. Although
the full scan chromatograms shown in Figures 2-7 give
high background signals and include the elution of many
other compounds dissolved in the spirit, the selective
mass traces of the major phthalate ions allow a very good
selectivity for reliable peak area integration.
The mass spectra shown in Figure 8 are taken for
comparison to confirm the compound identity from the
analysis of the spiked sample and the standard run.
