Phthalate detection process
Sample preparation:
(1)
Soxhlet method
take
5 ~ 10g
Sample, broken to
3mm
×
3mm
, mixing, precision weighing
2.0000g
, placed in an extraction cylinder stacked with filter paper, the amount of addition: the extractor siphon once, then pour into the extractor two-thirds,
45
Soxhlet extraction in a water bath at °C
8
Hour, transfer the extract to an evaporating dish, drain in a water bath, and dilute the residue with methanol.
25.00ml
Shake well in a volumetric flask
0.45
μ
m
The organic filter is filtered and stored in a glass vial for testing.
Note: Change the solvent to methanol. If necessary, dissolve the extract in the evaporating dish with dichloromethane and then dilute to volume with methanol. The main purpose is to dissolve and transfer the extract from the evaporating dish to a volumetric flask.
(2)
Ultrasonic extraction method (for liquid samples)
take
5 ~ 10g
Sample, mix, precision weigh
2.0000g
Placed
50ml
In a flattened flask, add
25.00ml
Methanol
(
Pipette or pipette removal
)
, after sealing the lid, seal with a raw material tape (polytetrafluoroethylene film).
Ultrasonic room temperature for two hours, make up, use
0.45
μ
m
The organic filter is filtered and stored in a glass vial for testing.
(3) Microwave extraction
take
5 ~ 10g
Sample, broken to
3mm
×
3mm
, mixing, precision weighing
0.5000g
, placed in a microwave extraction tank, added
15ml
Ethyl acetate,
100
Microwave treatment
30min
, the power is
500w
Transfer to an evaporating dish and then dry it. The residue is made up with methanol.
25.00ml
Shake well in a volumetric flask
0.45
μ
m
The organic filter is filtered and stored in a glass vial for testing.
Note: For dirty samples, it needs to be cleaned, especially for leather samples, which need to be purified after microwave treatment.
Purification column: purification column is
Hahnschliff(
specification:
220*15mm)
,by
4g
Silicone and
1cm
Composition of sodium sulfate. Silicone is added before use
10%
Water inactivates it (put the silica gel in a beaker, add some water, then spin to evaporate at room temperature and atmospheric pressure)
1
In hours, the silica gel can be stored in a sealed glass bottle at room temperature.
Purification step
:
First with
15ml
Purify the column with n-hexane, discard the above column solution, pass the extract through the purification column, and control the flow rate to
0.5
drop
/S
Reuse
20ml
The extraction bottle is rinsed and the rinse is transferred to the purification column. Add in the eluent
50ml
(joined in two parts). Concentrate the collected solution to dryness and bring up to volume with methanol until
25ml
, filtered, to be tested.
Chromatographic conditions:
flow
move
Phase: Acetonitrile: Water
color
Spectrum
column:
AQ-C18
Detection wavelength
(UV)
:
224nm
column
temperature:
30
°C
flow
speed:
1.0 ml/min
Enter
kind
the amount:
10
μ
l
test:
Mobile phase preparation:
Take chromatographic pure acetonitrile and ultrapure water and use in solvent filter
0.45
μ
m
Organic membrane filtration, then ultrasound
10~20min
Degas and put in the solvent tray (
LC-CO310
Column thermostat).
Standard preparation
Accurately weigh standard materials
100mg
Left and right, dissolved in methanol and transferred to
100ml
In the volumetric flask, the volume is fixed to the tick line and is made into
1000ppm
Stock solution. Remove a certain amount of stock solution and place it
25ml
A volumetric flask is formulated into a standard solution of the desired concentration.
On the machine test:
(
1
) boot
a.
Turn on the power to the regulator and turn it on
LC-P310
Pump,
LC-UV310
UV detector,
LC-CO310
Column oven, to be detected by the detector self-test end wavelength display
254nm
When you turn on your computer, monitor, and printer.
b.
turn on
LC-P310
After the constant current pump, turn the vent valve counterclockwise (about
30
°), equipped with
30ml
Syringe draws out liquid
10
~
15ml
(or set the button on the pump interface to make it conditional to flush
Purge
State, let it rinse until the pump stops automatically)
, then return the venting valve to its original position;
c.
turn on
LC-WS310
LC workstation window.
(
2
Balance system
Set the required values ​​under the corresponding items of the workstation:
wavelength:
224nm
Column temperature:
30
°C
The flow rate is processed in the following different modes
Balance mode: every time
0.1ml/min
Increase the flow rate to
1.0ml/min
Flush the system with mobile phase to a smooth baseline (about
15min~30min
), and pay attention to observe whether the pipeline connection, column interface and pump head leak, such as leakage should be excluded.
(
3
Injection
a.
Wash the syringe with chromatographically pure methanol, then clean the syringe with the sample solution, and remove the bubbles.
10
μ
l
.
b.
Turn the injection valve handle to
Load
Position, insert the syringe needle completely into the inlet of the injection valve, and smoothly inject the sample solution. Unless otherwise specified, leave the syringe on the injection valve and quickly rotate the injection valve handle to
Inject
Location, the system will run automatically, collect data and record the map.
c.
Keep the injection valve handle in place
Inject
Location, about
1~2min
Switch back
Load
Position and pull the syringe out of the injection valve.
d.
After washing the syringe with methanol and then using the sample solution, continue the injection according to the above procedure until it is completed.
(
4
) data processing and printing
(
5
) cleaning system and shutdown
a.
After the data is collected, turn off the xenon lamp and continue to flush with the working mobile phase.
30min
.
b.
Cleaning the injection valve:
I
.
Suck with a starter syringe
10ml
Methanol
II
.
Put the needle into the mouth rinse head (
Rheodyne
Part Number
7125-054
) connect to the syringe outlet (do not needle) and connect them to the inlet;
III
.
Keep the injection valve in
Inject
At the position, the methanol is slowly pushed in, and the methanol is discharged through the sample overflow port through the injection needle introduction port, the guide tube, the injection needle introduction tube, and the injection needle seal ring.
c.
After the completion, slowly reduce the flow rate to
0
Turn off the workstation, turn off the pump, detector, and column oven in turn, and disconnect the power.
(
6
) Fill in the usage record.
Phthalates
6
Standard chromatogram 
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