41
BÜCHI
Fat Determination
B-820/B-821
Press. system: air
p H2
55kPa
Air-pressure: 50kPa
p air
50kPa
Main menu
T oven
130°C
T inj.
220°C
Wait until ready
T FID
260°C
Req. flow H2+air
20 ml/2.5 s
Press. system: air
p H2
55kPa
Air-pressure: 50kPa
p air
50kPa
Main menu
T oven
130°C
T inj.
220°C
T FID
260°C
Req-flow H2+air:
20 ml/2.5 s
5. To check the
air flow rate
, the cursor is positioned on
<Press. system: Air> during which the air pressure is built
up. Wait until the actual pressure value is identical to the
set pressure value on display (Ready LED lights up).
6. Press the bulb to release a soap bubble. Use a stopwatch
to time how long the bubble takes from marker 1 to marker
3 (see figure 20).
When using the
short column
, the time should be 2.5 ±
0.1 sec (flow rate: 20 ml/2.5 ± 0.1 sec).
When using the
long column
, the time should be 2.7 ±
0.1 sec (flow rate: 20 ml/2.7 ± 0.1 sec).
7. If the stopped time deviates from the set time, the air
pressure value must be adjusted accordingly (position the
cursor on air pressure and enter new value). Once the
Ready LED lights up, the gas flow should be remeasured.
8. Dismantle the soap bubble meter from the FID.
Wear gloves or use a small towel for dismantling as the screw
is very hot.
Ensure that the soap bubble meter is removed from the FID
before returning to the main menu.
9. Position the cursor on <Main menu>.
While switching to the main menu the FID ignites automatically.
The oven temperature is set again according to the adjusted
mode.
Preheating
p H2
55kPa
Sample weight/Mode
p air
50kPa
Determination
T oven
130°C
Data manager
T inj.
220°C
Setup
T FID
260°C
5 Operation
Determination "Total Fat" (
short column
)
Press. system: air
p H2
280kPa
Air-pressure: 50kPa
p air
50kPa
Main menu
T oven
150°C
T inj.
220°C
Wait until ready
T FID
260°C
Req. flow H2+air:
20 ml/2.7 s
Determination "Fatty Acid" (
long column
)
