Operating instructions

10 METTLER TOLEDO DL36

The first titration

6. The first titration

To determine the moisture content of a sample accurately, parameters are stored in the

DL36 which you can change to match your sample. On delivery, the instrument has default

parameters stored which you can use to determine the moisture content in µg of many

organic substances, e.g. 99% ethanol.

The DL36 is switched on, the display shows <Run>.

– Press the Run key:

112 ✽ Pre-Titr

The pretitration starts; the solution is stirred and titrated until

it is free from moisture before you inject the sample.

An audio signal sounds, this means the solution is anhy-

drous (ready); however, the drift is not yet stable, its value is

≤500 µg/min. The drift is the amount of water titrated as

moisture per minute and recorded. For accurate determina-

tions, you should wait until

the drift is stable: it now changes by ≤0.1µg per minute.

– Prepare the sample: siphon off approx. 0.5 mL 99% etha-

nol (H

O content = 0.2%) with a syringe.

– Press the Run key:

– Enter the sample identification using the "minus", "period"

and numeric keys (max. 10 characters, see Section 8.3).

Confirm the entry with Enter:

"Start" and "Samp.In." (sample injection) appear alternately

in the display.

– Inject the sample and press the Run key:

The DL36 starts the titration and shows the constantly

changing drift and calculated amount of moisture.

When the titration is at an end, an audio signal sounds. The

drift and the result are displayed and the result printed out

on an attached printer.

5 Ready

2 Stable

ID ? ETHANOL

2 Start

Samp.In.

978 ✽ 467.2µg

3 786.6µg

• If you wish to determine the second sample immediately, prepare this and press the Run

key: the sample identification will be requested (see above).

• When you press the Enter key, "Stable" (or "Ready") is displayed: the moisture diffusing

into the cell will be continuously titrated, in other words the drift value is constantly

redetermined (so-called standby titration).

• When you press the Stop key, "<Run>" is displayed.