Buchi SpeedDigester K-436 Manual de usuario descargar pdf (Pagina 29)

6 Operation

29 K-425 / K-436 Operation Manual, Version A

6.2.2 Peroxide digestion —preparing sample tubes

During the preparation process, handling with peroxides and other dangerous substances is inevi-

table. Peroxides are strong oxidants and can form explosives! All steps must be performed under safe

laboratory conditions.

WARNING

Death or serious injuries by toxic and explosive peroxides.

Use only damage free sample tubes•

Exchange worn out or defective parts immediately•

Handle peroxides in a fume hood•

Do not bring peroxides into contact with highly combustible material•

Prerequisites

All sample tubes must be clean and free of damages.•

To achieve a reliable and reproducible digestion result the quality of sample material and the •

peroxide must be free of impurities and of adequate amount.

Filling of a sample tube

Take the sample tubes sequentially and weigh in sample material.•

Carefully(!)• add diluted sulfuric acid (e.g. 69%) of sufﬁcient amount to the samples.

Carefully(!)• add peroxide (e.g. H

30%) of sufﬁcient amount to the samples.

➡ The sample tubes can now be installed in a rack.

Note

Note down the sample weight and position to keep the probe processing and its analysis repro-•

ducible. All racks are marked on top with a "1" for the ﬁrst sample position.

The rack(s) can be used as a temporary storage for empty tubes during the preparation process.•

When adding the sulfuric acid and peroxide, rotate the tube to wash down any sticky sample •

material to the bottom and to coat the inside of the tube.

6.2.3 Installing a suction module and sample tubes (300 ml)

To withdraw hazardous fumes and vapors a suction module must be installed.

Prerequisites:

All hoses and connectors must be unclogged.

Installation steps:

For installation and handling all parts must be < 40 °C!

Install the plastic adapter piece to the suction module • 1.

Mount the hose connector at the EPDM hose • 2 of the suction module (i.e. Scrubber B-414 or

water jet pump).

The connector at the EPDM hose can be stored temporarily at the magnetic bracket at the rear •

side of the SpeedDigester.

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Buchi SpeedDigester K-436 Manual de usuario Pagina 29