Common Problems of Automatic Digestion Instrument

Wiki Article

The automatic digestion instrument features advantages such as rapid digestion, high efficiency, energy conservation and ease of operation. Adopting a digital serial port design, it enables remote control. It has been successfully applied to sample pretreatment in industries including environmental protection, chemical engineering, food processing and biochemistry. Meanwhile, it can be used for the pretreatment and acid removal of microwave digestion, serving as an ideal supporting product for analytical instruments like atomic absorption spectrometers and atomic fluorescence spectrometers.

Environmental samples involved in microwave digestion include soil, solid waste, coal, coal fly ash, marine sediments, sludge and wastewater. Most environmental samples are products formed through complex reactions and deposition processes, with complicated matrix components containing both heavy metals and pesticide residues. Due to the diversity of environmental samples and the complexity of their matrices, it is necessary to consult a large number of literature references to determine sample properties and required digestion reagents, depending on the target analytes and testing methods.

Below are the common problems about the automatic digestion instrument:

1.What are the differences between this instrument, microwave digesters and aluminum digesters?

Microwave digestion is a sample digestion process conducted in a sealed environment under high pressure and high temperature conditions, featuring fast heating rate and short digestion time. This instrument performs sample digestion under high temperature conditions, with advantages of large sample throughput, wider temperature control range and high cost performance. Graphite has the characteristics of good thermal inertia, faster heating rate, small temperature difference between holes, strong corrosion resistance and longer service life. The main advantage of aluminum digesters is their relatively low price.

2.How long does it take to digest a batch of samples?

According to experimental standards, the color change of samples is generally used as the judgment criterion. Usually, the samples are digested for another 30–60 minutes after turning into a transparent blue-green color. The digestion time for regular samples is generally 2–3 hours.

3.How to treat the harmful gases generated during digestion?

The main harmful gas produced in the digestion process is sulfur dioxide, which is highly irritating and corrosive. Discharging it directly in the fume hood will corrode the fume hood and cause great harm to the laboratory environment. Currently, there are two solutions:

Equip a simple waste gas discharge device, and use the negative pressure suction of tap water to combine waste gas with tap water and discharge it into the sewer.

Use a waste gas absorption system: the waste gas goes through four processes including condensation, alkali neutralization, drying and filtration to effectively treat the waste gas generated during digestion.

4.What are the main factors affecting sample digestion?

Inaccurate temperature control, leading to incomplete sample digestion.

Large temperature difference between the instrument’s holes, resulting in poor parallelism of sample digestion.

Insufficient reagent dosage, causing incomplete sample digestion.

The article is sourced from China-Africa Trade Network