Electrothermal MQ3824B/EX6 230V 50/60Hz, 1100W Macro-Kjeldahl Extraction Equipment

• Rugged, easy to clean stainless-steel construction
• Back-mounted brackets hold flask support rods (supplied with each unit)
• Choice of 2 or 6 positions
• Operates up to a maximum element temperature range of 550°C to 800°C
• Grounded stainless steel earth screen covering the heating element

The Electrothermal MQ Series of Macro-Kjeldahl Equipment has been designed for Kjeldahl extraction on a macro scale. These multibank units with either 2 or 6 recesses, have a stainless steel outer casing with back-mounted brackets (supplied with each unit), which can hold support rods of 12.7mm diameter max. There are 2 volume sizes available for both the 2 and 6 recess models, one for 100-300ml vessels and the second for 500- 800ml vessels.

Each heating mantle has its own energy regulator incorporating an On/Off switch and a “Mains to Heater” amber neon indicator. There is also a “Mains On” clear neon indicator on the front panel.

The lower part of the unit houses dedicated controllers for each recess. This “cool zone” housing is separated from the heating element by a stainless steel screen and a well-ventilated air space. The heating element consists of thermally insulated element wire stitched into a cartridge, and operates in the temperature range of 550°C to 800°C max.

All MQ Macro-Kjeldahl Equipment models (except MQ3868B/E) incorporate an earth screen to protect the user from electric shocks and are double-fused for extra safety. The rugged stainless steel outer casing is durable and easy to clean. The Macro-Kjeldahl Extraction equipment has been designed for Kjeldahl extraction on a macro scale to determine the protein content of food.

These multibank units with either 2 or 6 recesses, have a stainless steel outer casing with back-mounted brackets (supplied with each unit), which can hold support rods of 12.7mm diamter max. There are 2 volume sizes available for both the 2 and 6 recess models, one for 100 – 300ml vessels and the second for 500 – 800ml vessels.

Each heating mantle has its own energy regulator incorporating an On/Off switch and a “Mains to Heater” amber neon indicator. There is also a “Mains On” clear neon indicator on the front panel.

The lower part of the unit houses dedicated controllers for each recess. This “cool zone” housing is separated from the heating elements by a stainless steel screen and a well-ventilated air space. The heating element consists of thermally insulated element wire stitched into a cartridge, and operates up to a maximum element temperature range of 550°C to 800°C.

All MQ Macro-Kjeldahl Equipment models incorporate an earth screen to protect the user from electric shocks and are double-fused for extra safety (except for the MQ3868B/E which is only available as the 230V model as it is wired in directly). The rugged stainless steel outer casing is durable and easy to clean.

For food analysis

The Macro & Micro-Kjeldahl equipment consists of multimantles with 2 or 6 positions which heat to an ultra-high temperature. Both can be used for the Kjeldahl analysis to determine protein content in food.

The method consists of heating a substance with sulphuric acid, which decomposes the organic substance by oxidation to liberate the reduced nitrogen as ammonium sulphate. In this step potassium sulphate is added to increase the boiling point of the medium (from 169°C to 189°C). Chemical decomposition of the sample is complete when the medium has become clear and colourless (initially very dark).

The solution is then distilled with sodium hydroxide (added in small quantities) which converts the ammonium salt to ammonia. The amount of ammonia present (hence the amount of nitrogen present in the sample) is determined by back titration. The end of the condenser is dipped into a solution of boric acid. The ammonia reacts with the acid and the remainder of the acid is then titrated with a sodium carbonate solution with a methyl orange pH indicator.

• Degradation: Sample + H2 SO4 –> (NH4)2 SO4 + CO2 + SO2 + H2 O
• Liberation of ammonia: (NH4 ) 2 SO4 + 2NaOH –> Na2 SO4 + 2H2 O + 2NH3
• Capture of ammonia: B(OH)3 + H2O + NH3 –> NH4 + B(OH)4 –
• Back-titration: B(OH)3 + H2O + Na2 CO3 –> NaHCO3 + NaB(OH)4 + CO2 + H2 O

The Kjeldahl method’s universality, precision and reproducibility have made it the internationally-recognized method for estimating the protein content in foods and it is the accepted standard method.