Jump to content Jump to navigation menu

Kjeldahl tablets CT, 250 unit(s)

tablet 5,3 g
Examples of effect: Lead to damage to heath, cause irritation to eyes, skin or respiratory organs. Are fatal in larger quantities. Safety: As previously stated, in the event of skin irritation or contact with eyes, rinse with water or a suitable medium.
Examples of effect: Are harmful to aquatic organisms, toxic or highly toxic, acute or with long-term effects. Safety: To be disposed of as hazardous waste only, do not allow into the environment under any circumstances.
i causes serious eye irritation, very toxic to aquatic life with long lasting effects
P273 P280 P305+P351+P338
i avoid release to the environment, wear protective gloves/eye protection, IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing
Related products
Pack Qty.
Density (D) 2,7 g/cm³
UN-Nr. 3077

For determination of nitrogen.

€149.45/Pack Qty. 

excl. VAT. | 250 unit(s) per Pack Qty.

Art. No. 9637.1

In production
from 6 Pack Qty. €141.98/Pack Qty.
from 24 Pack Qty. €134.50/Pack Qty.
Carl Roth subscription service

Now recurring orders conveniently delivered as a subscription!

With the new Carl Roth Replenishment Service you can let products be ordered automatically which you need regularly in your lab!

How it works:

Put all products for your subscription in the desired quantity in the basket.


In the shopping cart, select the option "Order shopping cart as subscription" Order as subscription.


Set Starty point and interval for your subscription and submit order!

By the way: Through your account you can customize or delete your subscriptions anytime.

Kjeldahl tablets CT
Selected quantity:   0
  1. Subtotal:  0.00
Art. No. Pack Qty. Pack. Price Quantity
9637.1 250 unit(s) plastic


9637.2 1,000 unit(s) plastic


In stock
In procurement
Not available
Delivery date currently unknown
Selected quantity:   0
  1. Subtotal:  0.00

Downloads / MSDS

General information

Determination of Nitrogen according to Kjeldahl

The most common technique for measuring the amount of nitrogen in organic matter is the Kjeldahl method, which is used in a wide range of sectors such as environmental analysis, food analysis, water analysis and agricultural analysis, as well as in the pharmaceutical and chemical industries. In this traditional method, a precisely weighed sample is broken down using concentrated sulphuric acid, a process which digests its organic contents and reacts nitrogen to form ammonium sulphate.(CHNO)(s) → CO2 (g) + SO2 (g) + H2O (g) + NH4SO4 (solv, H2SO4)A catalyst or catalyst mixture consisting of copper, selenium, mercury and/or titanium is added to speed up the reaction. Sodium or potassium sulphate is used to give the sulphuric acid a higher boiling point. If the nitrogen is contained in a nitro, nitroso or azo compound, however, the mixture must be reduced with zinc before digestion takes place.
The nitrogen is now present in the sulphuric acid as ammonium sulphate. Adding a strong base (such as NaOH) neutralises the sulphuric acid and liberates ammonia from the solution.NH4SO4 (solv) + 2 NaOH (aq) → Na2SO4 (aq) + 2 NH3 (g) + 2 H2O (l) The ammonia is led into an acid (such as boric acid) by means of steam distillation.B(OH)3 (aq) + 2 H2O (l) + NH3 (g) → B(OH)4- (aq) + NH4+ (aq) The resulting strong base (borate ion) is back-titrated with a strong acid (hydrochloric acid or sulphuric acid). The excess weak boric acid is not captured in the process. A Tashiro's indicator that changes colour in the acid is used for titration. The amount of acid that has been used up can then be converted into the amount of nitrogen in the sample. NH4+ (aq) + B(OH)4- (aq) + HCl (l) → NH4Cl (aq) + B(OH)3 (aq) + H2O (l)To calculate the protein content of the sample, the varying nitrogen content of the amino acids must be checked and the relevant conversion factors applied. The nitrogen contained in food derives mainly from proteins, but different samples may also contain other sources of nitrogen.

Composition of the Kjeldahl tablets:

Typical composition
Art. No. Designation Weight of tablet (g) K2SO4 Na2SO4 CuSO4 CuSO4 • 5 H2O TiO2 Se Anti-foam
HN19 Kjeldahl tablets (mercury and selenium-free) 5 23,10 % 69,30 % 1,80 % - 2,80 % - -
HN20 Kjeldahl tablets (mercury and selenium-free) 2,5 23,10 % 69,30 % 1,80 % - 2,80 % - -
HN21 Kjeldahl tablets (Wieninger catalyst) 2,5 - 96,25 % 1,50 % - - 1,50 % -
HN22 Kjeldahl tablets (Missouri catalyst) 2,5 48,40 % 48,30 % 0,30 % - - - -
8225 Kjeldahl tablets, anti-foam 1 - 97,00 % - - - - 3,00 %
8236 Kjeldahl tablets CX 5,5 90,91% - - 9,09 % - - -
8241 Kjeldahl tablets C 5,1 98,04 % - - 1,96 % - - -
8243 Kjeldahl tablets CK 3,9 89,74 % - - 10,26 % - - -
9637 Kjeldahl tablets CT 5,3 94,34 % - - 2,83 % 2,83 % - -
9693 Kjeldahl tablets ST 3,5 99,90 % - - - - 0,10 % -
9763 Kjeldahl tablets TCT 3,71 94,34 % - - 2,83 % 2,83 % - -

Certificates of Analysis

You can search for and download your certificate of analysis for the selected product here. Please provide your batch number.
The following analysis certificates have been found:

Type analysis

Appearancelight blue tablets
Composition: K2SO4, CuSO4 · 5 H2O, TiO2.