Jump to content Jump to navigation menu

Bromocresol green, 1 g

ACS
Pack Qty.
Pack.
3,3',5,5'-Tetrabrom-m-cresolsulfonphthalein, BCG
Empirical formula C21H14Br4O5S
Molar mass (M) 698,04 g/mol
Melting point (mp) 218 °C
WGK 1
CAS No. 76-60-8
EG-Nr. 200-972-8

Indicator pH 3.8-5.4
Dissolve 0.1 g in 100 ml ethanol (20 %) or 0.04 g in 0.58 ml NaOH 0.1 mol/l and fill up with water to 100 ml

€21.40/Pack Qty. 

excl. VAT. | 1 g per Pack Qty.

Art. No. T115.1

In stock
Delivery fast, simple and reliable!
from 6 Pack Qty. €20.33/Pack Qty.
from 24 Pack Qty. €19.26/Pack Qty.

Product details



Bromocresol green ACS

Technical Information
Colour conversion yellow - blue 
Transition range pH 3,8 - 5,4 
Bromocresol green
Selected quantity:   0
  1. Subtotal:  0.00
Art. No. Pack Qty. Pack. Price Quantity
T115.1 1 g glass

€21.40

T115.2 5 g glass

€37.10

T115.3 10 g glass

€63.35

T115.4 25 g glass

€119.35

In stock
Available
In procurement
No longer available
Delivery date currently unknown
Selected quantity:   0
  1. Subtotal:  0.00

Downloads / MSDS


General information

Further attractive products to complete your chromatography laboratory can be found on our Chromatography page!


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.


Thin Layer Chromatography (TLC)

Although the principle of thin-layer chromatography is more than a century old, it did not make its breakthrough as an analytical method until about 50 years ago.
Thanks to the development of new sorbents and supports, as well as increasing instrumentation and automation, TLC has become a versatile separation method. It is used both in qualitative analysis and in quantitative analysis.
Applications range from simple manual separation processes in classic TLC to automated processes in HPTLC (high performance thin layer chromatography).

Advantages of thin layer chromatography:

  • Higher sample throughput in less time
  • Suitable for screening tests
  • Pilot process for HPLC
  • The ready-to-use TLC layer functions as a data storage device for separation results
  • The separated substances can be used later for further analysis (e.g. IR, MS)
  • By switching the mobile and the stationary phases, the separation process can be optimised quickly and cost-efficient


Indicators and Dyes

Carl ROTH offers many indicators and dyes of high purity, which can be used in special applications.


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:

Guarantee analysis

Appearanceyellowish to pink-brown powder
Appearance of solutioncomplies
pH-transition range3.8 (yellow)-5.4 (blue)
Loss on drying (110 °C)≤3 %