ISI 41-1e Determination of COD


1. Scope The method is applicable to starch milk and hydrolysates

 

 LT 12. Dec. 1966
Rev. LT 16. Dec. 1997
2. Principle Titration with NaOH to pH 8.3.

 
3. Apparatus 3.1 Burette
3.2 pH meter
3.3 Volumetric flask 50 ml

 
4. Reagents 4.1 Sodium hydroxide 0.1 N
4.2 Phenolphtalein: 1 g in 1 l ethanol 90%

 
5. Procedure Fill volumetric flask (3.3) with liquid sample. Transfer to 300 ml conical flask.

Titration 

 Add 1 ml (4.2) and titrate with (4.1) to faint persistent pink  or use pH meter to 8.3
V = ml (4.2). N = normality of (4.2)

 
6. Calculation Calculate acidity as normality N of sample by averaging results of two samples with one decimal.

N = N V / 50

 
7. Notes J. Assoc. Off. Anal. Chem. 66 (1983) no. 6, 1395-1399 recommend pH 6.0 as end point, but AOAC limits this method to HFCS

 
8. Reference AOAC Official Methods of Analysis (15th edition)

Comments

Post a Comment

Popular posts from this blog

ISI 26-5e Determination of pH in Starch and Syrup

Return 1. Scope The method is applicable to native and modified starch, glucose syrups and hydrolysates.   LT 1966 Rev. LT 13 Sep. 1999 2. Principle pH is measured electrometrically in the water phase of a starch slurry or direct in hydrolysates and syrups.   3. Apparatus 3.1 pH meter glass electrode and temperature correction  Properly calibrated 3.2 Laboratory scale   4. Procedure Ambient   temperature Commercial starch: Shake 5.0 g sample with 25.0 ml distilled carbon dioxide free water for 60 s. The starch is allowed to settle for 15 min. Measure pH of the
Read more

ISI 19-6e Determination of Viscosity of Starch by Brabender

Return 1. Scope The method is applicable to starch   LT 08.12.1966 Rev. LT 7. Feb. 2000. 2. Principle Viscosity of native and modified starch is measured during controlled heating and cooling   Dynamic viscosity 3. Apparatus 3.1 Brabender viscograph, 700 cmg cartridge. Bowl rotational speed: 75 rpm. Starting temperature: 45  o C. Subsequent rate of temperature increase and decrease: 1½  o C/min. Use standardisation kit for calibrating. Starting temperature = Start of test. 3.2 Beaker, 1000 ml 3.3 Laboratory scale   4. Procedure Weigh starch sample equivalent to x g dry subs
Read more

ISI 01-1e Determination of Dry Matter in Starch by Oven Drying at 130 oC

Return 1. Scope The method is applicable to starch in native or modified form. LT 15 Dec. 1964 Rev.: LT 21 Nov. 1997 2. Principle The sample is dried to constant weight. 3. Apparatus 3.2 Dish of aluminium or glass with tight-fitting lid 3.3 Electrically heated constant-temperature oven. 3.4 Desiccator with dry drying agent 4. Procedure An empty dish (3.2) is dried 1/2 hour in oven (3.3) at 130  o C. Cool dish in desiccator (3.4) to room temperature and weigh on balance (3.1) to the nearest 1 mg. Weight = w 0   Let cool 40 min Distribute 5 g of sample in a uniform layer in dish. Close lid and weigh to the nearest 1 mg. Weight = w 1 Place the open dish with sample in oven preheated to 130  o C. Dry 90 minutes after oven has once again reached 130  o C. Close lid and cool in desiccator for 30 to 45 minutes. Weigh immediately after rem
Read more