A new method for estimation of ethylene glycol in biological material

✍ Scribed by G. Rajagopal; S. Ramakrishnan

• Publisher: Elsevier Science
• Year: 1975
• Tongue: English
• Weight: 238 KB
• Volume: 65
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(75)90499-6

✦ Synopsis

Ethylene glycol is oxidised to formaldehyde by periodate. The formaldehyde is quantitatively converted into a purple coloured compound by chromotropic acid. The colour is measured in a spectrophotometer at 550 nm using standard ethylene glycol in the range of l-10 pg.

Chromotropic acid (4,5-dihydroxy-2,7-naphthalene-disulphonic acid) reacts quantitatively with formaldehyde around 100°C to give a purple coloured compound. This principle has been used in the estimation of serum triglycerides (1,2). While attempting a similar principle for estimating ethylene glycol (EG) in biological samples, a method has been successfully arrived at. Ethylene glycol is oxidised by sodium meta periodate to formaldehyde. After reducing the excess periodate by arsenite, chromotropic acid is added and the colour is developed in a boiling water bath in 30 min. The colour is measured at 550 nm.

Methods

Ethylene glycol in blood and tissues of rats, both normal and after acute intoxication were estimated by this method.

In principle, the method consists of the following steps. (1) Precipitation of proteins by trichloracetic acid (TCA). ( 2) Removal of interfering substances in the filtrate by treatment with copper sulphate-calcium hydroxide. (3) Oxidation of EG in an aliquot with periodate. (4) Reducing excess periodate by arsenite. (5) Colour development in an aliquot with chromotropic acid in a boiling water bath. Reagents 1. 10% TCA in water. 2. 20% copper sulphate. Dissolve 20 g CuSO,*SH,O in 100 ml water. 3. 25% calcium hydroxide suspension in water. 4. 0.025 M sodium meta periodate (NaIO,). Dissolve 0.503 g in 100 ml water. Stable at room temperature.