A micromethod for the determination of iron and total iron-binding capacity in intraocular fluids and plasma using electrothermal atomic absorption spectroscopy.

A new micromethod (requiring only 30 microliters of sample) for the determination of iron (Fe) concentration and total iron-binding capacity (TIBC) in intraocular fluids (IOFs; aqueous and vitreous humors) and plasma has been developed using electrothermal atomic absorption spectrophotometry. Values for Fe concentration in the IOFs were similar between species and were generally higher in the vitreous (0.031-0.060 mg/liter) than aqueous (0.014-0.038 mg/liter) humors obtained from the same eye. Plasma Fe concentration and TIBC fell within established limits for all species studied. The iron binding capacity of the aqueous and vitreous humors from the same species is similar. While the TIBC of the aqueous humor is saturated to the same extent as plasma, vitreous TIBC is more highly saturated in all species. Using this method considerably less species variation in IOF Fe concentration was found as compared to previous studies. Some possible methodological reasons for this difference are discussed.