Determination of Calcium, Magnesium, Copper, and Zinc in Red Blood Cells by Emission Spectrometry.

Abstract

b A method i s described for the determination of calcium, magnesium, zinc, and copper in red blood cells, the latter in a range of 0.1 to 3 pg. per gram.Blood collected carefully in plastic syringes fitted with stainless steel needles is centrifuged in the syringe to separate the blood cells.The red blood cells are ejected from the base of the syringe and ashed in platinum dishes at 450" C. The salts are converted to their chloride form and strontium i s added as the internal standard. The samples are applied to the surface of platform electrodes coated with plicene. The elements are determined by a direct reading emission spectrograph with a high voltage spark technique. The reproducibility o f the technique is of the order of 10%.Normal values for erythrocyte calcium, magnesium, zinc, and copper obtained with this technique are given and compared with values reported in the literature. HE GROWING INTEREST in the roleT of trace elements in metabolism and the production of disease requires methods for the measurement of metals at concentrations of a few parts per million that are both easy and precise. Emission spectrometry permits the simultaneous determination of many elements in tissues and the direct reading spectrograph shows promise of making this task less tedious and even more precise ( 7 ) . EXPERIMENTAL Instruments. A Jarrell Ash 3.4-meter Ebert mount spectrograph with direct reading attachment was used. Exit slits located on analytic lines for magnesium at 2852.1 A., copper a t 3247.5 A,, zinc at 3345.0 A., calcium at 4226.7 -4., and strontium at 4607.3 A,, were 86, 125, 88, 88, and 83.5 microns in width, respectively. Reagents and Chemicals.Ultrapure water was prepared from raw water by a system t h a t employed a still in combination with mixed-bed ion exchange resins ( 6 ) . The resistivity of the water was 10 X 106 ohms or greater. Hydrochloric acid was prepared from commercial anhydrous hydrogen chloride gas (81) and commercial sodium heparin was purified by extraction with dithizone (8). Spectrographically standardized pure salts obtained from Johnson and Matthey Co. Ltd., London, were used in the preparation of standard solutions.Cleaning of Apparatus. Glassware and polyethylene ware were cleaned in a dilute solution of detergent, placed in a 1 : 1 mixture of concentrated sulfuric acid and concentrated nitric acid for 8 to 12 hours and then rinsed thoroughly with ultra-pure water. Plastic syringes were dismantled, immersed for 24 hours in 1N sodium ethylene-diaminetetraacetate adjusted to p H 11 with sodium hydroxide and then rinsed thoroughly with ultra-pure water. Platinum crucibles were cleaned with sodium bisulfate and by immersion in boiling nitric acid (21).Preparation of Samples. With a 30-ml. plastic syringe (Stylex Syringe, J. F. Hartz Co., Toronto, Ont.) fitted with a stainless steel needle (Becton, Dickinson Co. Ltd., Toronto, Ont.) blood was taken from patients after an overnight fast. Purified heparin (0.1 mg.) was placed in each syringe before the blood was drawn to prevent coagul...

The calcium content of human erythrocytes

“…There was no correlation between the contents of magnesium and zinc. These values are slightly higher than those quoted by other workers (see Valberg, Holt & Szivek, 1964).…”

Spectrochemical Analysis of Sodium, Potassium, Calcium, Magnesium, Copper, and Zinc in Normal Human Erythrocytes*

“…The preparation of ultrapure water, purified heparin, and concentrated hydrochloric acid has been reported previously (28,29). Spectrographically standardized pure salts 1 were used in the preparation of standard solutions, and other chemicals were certified reagent grade.2 Trapped plasma measurements were made with RISA,3 which was stored in contact with Amberlite IRA 400 enclosed in a dialysis bag (30 …”

“…The procedure for cleaning glass and polyethylene ware, plastic syringes, and platinum crucibles has been described elsewhere (28). Stainless steel needles were cleaned in dilute detergent, rinsed with ultrapure water, placed in pyrex glass tubes, and sterilized by heat at 1030 C for 12 to 18 hours.…”

“…Analysis of erythrocyte calcium, magnesium, copper, and zinc. The preparation of samples and their analysis by emission spectrophotometry have been described elsewhere (28,35).…”

“…The concentration of calcium has been variously reported by different workers to range from 0 to as high as 18 Mug per g of cells (15,16,20,26,27). The purpose of this report is to describe a method employing an emission spectrophotometric technique (28) for the analysis of sodium, potassium, calcium, magnesium, copper, and zinc in erythrocytes, to present normal values in a group of 50 control subjects, and to compare the results with normal values in the literature. In addition a study has been made of the effect of sodium EDTA and washing procedures on the chemical composition of the erythrocyte, and two different methods of correcting for trapped intercellular plasma have been evaluated.…”