Concentrations of calcium in mixtures of acid and alkaline detergents containing milk were determined by atomic absorption spectrophotometry. Four concentrations of milk (0.0, 0.01, 0.1, and 1.0%) were injected into flowing water containing four concentrations of acid or alkaline detergent (0.0, 0.03, 0.3, and 3.0%) at each of three temperatures (20, 45, or 70 C). The concentration of alkaline detergent was not a significant variable. Less calcium was detected in solutions of acid detergent at 20 C than in solutions at 45 or 70 C. An increase in concentration of milk from 0.01 to 0.1% resulted in an approximate 10-fold increase in the amount of calcium detected with both alkaline and acid detergents. When the concentration of milk was increased from 0.1 to 1.0%, the same 10 fold increase in the amount of calcium was noted for the acid detergent. However, 0.1 to 1.0% increase in the concentration of milk resulted in only a 7-fold increase in the amount of calcium detected in the alkaline detergent.

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Author notes

1Contribution from the University of Missouri Experiment Station, Journal Series No. 6808.

2Trade names and names of commercial companies are used in this publication solely to provide specific information. Mention of a trade name or manufacturer does not constitute a guarantee or warranty of the product by the U. S. Department of Agriculture or an endorsement by the Department over other products not mentioned.

3Agricutural Engineer, NCR, ARS, USDA.

4Department of Agricultural Engineering.

5Central Luzon State University.

6Department of Food Science and Nutrition.