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Partial molal volumes (V 0 φ ) and partial molal compressibilities (K 0 φ ) for glycine, L-alanine, L-valine and L-leucine in aqueous potassium fluoride solutions (0.1 to 0.5 mol·kg −1 ) have been measured at T = (303. 15, 308.15, 313.15 and 318.15) K from precise density and ultrasonic speed measurements. Using these data, Hepler coefficients (∂ 2 V 0 φ /∂T 2 ), transfer volumes ( V 0 φ ), transfer compressibilities ( K 0 φ ) and hydration number (n H ) have been calculated. Pair and triplet interaction coefficients have been obtained from the transfer parameters. The values of V 0 φ and K 0 φ vary linearly with increasing number of carbon atoms in the alkyl chain of the amino acids. The contributions of charged end groups (NH + 3 , COO − ), CH 2 group and other alkyl chains of the amino acids have also been estimated. The results are discussed in terms of the solute-cosolute interactions and the dehydration effect of potassium fluoride on the amino acids.

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