Tris/Tris·HCl: A Standard Buffer for Use in the Physiologic pH Range

Abstract

A buffer solution containing tris(hydroxymethyl)-aminomethane (0.01667 mol/kg) and its hydrochloride salt (0.0500 mol/kg) is proposed as a pH standard for the physiologically important pH range of 7.3 to 7.5. Standard pH values were assigned to this reference solution at temperatures from 0° to 50°C by means of measurements with hydrogen/silver chloride cells without transference. At 37°C, the assigned pH of this buffer solution is 7.382, with a temperature coefficient of -0.026 pH unit per degree Celsius. This new standard is more compatible with biologic fluids than is the previously certified phosphate buffer.

Triose phosphate isomerase from the blood fluke Schistosoma mansoni: Biochemical characterisation of a potential drug and vaccine target

“…Analytical gel filtration was carried out using a Sephacryl 300 (Sigma) column of total volume ( V t ) 49.5 ml, equilibrated in buffer G (50 mM Tris–HCl, 17 mM Tris‐base, 150 mM sodium chloride, pH 7.4 [44]). Proteins were applied (volumes ⩽250 μl) and resolved in buffer G at a flow rate of 1 ml min −1 .…”

The Physical Stability of the Recombinant Tuberculosis Fusion Antigens H1 and H56

“…The formulations for this part of the study were prepared in 10 mM Tris buffer (pH 7.4) because the liposome stability is optimal in this buffer, and it has been used for all preclinical and clinical studies with CAF01. 15,23,24 Because of the high temperature coefficient of Tris leading to a pH shift during heating, 25 experiments were only performed at temperatures up to 50 • C. Over the limited temperature range examined, the pH decreases only one unit, a range over which both protein and liposomes have previously been shown to be stable. The peak positions of the spectra monitored at 15 • C in the presence and absence of liposomes were similar for both H56 and H1, approximately 335-340 nm (Fig.…”

Standard Reference Materials :

“…The pa H of the buffer is then computed from p(a H y c| )°b y the introduction of a conventional individual ionic activity coefficient for chloride: pa H = p(a H Y C| )°+ log Y C| (5) Inasmuch as this quantity, Yc i > nas no independent thermodynamic definition, the Bates -Guggenheim convention [4] has been adopted for the evaluation of log Y C[ :…”

“…This buffer was selected as a physiological pH standard because of its freedom from undesirable side reactions in biological fluids and the similarity of its pH temperature coefficient to that of blood [5]. Although intended as a primary standard, the tris buffer should be regarded as a secondary standard for pH until consistency with the primary standard scale is demonstrated.…”