Tris exhibits significant temperature sensitivity. Its pKa shifts by −0.028 units per °C. A solution titrated to pH 7.40 at 25 °C will read approximately pH 7.99 at 4 °C. Always adjust pH at the intended working temperature.

Good's buffers (HEPES, MOPS, PIPES, MES, ACES, BES, TES, TAPS, EPPS, TAPSO, MOPSO, DIPSO, HEPPSO, POPSO) exhibit minimal temperature coefficients (|ΔpKa/°C| ≤ 0.020) and are recommended for experiments conducted across a range of temperatures.

Glycylglycine and CAPSO also show substantial temperature dependence (ΔpKa/°C ≈ −0.028 and −0.032 respectively).

Phosphate buffers precipitate divalent cations (Ca²⁺, Mg²⁺, Mn²⁺, Zn²⁺) as insoluble phosphate salts. Avoid PBS in assays requiring these metals.

Tris chelates Cu²⁺ and weakly coordinates other transition metals. Glycine and Glycylglycine form stable complexes with several transition metals. For metalloenzyme or metal-dependent assays, use HEPES, MOPS, or PIPES, which exhibit negligible metal-binding capacity.

Borate forms covalent complexes with cis-diols (sugars, nucleotides, glycoproteins). Citrate chelates Fe³⁺ and Ca²⁺. Imidazole coordinates Cu²⁺, Zn²⁺, and Co²⁺ — exploited in IMAC (immobilised metal-affinity chromatography).

ADA forms complexes with some divalent metals; avoid in assays sensitive to metal chelation.

Autoclavable (121 °C, 15 min): Tris-HCl, PBS, Citrate, Acetate, SSC, TAE, Tricine, Bicine, Glycine-HCl, Glycine-NaOH, Glycylglycine, Borate, Carbonate, Cacodylate, Imidazole, Bis-Tris

Filter-sterilise only (0.22 µm membrane): HEPES, MOPS, PIPES, MES, ACES, BES, TES, TAPS, EPPS, CAPS, TAPSO, MOPSO, DIPSO, HEPPSO, POPSO, CHES, CAPSO, AMPSO — zwitterionic (Good's) buffers degrade, discolour, or generate cytotoxic by-products at 121 °C.

Re-verify pH after autoclaving Tris-based solutions; thermal decomposition causes a transient pH shift.

Tris interferes with Bradford (Coomassie G-250), BCA, and Lowry protein quantification assays. Substitute HEPES or phosphate buffer.

HEPES generates reactive oxygen species (ROS) under UV irradiation; avoid in photochemistry or oxidative-stress-sensitive assays. Piperazine-containing buffers (PIPES, HEPES, POPSO, EPPS) can also form radicals.

Borate inhibits many enzymes and cross-links RNA via cis-diol complexation. Avoid in enzyme kinetics or RNA work.

Phenol Red (pH 6.8–8.4, yellow → red) is the standard colorimetric indicator for mammalian cell culture media.

Sodium cacodylate (dimethylarsenic acid) contains arsenic. It is acutely toxic by ingestion, inhalation, and skin contact. IARC classifies arsenic compounds as Group 1 carcinogens.

Handle exclusively in a fume hood with appropriate PPE (nitrile gloves, lab coat, safety goggles). Never combine with acids — liberates highly toxic dimethylarsine gas.

Cacodylate is the preferred buffer for electron microscopy fixation (0.1–0.2 M, pH 6.2–7.4) because it does not react with aldehyde fixatives (unlike Tris) and avoids the organelle-damaging phosphate concentrations of Sørensen's buffer. It is also used in protein crystallography where phosphate interference is problematic.

Dispose of cacodylate waste through approved hazardous arsenic waste streams only.

13 new buffer systems added in this version: Cacodylate, Bis-Tris, ADA, MOPSO, Imidazole, DIPSO, TAPSO, HEPPSO, POPSO, Glycylglycine, AMPSO, CHES, and CAPSO.

Bis-Tris — widely used in native PAGE and chromatography (Bis-Tris/MES or Bis-Tris/MOPS gel systems).

Imidazole — essential for His-tag purification by IMAC; competitive elution with 250–500 mM imidazole.

CHES / CAPSO / AMPSO — fill the high-pH gap between TAPS (8.40) and Borate (9.24), critical for alkaline-range enzyme studies and Western blot transfer at pH 10–11.

Data sourced from Sigma-Aldrich Buffer Reference Center, Good et al. (1966, 1972, 1980), CRC Handbook, and NCBI PubChem Compound Database.