Expert Buffer Designer — User Guide

Step 1 — Pick a buffer species

Pick a buffer species (single, dual, etc.) using the autocomplete input. As soon as you pick the species, the tool populates the input for you in the correct format.

Step 2 — Format the natural-language input

Your input should follow this format:

• Buffer concentration: a number followed by "mM" — e.g. "50mM".
• Buffer species: the name of the buffering species — e.g. "Phosphate".
• Salt concentration (optional): a number followed by "M" — e.g. "0.1M".
• Salt name (optional): the name of the salt — e.g. "Sodium Chloride".
• pH: the keyword "pH" followed by the target — e.g. "pH 7.0".

A complete input might look like: "50mM Phosphate, 0.1M Sodium Chloride, pH 7.0".

Step 3 — Generate your recipe

Click Get Recipe. This triggers several events:

• Status message: reads "Done" on success, or detailed feedback if there are issues.
• Solution list: the resulting buffer is added to your solution list.
• Buffer recipe: a detailed recipe is provided.
• Buffer analysis: a comprehensive analysis including compound concentrations, ion concentrations, ion-species concentrations, and a heat-map showing the impact of variability in compound concentrations.

Step 1 — Select acidic and basic compounds

Select your acidic compound from the first drop-down (which contains both buffering and non-buffering compounds). If you choose a non-buffering compound, ensure you select a buffering compound from the basic-compound list. Then select your basic compound from the second drop-down. If the basic compound does not contain the same buffering species as the acidic compound, its concentration is adjusted to achieve the target pH.

Step 2 — Specify the target buffer-species concentration

Enter the target concentration for the buffering species in molar units — the concentration of the buffering species in the final buffer. If both compounds contain the same buffering species, their concentrations are adjusted to achieve this target.

Step 3 — Choose a salt compound (optional)

Optionally select a salt (currently Sodium Chloride, Sodium Sulfate, or Ammonium Sulfate) and enter its concentration in molar units.

Step 4 — Input the target pH

Enter your desired target pH. The acidic and basic compound concentrations are adjusted as necessary to achieve it.

Step 5 — Generate your recipe

Click Get Recipe to display the calculated recipe and analysis.

Note: certain compound and concentration combinations limit the achievable pH range due to chemistry; an error will report the achievable range. Ionic-strength corrections are not accurate beyond 0.4M. The GenAI Designer does not have this limitation, but a very broad range of concentrations may yield impractical recipes.

Pick the acidic and basic compounds and their concentrations (in molar), optionally add a salt compound and concentration, then click Calculate pH. The request is sent to the server and the pH and details are populated. Use this to calculate the pH of a composition you specify, rather than targeting one.

The Super Calculator provides versatile capability: add up to three buffer compounds and one salt compound, and optionally auto-adjust the solution with acid or base to a target pH (the tool picks Sodium Hydroxide or Hydrochloric Acid automatically). Alternatively, simply calculate the pH of the composition you specify.

Use caution when choosing compounds — it gives complete flexibility, with the only constraint being that you can't choose the same compound twice. You can choose three basic compounds, or two acidic and one basic, and so on. The choice is yours.

The GenAI Buffer Designer is flexible with input. It first checks that the input has one or more buffer species and won't proceed without it. Concentration can be specified as 0.4M or 40mM; if you skip units, a number greater than 1 is read as mM and less than 1 as M. You can specify concentration in parentheses. Specify salts by compound name ("salt" works for Sodium Chloride); the only salts available are Sodium Chloride, Sodium Sulfate, and Ammonium Sulfate. You must use the word "pH" with a value somewhere in context. For example, this yields a valid recipe: "Yo dude can you whip me up a seventy one phosphate with a good chunk of hundred Sodium Chloride with an awesome pH of seven?"

Both compounds containing the same buffering species — e.g. Sodium Phosphate Monobasic and Sodium Phosphate Dibasic, where both contain Phosphate (the buffering species) and Sodium (the counter-ion). In the Classic Designer, pick an acidic and a basic compound that share the buffering species and counter-ion, then specify the target buffer concentration and pH; the engine determines the proportion of each compound. With GenAI, simply specify e.g. "40mM Phosphate ... with a pH of X" and it picks the appropriate compounds.

One compound only containing the buffering species — e.g. Sodium Phosphate Monobasic with Sodium Hydroxide, where the hydroxide supplies the counter-ion only. In the Classic Designer, pick the compound with the buffering-species/counter-ion salt and the other with only the counter-ion, then specify concentration and pH. This case is not currently achievable with GenAI input.

Two buffering species, achieved with two compounds, each containing only the "pure form" of a species — one contributing positive (basic) ions and the other negative (acidic) ions. A popular example is Acetate–Tris, from Acetic Acid and Tris Base. In the Classic Designer, choose Acetic Acid first and Tris Base second; the target concentration refers to the buffering species in the acidic component, and the engine finds the concentration of the second compound to hit the target pH.

With GenAI you can say "Make a 50mM Acetate Tris buffer, with pH of 5", and you can also do the reverse — "Make a 50mM Tris Acetate buffer, pH 8" — to target 50mM Tris and adjust Acetic Acid to achieve the pH.

With each option you can optionally add a salt and specify its concentration. Salt concentration, along with the buffering compounds, plays a critical role in the ionic strength of the solution, which affects the dissociation constant of the buffering species and hence the pH.

When certain compounds are chosen with specified target concentrations, only a limited pH range can be achieved due to the chemistry; an error reports the achievable range. General guidance: pick concentrations less than 0.4M and choose a pH within two units of the pKa of the primary buffer species.