Expert Buffer Designer

About this guide

Design a buffer, check it, and get a recipe you can weigh out. This takes about three minutes. For how the numbers are calculated, and where they stop being reliable, see the detailed guide.

1. Open a buffer

The first page gives you four ways in:

• Start with an example. The featured example, Deep dive into phosphate buffer, opens a fully worked 50 mM phosphate buffer at pH 7.2 with 150 mM sodium chloride. Click Open example.
• App-defined buffers are a ready-made set for a monoclonal antibody process (mAb Platform), grouped by step: Protein A Capture, Viral Inactivation, AEX Polish, CEX Polish, HIC Polish, Viral Filtration, UF/DF and Formulation. Click a step to filter, then click a card.
• User-defined lists the buffers you have saved.
• Build from scratch · advanced starts a new buffer with every setting open to you.

2. Find your way around

• Left: the Parameters that define the buffer. The Assistant tab beside it holds the chat assistant.
• Right: the results, in seven tabs: Composition, Visualize, Recipe, Report, Sweep, Compare and Library.
• Top: the buffer’s name and whether it’s saved, with Export Recipe, Save As and Save to library. ← Designs takes you back to the first page.

3. Design the buffer

In Buffer Species mode:

1. Choose a Buffer System, such as Phosphate or Tris-HCl. Under it, Makeable pH is the range this system can reach. The Buffering range bar shows how well it buffers at each pH: green is good, amber is marginal, red is poor.
2. Set the Target pH and the Buffer Conc (mM).
3. Choose a Salt and its concentration if you need one.
4. Set the Temperature (°C) you’ll make it at and the Volume (L) you’ll make.
5. Leave Ionic Strength Model on Auto, the default. It chooses the model that suits your buffer’s ionic strength.

The results update as soon as you leave a field. Recalculate re-runs the calculation and also puts a snapshot of the buffer in the comparison tray, ready for Compare.

To enter the exact compounds yourself, switch to Custom Compounds. There you can also tick Enable pH adjustment, and the app works out how much acid or base brings the buffer to your target pH.

4. Check the result

• Composition shows the final pH, what your pH meter should read (Meter pH), the ionic strength, how much of each compound goes in (mM and g/L), and which charged forms are present.
• Visualize shows how the pH moves with temperature and with salt, the buffer capacity across pH, which species are present at each pH, and how far the pH drifts if a weighing is 10% off.

If a ⚠ notice appears above the results, read it. It means the calculation has gone outside the range where it is reliable, and it usually offers a one-click fix.

5. Get the recipe

Recipe turns the design into a preparation worksheet for the volume you set. Pick the form of each reagent you have on the shelf, anhydrous or a hydrate, and the masses update. Its pH check uses the reading your meter should show. Fill in the batch ID and preparer, then use Open PDF, CSV or Copy.

6. Ask “what if?”

Sweep varies one or two inputs and shows what happens, without changing your buffer. Two good places to start:

• What happens in the cold room: vary Temperature (°C) from 4 to 40 with make once, read at each. This shows how the pH of the buffer you made drifts when you use it at another temperature.
• Which species at pH 5: vary Buffer System to list every system that buffers well at the pH you choose.

Click + compare on any row to send it to Compare, which shows up to three buffers side by side.

7. Save and report

• Save to library keeps the buffer, with a description and tags if you want them. Save As keeps a copy under a new name. Saved buffers appear on the first page under User-defined, and in the Library tab, which the other apps in the suite can read from.
• Report builds a PDF: the design, quality ratings, charts, composition, corrections and the worksheet. Tick the sections you want, then Download PDF.

Need more?

• The Assistant can set up a buffer from a plain-language request and read back its recipe and pH, when a model is connected.
• The detailed guide explains how each number is calculated, the ranges it’s valid for, and what the model leaves out.