Amino acid analysis for spent media

What spent media tells you

A spent sample is typically a clarified supernatant drawn from a culture at a stated day and condition. It contains the amino acids the culture did not use, depleted levels of the ones it consumed heavily, and metabolic products the culture released — including ammonia, which accumulates both from cell metabolism and from chemical decomposition of glutamine in the medium itself.

Because it is a time-stamped outcome, sampling discipline defines its value. A day-7 sample and a day-12 sample from the same run are different statements. A time course shows depletion curves — which amino acids fall early, which persist, and when one runs out. Spent media also carries debris and protein unless clarified, so preparation is part of the measurement and is recorded.

In spent media, three readings do most of the work. First, depletion: amino acids that fall toward exhaustion are candidate limits on the culture, and candidates for feed attention. Second, persistence: amino acids that stay high throughout were supplied beyond what the culture used at that rate — a formulation cost with no benefit. Third, the glutamine–ammonia pair: glutamine is consumed by cells and also decomposes chemically to pyroglutamate and ammonia. The useful question is the rate and balance, because accumulated ammonia is associated in the literature with inhibited CHO growth and reduced productivity. We report the pair as measured; we do not attribute a specific batch's performance to ammonia without your culture data alongside.

Cysteine is excluded from AA-1 and requires a separate AA-3 workup. Pyroglutamate is not a panel analyte; we track glutamine loss and ammonia rise.

Who sends spent media

Upstream process development scientists and cell culture teams. Fresh media analysis verifies a formulation; spent media analysis reads a culture's behaviour. If your sample has not touched cells, the fresh cell culture media page is the right one.

• A batch underperformed and the feed strategy needs evidence instead of habit
• A process is being characterised before scale-up or transfer
• A time course needs depletion curves, not a single endpoint
• A fresh-versus-spent delta is the only way to see what the cells actually consumed

What the report shows

• Each measured amino acid listed individually, plus ammonia, on a stated reporting basis
• The chromatogram behind each number
• Time-course results presented sample by sample, in the order and labelling you supplied
• A plain statement of what was and was not matrix-qualified for your sample

How it works

Published prices

Spent media is a liquid: AA-1 is $150 per sample, and first-time customers pay $150 flat. At 25+ samples per month the rate is $125 per sample. Each time point is one sample; a matched fresh-media baseline is one more, and usually makes the rest interpretable. AA-T is listed for completeness — total is rarely the spent-media question, since consumption acts on the free pool.

Frequently asked questions

Why not just analyse the fresh medium?
Fresh analysis verifies what you made. It cannot show what cells consumed or what accumulated. Spent analysis is the consumption record — the delta between the two is the insight.

How many time points should I send?
Enough to show the shape of depletion for your question. A single endpoint shows leftovers; a series shows curves. The 5-sample pilot suits one run sampled at five points, or fewer points plus a fresh baseline.

Does high ammonia explain my viability dip?
Not from our report alone. Ammonia accumulation is associated with growth inhibition in the literature, but attributing a specific event needs your culture data next to the profile.

Are you GLP or GMP?
No. We are not GLP, GMP, or ISO 17025 accredited, and we do not imply otherwise.