The fastest way to read a lab report is to ignore the headline number and find its basis first: the same glutamate result can be printed as milligrams per gram, per 100 grams, or per serving, and converted to an MSG equivalent in two different forms — and every one of those printings is a different-looking number for identical chemistry. This page shows you how to unpick a report line by line, with a worked example that is clearly illustrative, so the next report you receive reads as information instead of authority.
The 30-second method
Find five things, in this order. One: the analyte — the substance measured, for example glutamate, reported as glutamic acid. Two: free or total — whether the amino acids were measured as they occur in the food, or after hydrolysis broke the protein apart. Three: the basis — the unit and denominator, such as mg/g. Four: the form of any conversion — for MSG equivalents, anhydrous or monohydrate. Five: the evidence behind the number — the chromatogram, the instrument trace, and whether a matrix-effect check was run on your sample. If any of the five is missing, ask for it before you compare the result to anything.
Bases: the denominator is the meaning
A reporting basis states how much sample the amount refers to. Milligrams per gram (mg/g) says: in each gram of your sample, this many milligrams of the analyte were found. Milligrams per 100 grams (mg/100 g) is the same measurement scaled by 100 — a result of 2 mg/g is 200 mg/100 g. Neither is more correct; food labels often favour per 100 g, while formulation work often favours per gram. Milligrams per serving adds a further step that depends entirely on the serving size someone chose, so a per-serving figure can be made to look small or large without the chemistry changing at all. When you compare two reports, convert both to the same basis first. If a report gives only per-serving numbers without the serving weight, the conversion back is impossible — ask for the underlying basis.
Dry and wet bases add one more trap for moist foods. A result expressed per gram of sample as received includes the water in that gram; a result per gram of dry matter removes it. For a dry seasoning the difference is small. For a sauce it can be substantial. A careful report states which it used. This article does not assign your sample to either — it tells you to check which one your report claims.
The MSG equivalent, done carefully
Glutamate is often reported as glutamic acid, but recipes and labels talk about MSG — monosodium glutamate. Converting between them is a molar-mass ratio: you scale by the mass of one mole of MSG divided by the mass of one mole of glutamic acid. A mole is simply the chemist's counting unit for molecules, and molar mass is the weight of that standard count, in grams per mole.
The cited masses are: glutamic acid, 147.13 g/mol; anhydrous MSG, 169.11 g/mol; and MSG monohydrate — the common commercial form, which carries one water molecule — 187.13 g/mol. Those values come from the PubChem compound pages for glutamic acid and monosodium glutamate. The conversion factors follow directly: to express glutamic acid as anhydrous MSG equivalent, multiply by 169.11 / 147.13, about 1.149. To express it as MSG monohydrate equivalent, multiply by 187.13 / 147.13, about 1.272. The two equivalents differ by roughly a tenth, which is exactly why a report must state its form. An "MSG equivalent" with no form named is an unfinished sentence.
Worked example — illustrative, not laboratory data. Suppose a report states free glutamate as 10.0 mg/g, expressed as glutamic acid. As anhydrous MSG equivalent that is 10.0 × 1.149 = 11.5 mg/g, rounded. As MSG monohydrate equivalent it is 10.0 × 1.272 = 12.7 mg/g. Same sample, same measurement, three defensible numbers: 10.0, 11.5, and 12.7 mg/g. None of them is the "real MSG you added" — the measurement covers free glutamate from all sources in the sample, not only added MSG powder. If you remember one line from this page, make it that one.
Note what this conversion does not do. It does not involve sodium content, it does not assess safety, and it does not turn a free-glutamate result into a total-glutamate result. Hydrolysis — the total test, AA-T, which treats the sample with 6 N hydrochloric acid at 110 °C for 24 hours — changes what is measured, not just how it is printed.
What a complete report from here shows
A report for the AA-1 free panel covers 19 amino acids plus ammonia, measured by AQC (AccQ-Tag) derivatization with HPLC-UV, with cysteine excluded because it needs a separate AA-3 workup. Expect per-analyte results with their basis, the chromatogram behind each number, and — where matrix-effect qualification was commissioned — the spike-recovery finding for your sample and any correction applied. Matrix-effect qualification is priced per sample and matrix on inquiry; a recent single-sample seasoning project with full qualification was $350. The panel itself costs $150 per sample for liquids, $180 for powders, $150 flat for first-time customers, and $125 per sample at 25 or more samples per month. The laboratory is in Davis, California, is validating now and reserving pilot slots, and is not GLP, GMP, or ISO/IEC 17025 accredited; results are for your own decisions, not regulatory submission.
Your next step
Take any report you already have and run the five-point check above. If a basis or a form is missing, email the issuing lab and ask for it in writing. If you are commissioning a new test, settle the basis before the sample ships — info@openchemworks.com will confirm the reporting basis for an AA-1 order before you send anything.
Frequently asked questions
My two reports disagree. Is one wrong?
Not necessarily. Put both on the same basis and the same form first. Only compare after that conversion.
Which MSG form should I ask for?
Ask for the report to state glutamic acid as the primary result and name the MSG form used for any equivalent. Monohydrate is the common commercial form, but the choice must be explicit, not assumed.
Does mg/g mean the same as percent?
No. Percent is grams per 100 grams. A result of 10 mg/g is 1 g per 100 g, i.e. 1%. Converting explicitly prevents a tenfold misreading.
Can I convert a per-serving label figure back to mg/g?
Only if you know the exact serving weight in grams. Ask for it.
References
- PubChem — L-Glutamic acid (CID 33032) — Molar mass 147.13 g/mol, cited for the MSG-equivalent conversions.
- PubChem — Monosodium glutamate (CID 23672308) — Anhydrous MSG 169.11 g/mol; monohydrate 187.13 g/mol.
- PubChem — L-Glutamic acid (CID 33032) — Molar mass 147.13 g/mol, cited for the MSG-equivalent conversions.
- PubChem — Monosodium glutamate (CID 23672308) — Anhydrous MSG 169.11 g/mol; monohydrate 187.13 g/mol.
- Waters — Derivatization of Amino Acids Using Waters AccQ-Tag Chemistry — Method background for AQC derivatization and HPLC-UV amino acid analysis.
- OpenChemWorks — Pricing — Published service and pricing copy (2026).
OpenChemWorks Laboratory · Reviewed by the laboratory director, PhD chemist · Published October 16, 2026