The grade on the bottle is the most consequential thing on the label. It decides whether your result is defensible in an audit, and it is where most laboratories either overspend or get caught short.
One thing worth knowing before you read the list. Grade names are not standardised across manufacturers. Some Indian producers define LR in their published legend but never print it on a label — their working equivalent is Extra Pure. Some print GR where others print AR. And the European “Ultra Dry” label appears in Indian catalogues as Specially Dried or Anhydrous Dried.
When you are comparing quotations, compare the assay figure and the impurity table. The letters are a shorthand, not a specification.
Certified assay, itemised impurity limits, batch Certificate of Analysis. What you buy when the result goes on a report.
The working grade for quantitative analysis. The label carries an assay figure and maximum limits for named impurities, and the batch is covered by a Certificate of Analysis. This is what an accredited laboratory buys for anything that produces a reportable number.
Use when Titrations, gravimetric analysis, standard preparation, any test whose result goes on a report or into a NABL scope.
Meets the specifications published in ACS Reagent Chemicals. The ACS monograph fixes both the assay and the individual impurity ceilings, so batches are comparable across manufacturers — which matters when a method was validated on someone else’s reagent.
Use when Methods that name ACS reagents explicitly, and inter-laboratory work where reagent equivalence has to be demonstrable.
Same standard as AR/ACS, labelled without the separate AR designation. Common on indicators and stains.
Use when Where a method cites "ACS reagent grade" by name.
Functionally equivalent to AR. The designation descends from the European catalogue tradition and is the dominant label on Otto Chemie products, where Loba would print AR. Compare the assay and impurity table rather than the letters when substituting one for the other.
Use when Analytical work, as an AR equivalent.
Specified on the properties that wreck an instrument method — UV cut-off, gradient baseline, residue on evaporation, particulate content, metal background.
Specified on gradient-elution baseline, UV cut-off, residue after evaporation and particulate content — the four things that wreck a chromatogram. Membrane-filtered before filling.
Use when HPLC and UHPLC mobile phases, sample dilution for chromatography.
Everything HPLC grade specifies, plus controls on alkali-metal and phthalate content that would otherwise produce adduct ions and raise the baseline. Usually supplied in glass to avoid leachables from plastic.
Use when LC-MS and LC-MS/MS, trace quantitation, proteomics.
Controlled for the volatile impurities that appear as ghost peaks in gas chromatography. Headspace variants additionally control high-boiling residue.
Use when Gas chromatography, residual-solvent testing, headspace analysis.
Specified on transmittance across the working wavelength range so the solvent itself does not absorb where the analyte does.
Use when UV/Vis and IR spectroscopy, fluorescence, NMR solvents.
Tested by GC-ECD against a pesticide reference panel. The specification is about what is absent, not what is present.
Use when Pesticide residue analysis in food, water and agricultural samples.
Tested against every test in a named monograph. A regulatory instrument, not a purity claim.
Tested against every test in the IP monograph for that substance, with a Certificate of Analysis referencing it. A pharmacopoeial grade is a regulatory instrument, not a purity claim — it means the material passed a specific, named set of tests.
Use when Pharmaceutical QC, formulation development, anything inspected under Schedule M or supplied into a licensed manufacturing process.
As IP, against the BP monograph. Often specified for export formulations or where a client’s method was written to BP.
Use when Pharmaceutical QC where the method or registration cites BP.
As IP, against the USP monograph. Frequently required for US-bound formulations and for methods transferred from a US site.
Use when Pharmaceutical QC where the method or registration cites USP.
Purity and contaminant limits appropriate to substances used in or on food.
Use when Food processing, food additive testing.
Purity defined by what is absent — trace metals, water, nucleases — or by a property such as certified dye content.
Acids and reagents purified so that the reagent blank does not swamp the analyte. Specified in parts per billion, per element, and supplied in containers chosen not to contribute metals back.
Use when ICP-MS, ICP-OES, AAS, trace metal digestion and sample preparation.
Ultra-low metallic and particulate content for wafer processing and electronics cleaning.
Use when Semiconductor fabrication, electronics manufacturing.
A statement of composition rather than of purity — it tells you the molecular weight to use in a calculation. Always read it together with the purity grade.
Use when Where the hydrate would upset stoichiometry or introduce water.
Dried and packed under inert gas, usually with a septum closure, and labelled with a maximum water content in ppm. Note the Indian catalogue names: "Specially Dried" and "Anhydrous Dried" rather than the "Ultra Dry" wording used by some European brands.
Use when Moisture-sensitive synthesis, Grignard and organometallic chemistry, Karl Fischer titration.
Stains carry a stated dye content — the fraction of the powder that is actually the colourant. Two bottles of the same stain at different dye contents give visibly different results at the same recipe.
Use when Histology, cytology, microbiological staining.
Specified on heavy metals and on substances that interfere with enzyme activity or cell viability.
Use when Enzyme assays, cell culture media preparation, biochemical research.
Tested for nuclease and protease activity, and usually for DNA contamination. The certificate is the product.
Use when PCR, electrophoresis, nucleic acid extraction, cloning.
Dehydrated culture media and their raw materials — peptones, extracts, agar — released against a growth-promotion test rather than a chemical assay. The figure that matters is not purity but whether the named organism grows, at the expected rate, with the expected colony morphology, against a reference strain. A medium can be chemically immaculate and still fail growth promotion, which is why an assay percentage on a label tells you almost nothing here.
Use when Any medium used to isolate, enumerate or identify organisms — and mandatory where the method is pharmacopoeial.
Correct, and considerably cheaper, for a large share of routine laboratory consumption.
Assay is stated but the impurity profile is looser than AR and is not always itemised. Worth knowing: several Indian manufacturers do not print "LR" at all — their equivalent tier is labelled Extra Pure. Do not assume the two are interchangeable on paper even where they are in practice.
Use when Cleaning solutions, buffer bulk-up, undergraduate teaching labs, preparative chemistry where trace metals do not matter.
The commonest grade in the Indian trade and the practical equivalent of LR. Purity is stated; the impurity table is shorter than AR. Substantially cheaper, and correct for a large share of routine laboratory consumption.
Use when Routine preparation, non-reportable work, bulk consumption.
Intended as a starting material or reagent in a synthesis, where the product is purified downstream. Assay is adequate; trace analysis is not the point.
Use when Organic synthesis, process development, pilot work.
Purity is defined by performance — a sharp, correctly-placed endpoint — rather than by a bare assay figure.
Use when Volumetric titration.
No analytical specification. Appropriate for plant use, cleaning and process applications where the impurity profile is irrelevant.
Use when Industrial process use, bulk cleaning, effluent treatment.
Send us the method or the standard. We will tell you the grade it requires — and where you are currently buying above it.
