A practical starting list of reagents, standards and consumables for a new quality control laboratory, and how to keep them fit for use.
A new QC laboratory usually over-buys glassware and under-buys the reagents that determine whether results are defensible.
Grades, and when each is appropriate
Analytical Reagent (AR) grade is the default for quantitative analysis — titrations, standard preparation, sample digestion. HPLC grade solvents are required for chromatography, where UV transparency and low residue matter. Technical grade is adequate for cleaning and non-quantitative work. Buying AR grade for glassware rinsing wastes money; buying technical grade for a titration wastes the result.
The core reagent list
For a general QC laboratory: sodium hydroxide pellets AR and hydrochloric acid AR for acid-base work; a primary standard such as potassium hydrogen phthalate for standardisation; methanol and isopropyl alcohol for extraction and cleaning; buffer solutions at pH 4, 7 and 10 for meter calibration; and appropriate indicators — phenolphthalein and methyl orange cover most titrimetric needs.
Primary standards deserve real care
Your entire chain of results traces back to primary standards. Buy small quantities, store them sealed in a desiccator, and never return unused material to the bottle. Record the lot number against every standardisation.
Buffer solutions expire
pH buffers absorb carbon dioxide and support microbial growth once opened. Date the bottle on opening, discard three months later regardless of appearance, and never pour used buffer back. A meter calibrated against a degraded buffer produces confidently wrong numbers.
Water quality is a reagent decision
Type II deionised water is the minimum for most analytical work. Tap water carries chloride, calcium and organics that interfere with titrations and chromatography. If your results drift inexplicably, test the water before blaming the method.
Certificates and traceability
Every AR grade reagent should arrive with a batch Certificate of Analysis. File them — an auditor will ask for the COA of the reagent used in a specific test on a specific date. Maintain a reagent register recording receipt date, opening date, lot number and expiry.
Storage discipline
Segregate acids from bases, keep oxidisers away from flammables, store solvents in a flammables cabinet, and keep light-sensitive reagents in amber glass. Label every prepared solution with contents, concentration, preparer and date. Unlabelled bottles are disposal costs waiting to be incurred.
