Chemistry lab equipment: fitting out a synthetic bench in the right order

The order to buy in

1. Containment and services first. Fume hoods, ventilation, gas and vacuum lines, emergency equipment and compliant storage for flammables and corrosives determine what chemistry the laboratory may perform at all. These are building works with long lead times and they cannot be retrofitted around a bench full of instruments.
2. Heating, cooling and stirring. Hotplate stirrers, heating mantles, chillers, a rotary evaporator and a vacuum source cover the great majority of synthetic operations. Buy more stirrer positions than you think you need, because they are the bottleneck in every working synthetic laboratory.
3. Weighing and measuring. An analytical balance on a proper bench, a precision balance for bulk, and volumetric ware at a grade matched to the work. Site the balance before the bench layout is fixed rather than finding a corner for it afterwards.
4. Separation and purification. Flash chromatography, a good supply of columns and solvents, and rotary evaporation with adequate condenser capacity. This is where throughput is won or lost, and under-specifying the evaporator is the classic mistake.
5. Analysis last, and shared where possible. Spectroscopy and chromatography instruments are the largest purchases and are often better accessed through a shared facility until the workload justifies ownership. An instrument used occasionally is a maintenance liability rather than an asset.

Storage, labelling and waste

Compliant cabinets for flammables and corrosives, segregated storage for incompatibles, and a labelling regime that satisfies hazard communication requirements are part of the fit-out rather than an administrative afterthought. Containers must tell the user what they hold and what it does.

Plan waste from the first day: segregated streams, compatible containers, a collection route and a contractor. Laboratories that improvise waste accumulate a problem that becomes expensive and sometimes dangerous to unwind.

Consumables and the standing order

Glassware, septa, syringes, solvents, drying agents and gloves are a continuous cost, and a standing order with an agreed specification is far cheaper and less disruptive than ad hoc purchasing. Standardise the specification before chasing the price.

Keep a deliberate spares holding for the things that stop work: stirrer hotplates, vacuum pump parts, condenser tubing and the common ground glass joints. The cost is trivial against a bench standing idle.

Heating, stirring, and the lab thermometer that tells you the real temperature

A hot plate with a magnetic stirrer is the most used instrument on a chemistry bench, and its useful specifications are the surface material, the top temperature, whether it takes an external probe and whether it controls the medium's temperature rather than the plate's. A plate set to a temperature is not a solution at that temperature.

Thermometers are the other half. A digital probe with a certificate traceable to a national standard, and a stated uncertainty, is what makes a recorded temperature defensible. An uncalibrated thermometer reports a number and proves nothing.

The solvent evaporator, and getting analyte out of a matrix

Evaporating solvent under reduced pressure at a controlled temperature is how a fraction becomes a residue, and the questions are the volume, the number of samples at once, whether the compound is volatile enough to be lost with the solvent and whether it is oxygen or light sensitive.

Getting the analyte out of a solid matrix is the opposite operation. Classical reflux extraction is slow and uses a great deal of solvent; pressurised and microwave systems are faster and need a capital purchase; and supercritical carbon dioxide replaces organic solvent entirely for compounds that dissolve in it.

Supercritical extraction, specified properly

Carbon dioxide above its critical point dissolves non-polar compounds and leaves no solvent residue, which is why it is used for botanical extracts and for analytical extraction. Its selectivity is tuned by pressure, temperature and a small amount of a polar modifier.

Specify it by vessel volume, pressure rating, whether modifier addition and fraction collection are included, and the extraction rate on your own material. It is a pressure system, so the statutory examination regime and the operator training are part of the purchase rather than an afterthought.

Ultrasound does more than mix

A bath cleans and degasses gently; a probe delivers enough energy to disrupt cells, break up agglomerates and emulsify, and that energy also heats the sample and can shear large molecules. Cooling and a pulsed regime are part of the method rather than refinements.

For nucleic acids and proteins the heat and shear matter: over-sonication degrades what you were trying to release. Establish the time, amplitude and cooling on a test sample and then keep them fixed, because this is one of the least reproducible steps in sample preparation.

Counting radioactivity

Gamma emitters are counted in a solid crystal detector with the sample in a tube, which is simple and needs no sample preparation. Beta emitters are counted in a liquid scintillant that converts the particle's energy to light, which means mixing the sample with the scintillant and dealing with quenching.

Both bring a radiation authorisation, a waste route and record keeping that dominate the operating burden. Many laboratories have moved to non-radioactive alternatives for exactly that reason, and the remaining uses are the ones where sensitivity or the absence of a label alternative decides it.

Solid dose handling with tablet counting machines, and software that proposes routes

On a formulation line, counting, dedusting and tooling are where a tablet's quality is protected after compression: consistent count for packing, dust removed so coating adheres, and tooling maintained because a worn punch produces defects that no downstream check can fix.

Retrosynthesis software is a different kind of purchase: it proposes routes to a target molecule from reaction databases and models. It is a chemist's assistant rather than an oracle, and its value depends on the databases behind it and on being read critically.

Chemistry instruments, and the order to buy them in

A chemistry laboratory's instrument list has an order that follows the questions it will be asked. Balances, pH and a stirrer-hotplate are not negotiable. Then separation and identification, HPLC or GC with a UV or flame detector, and a spectrophotometer, which between them answer purity and quantity. Then structure, which means NMR or a mass spectrometer, and those are the two that change the building as well as the budget. Everything after that is specialisation, thermal analysis, titration, particle sizing, bought against a method somebody has written rather than a capability wish.

A hot plate used in laboratory work, and what to check

A laboratory hot plate is specified by the surface, the control and the safety. Ceramic surfaces are chemically resistant and clean easily; aluminium heats more evenly and marks. A stirrer-hotplate's useful spread is the volume range it can actually stir at temperature. The control matters most: a plate with a feedback probe in the liquid holds a set temperature, while one controlling the surface overshoots badly under a small vessel. Safety features to insist on are a hot-surface indicator that stays lit after the power is off, and a housing rated for the solvents nearby.

A supercritical co2 extraction machine and the parameters that matter

A supercritical co2 extraction machine extracts with carbon dioxide above its critical point, which gives a solvent free extract and a tuneable selectivity through pressure and temperature, and a co-solvent is added for polar analytes. Vessel volume, pressure rating and whether fractions can be collected separately are the specifications, and the cost is dominated by the pumps and the safety system.

Common questions

What should a chemistry laboratory buy first?

Containment and services: fume hoods, ventilation, gas and vacuum, emergency equipment and compliant storage. These have long lead times, they are building works, and they determine what chemistry is permitted at all.

How many stirrer hotplates do we need?

More than the initial estimate. Stirring positions are the standing bottleneck in synthetic laboratories, and they are among the cheapest items on the list.

Should we buy our own analytical instruments?

Only when workload justifies it. Occasional use is usually better served by a shared facility or an external laboratory, because an underused instrument still needs service, calibration and someone who knows it.

What labelling is required on chemical containers?

Containers must identify the chemical and communicate its hazards under the hazard communication standard, and the laboratory's chemical hygiene plan should set out how that is applied to working containers as well as to stock.

Is a hot plate set to a temperature the same as a solution at it?

No. Without an external probe controlling on the medium, the plate's set point is not the solution's temperature. For anything temperature-sensitive, control on the medium and record it with a calibrated probe.

Why do my sonication results vary?

Because time, amplitude and cooling are usually not fixed, and the energy heats and shears the sample. Establish the regime on a test sample and keep it constant; over-sonication degrades what you were releasing.

Browse by service class

• Compare Gene synthesis on advertised prices