Method miniaturisation is the squeezing of as many instrumental and analytical parameters as possible to optimise efficiency. Variables that can be examined include extraction solvent, extraction technique, injection onto the column, separation on column, quantification via the detector and finally the cycle time of one analytical run. Further improvements can then come from choice of consumables, process improvements and lab re-arrangements. As we strive to make the method more robust we should improve quality, obtain an equivalent if not better Limit of Detection (LOD) and deliver the result more quickly and hence more cheaply.
Choice of consumables, Process improvements and Lab re-arrangements
How do consumable savings arise?
Looking at miniaturising water analysis methods for PAHs or Total Petroleum Hydrocarbons (TPH) from liquid/liquid extraction to large volume injection, small disposable glass vials (60ml) will replace large cumbersome separating funnels (one litre), saving time, reducing courier costs and negating the need for washing glassware. Similarly, certified EPA vials used in soil analysis - whilst being excellent quality and the industry vessel of choice - are most certainly not the cheapest, other cheaper fit-for-purpose alternatives exist.
Diagram 1: Cumbersome extraction to miniaturised high cost to miniaturised low cost
How do process improvements arise?
Space is often at a premium in older laboratories. After water analysis methods are miniaturised, such small volumes of solvent and such small vessels are used that the space required in a fume cupboard becomes negligible. The extra space can be taken by an efficient soil extraction system that once again took a whole fume cupboard to itself. No queuing means no time loss. The more efficient use of work space can also promote health and safety and might negate the need for a shift system, a shift premium, unsociable working hours and any extra energy costs involved.
How do lab re-arrangements arise?
Allying the space savings and method miniaturisations described in previous paragraphs has led laboratories to regard their operations as manufacturing enterprises. The ideal in any modern lab is to have a “push” ethos. If as many methods as possible have been miniaturised it is perfectly feasible to gear the “front end” of a laboratory into a sample-splitting area. Here, each sample aliquot (whether it be a soil or water sample within an Environmental Lab) will be weighed into a vial that is then used for the extraction, this will save several people constantly going back to the original container, on a shelf or in a fridge, to sub-sample. These aliquots are then pushed down to the extraction department who in turn send the extracts, when completed, on to the instrumental analysts who then provide the results to the reporting teams for final delivery to the customer. If everyone can see the work coming, they are more likely to be focussed on delivery. Old style compartmentalised labs do not promote flow through the system, in fact they are more likely to ensure samples (and analysts!) go missing.
Diagram 2: Floor schematic of push lab v compartmentalised