Hamilton vs Tecan Troughs: A Dead Volume Comparison

Two instruments, two trough designs, one problem

Dead volume in reagent troughs is one of the most common sources of protocol failure in automated liquid handling, and it's consistently underestimated. When comparing Hamilton and Tecan workflows, most attention goes to scripting language differences (Venus vs FluentControl) or deck capacity. Trough geometry rarely comes up. It should.

Hamilton and Tecan have made different design choices for their standard reagent reservoirs, and those choices produce meaningfully different dead volume profiles. Understanding the difference matters if you are:

• Writing protocols for both platforms
• Migrating a method from one instrument to the other
• Choosing a trough format for a shared-instrument workflow
• Debugging a run failure caused by reagent depletion

The core geometric difference

Neither design is strictly superior. They make different trade-offs, and each suits specific scenarios better.

Dead volume figures: side by side

These are representative figures for standard trough formats under typical conditions. Always verify against your specific labware definition and confirm empirically during method development.

At high fill volumes, the tapered Tecan trough is more efficient per mL of capacity; the dead volume as a percentage of total volume is lower. At low fill volumes or with wide tips, the Hamilton flat-bottom design becomes more predictable and often more efficient.

When the Hamilton flat-bottom reservoir wins

Predictability. For protocol development and dead volume calculation, a flat-bottom reservoir is the easier surface to work with. You know exactly how much liquid is left at any aspirate position because the cross-sectional area is constant. The relationship between liquid height and remaining volume is a simple multiplication.

Multi-channel consistency. When running 8 channels from a flat-bottom trough, all 8 tips are over the same liquid cross-section. The level drops uniformly across the full base, and all channels see the same liquid height. There's no penalty for tip position across the Y-axis of the trough.

LLD reliability at low volumes. Capacitive LLD works well across the full volume range of a flat-bottom reservoir because the liquid surface area doesn't change. The sensor always has a consistent geometry to detect. In a tapered trough at very low fill levels, the liquid surface is confined to the narrow channel, which can produce less reliable LLD signals.

Robustness to labware definition errors. If your labware definition has a small error in the Z-bottom value, a flat-bottom reservoir is more forgiving. An error of 0.5 mm in a flat-bottom reservoir wastes approximately 0.5 mm x base area of liquid. In a tapered trough, the same 0.5 mm error in Z-bottom may mean the tip misses the taper channel entirely and aspirates against the sloped wall.

See Dead volume in Hamilton reagent reservoirs for the full geometric breakdown.

When the Tecan tapered trough wins

Extending the low-volume aspiration window. At the very bottom of the fill range, the tapered design concentrates remaining liquid into the channel. A well-designed tapered trough with the correct labware definition can aspirate from volumes that would leave a visible film in a flat-bottom reservoir. This is most relevant when working with reagents that are genuinely limited in supply.

Higher total capacity per deck position. Tecan troughs are typically available in 100 mL formats, whereas common Hamilton reservoirs run to 50 mL. If your workflow requires large reagent volumes per carrier position, the Tecan format provides more headroom before you hit dead volume constraints.

Surface tension effects at low volumes. In a flat-bottom reservoir, very low remaining volumes produce a thin, wide film. Surface tension can impede aspiration and cause the robot to draw partially from the meniscus periphery. In a tapered trough, the same volume is concentrated in a small cross-section with a well-defined meniscus, which is easier to aspirate from.

See Dead volume in Tecan reagent troughs for the full taper geometry breakdown.

The migration trap

If you're migrating a method from a Hamilton STAR to a Tecan Fluent, or vice versa, dead volume is one of the first parameters to audit and one of the most commonly overlooked.

A protocol written for a Hamilton 50 mL flat reservoir might add 3 mL as a dead volume buffer. If that method is migrated to a Tecan tapered trough loaded with 50 mL of reagent, the same 3 mL buffer may be insufficient at the specific LLD sensitivity and tip configuration used on the Fluent, or it may be excessive. The geometry has changed; the buffer must be recalculated.

Two specific migration risks:

Under-buffering on Tecan with multi-channel aspirations. If the Hamilton method was run with single-channel aspirations (and dead volume calculated accordingly), migrating to an 8-channel workflow on the Fluent without adjusting for the multi-channel position penalty in the tapered trough will produce a run failure before the nominal dead volume is reached.

Over-buffering on Hamilton after migrating from Tecan. Tecan trough datasheets sometimes specify conservative dead volumes that account for the worst-case tip/position scenario. If you carry that figure directly to a Hamilton flat-bottom reservoir calculation, you may load unnecessarily large volumes of expensive reagent.

Labware definitions and teaching: platform-specific differences

Both Hamilton Venus and Tecan FluentControl store labware as geometry definitions, but the workflow for verifying them differs.

Hamilton Venus. Labware definitions are stored in the Venus library. The Z-bottom is defined as a distance from the deck reference. Teaching is done via the carrier teach process or the Calibrate Carrier step. For flat-bottom reservoirs, a 0.5 mm error in teaching matters less than for tapered troughs, but should still be verified. For a full walkthrough of how this works on the Hamilton side, see the Venus worktable and teaching your deck.

Tecan FluentControl. Labware is stored in the FluentControl labware library. The ZBottom value is the critical parameter for trough aspiration. Teaching is performed via the labware editor or the teach wizard. For tapered troughs, the centreline Y-position must also be confirmed; the aspiration point is not the vessel centre in all cases.

On both platforms: use the manufacturer's official labware definition as the starting point, then verify empirically. Community-shared labware files vary in quality, and a geometry error in a trough definition will systematically cause problems across every run.

A practical decision guide

Summary

The Hamilton flat-bottom reservoir is the more predictable and forgiving trough for protocol development. Its geometry is linear, its dead volume is calculable, and its LLD behaviour is consistent across fill levels. The Tecan tapered trough can extend aspiration to lower absolute volumes when correctly defined and taught, but it introduces non-linear geometry, tip-width sensitivity, and multi-channel position effects that must be explicitly accounted for.

Neither is always the better choice. Both require correct labware definitions, taught positions, and deliberate dead volume calculations. The 10% rule of thumb is a useful starting estimate, but it should never be the final word when the reagent is expensive, the run is long, or the margin between working volume and dead volume is small. For the equivalent problem in plates rather than troughs, see Dead volume in microplates.