eric-hunt Echo 525 Pick List Design
This skill documents the idiomatic format for an Echo 525 pick list — the target to design toward, sourced from Beckman Coulter's own sample pick lists and instrument documentation.
Instrument limits
| Description | Specification |
|---|---|
| Drop transfer resolution | 25 nL |
| Volume transfer range | 25 nL – 5 µL, one well to one well.25 nL – 45 µL, one well to many wells.Actual range depends on fluid type and assay (destination) plate. |
Source plate / labware selection
Compatible source plates for the Echo 525:
| 384PP Plate | 384PP Plus Plate | 384LDV Plus Plate | Echo Qualified Reservoir | |
|---|---|---|---|---|
| Number of wells | 384 | 384 | 384 | 6 |
| Surface treated | No | Yes | Yes | Yes |
| Stated volume range (µL) | 20–65 | 20–65 | 4.5–14 | 250–2800 |
| Stated working volume (µL) | 45 | 45 | 9.5 | 2550 |
| Actual volume range (µL) | 24–62 | 24–62 | 6–12 | 300–2500 |
| Actual working volume (µL) | 38 | 38 | 6 | 2200 |
"Stated" vs. "Actual": stated figures come from the datasheet; actual figures are the empirically-validated, more conservative numbers recommended by New England Biolabs scientists. Prefer actual working volume when sizing source wells for a method.
The 384PP Plus plate is the preferred general-purpose source plate; the 384PP plate may compromise accuracy/precision for some fluid types and destination plates. 384PP Plus and the Echo Qualified Reservoir are Echo 525-only (not compatible with other Echo models). Beckman Coulter recommends 384PP Plus over 384PP for 1536-well destination targets.
Calibration (Source Plate Type) selection
The Source Plate Type string required by the Echo — e.g. 384PP_AQ_BP, 384LDV_AQ_GP, 6RES_AQ_BP2 — encodes both the physical plate and the fluid's composition (surfactant/CMC, glycerol, protein). It is not just the plate's part number; a given physical plate has several valid calibration strings depending on what's in it.
Prefix by plate, suffix by fluid composition:
| Source Plate | Prefix |
|---|---|
| 384PP Plate | 384PP_AQ |
| 384PP Plus Plate | 384PP_Plus_AQ |
| 384LDV Plus Plate | 384LDV_AQ |
| Echo Qualified Reservoir | 6RES_AQ |
| Suffix | 384PP | 384PP Plus | 384LDV Plus | Reservoir |
|---|---|---|---|---|
_BP |
0–2% CMC | 0–5% CMC | N/A | N/A |
_SP |
5–50% CMC | 2.5–50% CMC | N/A | N/A |
_SPHigh |
200% CMC | N/A | N/A | N/A |
_GP |
N/A | 0–50% glycerol, 0–5% CMC | 0–50% glycerol | N/A |
_GPSA |
N/A | 0–50% glycerol, 5–14% CMC | N/A | N/A |
_GPSB |
N/A | 0–50% glycerol, 14–50% CMC | N/A | N/A |
_BP2 |
N/A | N/A | N/A | 0–30% glycerol, 0–2% CMC |
_GPSA2 |
N/A | N/A | N/A | 0–30% glycerol, 2–30% CMC |
_GPSB2 |
N/A | N/A | N/A | 0–30% glycerol, 30–50% CMC |
CMC = Critical Micelle Concentration (surfactant threshold). Example fluids: 384PP_AQ_BP = buffer with protein; 384PP_Plus_AQ_GP = buffer with glycerol and protein; 6RES_AQ_GPSA2 = buffer with 0–30% glycerol and 2.5–30% CMC surfactant.
Converting a reagent's concentration to %CMC: when the surfactant concentration is known in %w/v or mM rather than %CMC directly, use references/cmc-conversion.md — per-detergent lookup tables (Triton X-100, Tween 20, SDS, Brij 35, NP-40, Chaps, CTAB, Pluronic F-68) converting %CMC to %w/v and to mM. Find where the reagent's concentration falls in the detergent's row to read off %CMC, then use that value in the suffix table above.
Empirical dead/max-fill volumes and Echo insert type per plate are in the table above (Actual columns) — wicking can further cap max fill for high-CMC fluids in 384PP Plus (40 µL cap at 50–200% CMC) and 384LDV Plus (8 µL cap for 2 h at 50% CMC).
Pick list format
Standard header
Use this column order for import into Echo Cherry Pick:
Source Plate Type,Source Plate Barcode,Source Well,Transfer Volume,Destination Plate Type,Destination Plate Barcode,Destination Well
Source well selector notation
| Example | Meaning |
|---|---|
A1 |
A single source well. |
B1:B5 |
A contiguous range, position-paired 1:1 with a matching destination range (e.g. P2:P6). |
{A1:P1} |
A pooled region — any well in the braced range holds identical content; transfer from one. |
{A1;A2;A7;A8} |
A discrete pooled set — semicolon-separated, non-contiguous wells with identical content. |
{A1;A2;B6:B16} |
Discrete wells and a range can be mixed inside one pooled selector. |
{C1:C6;K12:K18} |
Multiple pooled ranges in one selector. |
The four canonical pick list flavors (Echo Cherry Pick sample files)
Each flavor has its own column set — not a subset of one universal schema. Sample files: references/384-384_NextAvailableWell.csv, references/384-384_Explicit.csv, references/384_Controls.csv, references/ComplexPickList.csv.
- NextAvailableWell —
Source Plate Barcode,Source Wellonly. No transfer volume, destination, or plate type per row — destination is "next available well," with plate-copy/replicate count and transfer volume set in protocol settings. - Explicit —
Source Plate Barcode,Source Well,Destination Plate Barcode,Destination Well,Transfer Volume. Explicit per-row destination and volume; plate copies/replicates must be 1. No plate type column — calibration is set once in protocol settings, not per row. - Controls —
Source Plate Barcode,Source Well,Destination Well,Transfer Volume. No destination plate barcode (implicitly the same destination plate as the Explicit/NextAvailableWell list it's paired with) and no plate type; scoped to controls, combinable with either of the above. - ComplexPickList —
Source Plate Barcode,Source Plate Type,Source Well,Destination Plate,Destination Well,Transfer Volume,Description. Full form: source barcode + calibration type, a (possibly pooled) source well selector, one destination plate/well, and transfer volume (Descriptionis annotation in the sample only, not a real import field). This is the flavor the Standard header above is modeled on.
Every one of these four samples includes Source Plate Barcode, which is why the Standard header requires it too — it's not needed for a single-source-plate run, but becomes required once a method pools reagents across multiple physical source plates.
Designing a method — workflow
- Identify each reagent's fluid composition (protein? surfactant/CMC %? glycerol %?) and pick the calibration suffix from the table above.
- Pick the physical source plate (prefix) — default to 384PP Plus unless dead-volume economy (384LDV Plus) or reservoir-scale bulk reagent (Echo Qualified Reservoir) is needed.
- Size source wells against the plate's actual (not stated) working volume, plus the instrument's per-well dead volume.
- Confirm every required transfer falls in 25 nL–5 µL (well-to-well) or up to 45 µL (well-to-many, i.e. pooled source); split across additional pooled source wells if not.