Interscience DiluFlow® Series Gravimetric Dilutors

Overview

The Interscience DiluFlow® Series represents a class of high-precision, gravimetric liquid handling systems engineered for microbiological and food safety laboratories requiring traceable, repeatable, and compliant sample dilution and dispensing. Unlike volumetric dilutors relying on fixed pipetting or peristaltic pumping, the DiluFlow® platform operates on a closed-loop gravimetric principle: real-time mass measurement via high-resolution load cells directly controls fluid delivery until the target weight—calculated from user-defined dilution ratios and initial sample mass—is achieved. This eliminates cumulative volumetric error from temperature-dependent liquid density, pipette tip variability, or tubing compliance. The system integrates seamlessly into GLP- and GMP-aligned workflows, supporting full traceability per ISO 7218 (microbiology — General requirements and guidance for microbiological examinations) and ISO 6887 (preparation of microbiological samples), including mandatory data integrity features such as operator identification, time-stamped event logging, and calibration history tracking.

Key Features

• Gravimetric Precision Architecture: Dual-range load cells (0.01 g readability up to 200 g; 0.1 g up to 7500 g max capacity) coupled with active drift compensation ensure consistent accuracy across wide dynamic ranges—critical for low-mass environmental swabs (≥0.5 g) and high-volume homogenate transfers (up to 375 g).
• Propeller-Driven Rapid Dispensing: Integrated motorized propeller agitator enables turbulent mixing during dilution, reducing settling artifacts and delivering 225 mL in under 6 seconds (Elite 5 kg model), significantly accelerating throughput in high-volume testing labs.
• GeckoGrip® Bag Handling System: Patented dry/wet-adhesive surface mimics gecko footpad microstructures—providing secure, non-slip bag retention without mechanical clamping or excessive force, minimizing operator fatigue and preserving bag integrity during repeated opening/closing cycles.
• Sub-30 cm Ergonomic Profile: Ultra-low footprint (<300 mm height) allows unobstructed operation inside biosafety cabinets (Class II A2/B2) and laminar flow hoods, eliminating neck strain and improving workflow integration.
• Intelligent LED Status Feedback: Three-color visual indicators (green ≥98%, orange ≥95%, red <95%) provide immediate, operator-independent verification of dilution accuracy post-cycle—reducing manual QC checks and enabling rapid root-cause assessment.
• Modular Pump Scalability: Base configuration supports one or two internal peristaltic pumps; optional expansion modules enable up to six synchronized pumps for parallel multi-dilution protocols or simultaneous dispensing into multiple tubes/vials.

Sample Compatibility & Compliance

The DiluFlow® Series accommodates standard Stomacher®-compatible stomacher bags (including 400 mL and Jumbo formats), sterile filtration bags, and custom pouches via its BagOpen® magnetic dual-point anchoring system—designed to stabilize the bag during weighing and prevent lateral movement-induced sensor interference. All models comply with ISO 7218:2018 Annex A (validation of dilution procedures) and ISO 6887-1:2017 (preparation of primary suspensions). Data output meets ALCOA+ principles (Attributable, Legible, Contemporaneous, Original, Accurate) and supports FDA 21 CFR Part 11 readiness when paired with validated LIMS interfaces. Full audit trails—including sample weight, final diluted mass, calculated dilution factor, diluent lot number, operator ID, and calibration status—are exportable in CSV or Excel-compatible formats for regulatory submission.

Software & Data Management

DiluFlow® instruments feature embedded firmware supporting 24 user-editable dilution programs, each configurable for sample mass, target dilution ratio, dispensing mode (Fast/Standard/Precise), and pump selection. Bidirectional LIMS connectivity is enabled via Ethernet or file-based exchange (USB drive, network share), transmitting structured metadata including sample ID, project name, operator credentials, date/time stamps, and instrument calibration due date. Optional monitoring software provides real-time graphical display of mass gain curves, deviation alerts, and batch-level statistical summaries (mean, SD, CV%). All data exports include digital signatures and immutable timestamps, satisfying ISO/IEC 17025:2017 clause 7.5.2 (control of records) and EU Annex 11 (computerized systems) requirements.

Applications

• Quantitative microbial enumeration (ISO 4833-1, ISO 11290-1) using serial decimal dilutions of food, environmental, or clinical specimens.
• Preparation of reference standards and calibration solutions in accredited reference labs (ISO/IEC 17025).
• High-throughput dilution for ELISA, PCR, and NGS library prep where volumetric uncertainty must be minimized.
• Homogenate transfer from stomacher bags to test tubes or filtration units under aseptic conditions.
• Automated dispensing into 9 mL universal tubes, Petri dishes, or membrane filtration cassettes without individual tube taring.

FAQ

What standards does the DiluFlow® Series comply with?
It meets ISO 7218:2018 (microbiological examination general requirements) and ISO 6887-1:2017 (preparation of primary suspensions), and supports compliance with ISO/IEC 17025, FDA 21 CFR Part 11, and EU Annex 11 through configurable audit trails and electronic signatures.

Can the DiluFlow® handle viscous or particulate-laden samples?
Yes—the propeller-assisted mixing and high-torque peristaltic pumps accommodate suspensions containing up to 15% w/v particulates (e.g., ground meat homogenates, soil extracts) without clogging, provided appropriate tubing and nozzle diameters are selected.

Is calibration traceable to national standards?
All load cells are factory-calibrated against certified reference masses traceable to COFRAC-accredited standards (France), with optional on-site recalibration services and documented certificate issuance per ISO/IEC 17025.

How is cross-contamination prevented between runs?
Each cycle includes automatic nozzle purging, programmable air-dry intervals, and physical isolation via the GeckoGrip® bag interface and retractable mechanical arm—validated over 1.3 million cycles with zero observed carryover in independent third-party testing (Interscience Technical Report TR-DIL-2023-04).

What is the expected service life and spare parts availability?
Designed for >100,000 operational cycles, the system carries a 1-year warranty and guaranteed spare parts availability for 10 years post-manufacture, including pump heads, tubing kits, load cell assemblies, and firmware update support.