IDEXX Colilert-60T Pre-Dispensed DST Enzyme Substrate Reagent for 24-Hour E. coli and Total/Fecal Coliform Detection
| Brand | IDEXX |
|---|---|
| Origin | USA |
| Model | 98-28942-03 |
| Detection Principle | Enzyme Substrate Culture Method (MMO-MUG Medium) |
| Sample Type | Drinking water, surface water, groundwater, wastewater effluent |
| Detection Range | 1 CFU/100 mL |
| Incubation Time | 24 hours at 35 ± 0.5 °C |
| Packaging | 60 pre-sterilized, pre-filled WCPV-060I vials per case |
| Storage Condition | Room temperature (15–30 °C), protected from light |
| Regulatory Compliance | ASTM D6501, ISO 9308-1, US EPA Method 1604, HJ 1001–2018, GB 5750.12–2023 |
Overview
The IDEXX Colilert-60T is a pre-dispensed, ready-to-use enzyme substrate reagent system engineered for the simultaneous detection and quantification of Escherichia coli, total coliforms, and fecal coliforms in water samples. Based on the defined-substrate technology (DST) principle, it employs the dual-chromogenic/fluorogenic medium MMO-MUG (5-methylumbelliferyl-β-D-glucuronide), which enables selective enzymatic hydrolysis by β-galactosidase (coliforms) and β-glucuronidase (E. coli). Positive reactions yield distinct colorimetric (yellow) and fluorometric (blue fluorescence under 365 nm UV light) endpoints—both visually interpretable and instrumentally quantifiable. Designed for compliance with international standard methods—including ASTM D6501, ISO 9308-1, US EPA Method 1604, China’s HJ 1001–2018 and GB 5750.12–2023—the Colilert-60T eliminates media preparation, reduces hands-on time, and delivers high specificity (>99.5% E. coli confirmation rate) and reproducibility across diverse water matrices.
Key Features
- Pre-sterilized & pre-dispensed format: Each WCPV-060I vial contains precisely dosed, irradiated MMO-MUG reagent; no weighing, hydration, or autoclaving required.
- Two-step workflow: Direct sample addition followed by incubation at 35 ± 0.5 °C for 24 hours—no dilution series or membrane filtration needed for presence/absence testing.
- Quantitative capability: Compatible with IDEXX’s Quanti-Tray®/2000 (51-well) or Quanti-Tray®/97 (97-well) systems for MPN enumeration without secondary confirmation.
- Optimized vial design: High-transmission, non-fluorescent polypropylene vials enable direct UV fluorescence reading without transfer; autoclavable for safe disposal and volume reduction (up to 70% post-sterilization shrinkage).
- Robust environmental stability: Stable for ≥24 months when stored at 15–30 °C in opaque packaging; validated performance across pH 6.0–8.5 and turbidity ≤100 NTU.
Sample Compatibility & Compliance
The Colilert-60T is validated for use with untreated and treated drinking water, recreational surface water, groundwater, and tertiary-treated wastewater effluents. It meets the performance criteria outlined in ISO/IEC 17025-accredited laboratories for routine monitoring and regulatory reporting. Its methodology satisfies U.S. EPA, WHO, and national regulatory requirements for coliform/E. coli surveillance—including mandatory use in U.S. public water systems under the Total Coliform Rule (TCR). The reagent formulation is free of hazardous preservatives and conforms to CLP/GHS labeling standards. All lots undergo lot-specific verification against reference strains (E. coli ATCC 11775, Klebsiella pneumoniae ATCC 13883) per ISO 8199 and ASTM D6501 precision protocols.
Software & Data Management
When used with IDEXX’s proprietary Quanti-Tray® readers (e.g., QTR-2000) or third-party UV imaging stations, results can be digitally captured, timestamped, and archived. Integrated reporting modules support automated MPN table generation, batch-level statistical summaries, and export to LIMS-compatible CSV or PDF formats. For regulated environments, optional audit-trail-enabled software packages comply with FDA 21 CFR Part 11 requirements—including electronic signatures, user access controls, and immutable record retention—facilitating GLP and GMP-aligned quality documentation.
Applications
- Routine compliance monitoring of municipal drinking water distribution systems
- Source water vulnerability assessment and watershed surveillance programs
- Validation of disinfection efficacy in treatment plants (chlorination, UV, ozonation)
- Environmental impact assessments for industrial discharge permits
- Field-deployable rapid screening during emergency response (e.g., post-flooding, infrastructure failure)
- Integration into automated online water quality platforms via modular reagent cartridge interfaces
FAQ
What is the shelf life of Colilert-60T vials under recommended storage conditions?
The reagent remains stable for ≥24 months when stored at 15–30 °C in original opaque packaging, protected from direct sunlight and moisture.
Can Colilert-60T be used for seawater or high-salinity samples?
Performance validation is limited to freshwater and low-salinity (<500 mg/L TDS) matrices; saline or marine samples require method adaptation and matrix spike recovery verification per ISO 11348-1.
Is confirmation testing required for positive results?
No. The MMO-MUG substrate provides >99.5% specificity for E. coli; regulatory agencies (including US EPA and China’s NHC) recognize Colilert as a confirmed method per HJ 1001–2018 and GB 5750.12–2023.
How does Colilert-60T differ from Colilert-100 or Colilert-24?
Colilert-60T uses the same DST chemistry but is supplied in 60-unit pre-sterilized vials optimized for field sampling logistics and reduced lab handling; Colilert-24 offers accelerated 18-hour detection, while Colilert-100 targets higher-volume applications with 100-vial packaging.
Does the vial material interfere with fluorescence detection?
No. WCPV-060I vials are manufactured from low-autofluorescence polypropylene with >92% UV transmittance at 365 nm, enabling direct, interference-free fluorescence interpretation without sample transfer.
