Measure higher COD loads with the correct small-volume method.
Keep high-strength sample work on the correct analytical path with HI93754C-25 high-range dichromate reagent vials. One pack supplies 25 pre-dosed vials for COD HR over 0–15000 mg/L as O₂. The method uses a 0.2 mL sample aliquot, so accurate small-volume delivery is central to the workflow; transferring a low- or medium-range 2 mL instruction to this formulation would be incorrect.
Official Hanna HI93754C-25 packaging reference. Printed lot and expiration details are illustrative, not the supplied stock’s lot or expiry.
Match the refill to the complete method
Select HR when the expected oxygen demand and your validated method require the 0–15000 mg/L as O₂ range. This is the high-range dichromate formulation, not a universal EPA-approved product. Manufacturer discussion of standard EPA/ISO methods up to 1500 mg/L does not certify this high-range application for every permit or reporting program.
A refill for a complete digestion workflow
The pack contains 25 ready-to-use vials of HI93754C-0 reagent, not a photometer, reactor or starter kit. Pre-measured chemistry reduces the need to prepare bulk COD reagents or clean reaction glassware between determinations. Select the COD HR program on the compatible instrument and retain the exact method instructions with your laboratory SOP. Do not infer automatic barcode recognition from this catalog number.
Plan the blank before counting samples
A complete preparation starts with separate reagent vials for sample and blank: add 0.2 mL sample to one and 0.2 mL deionized water to the other, using the same reagent lot. The nominal 25-vial pack is not a promise of 25 reportable samples. The bench instrument manuals plan 24 samples with one blank; additional blanks, quality-control checks and repeats consume more vials. Follow the exact instrument method and your laboratory quality plan rather than assuming one blank can serve every batch.
Allow time for digestion and controlled cooling
All three documented instrument workflows require heated digestion at 150 °C for 120 minutes, followed by the prescribed cooling and mixing sequence. Have the separately supplied, existing HI839800-01 reactor available; the photometer does not replace the digestion block. Use the proper cooling rack, handle hot acid vials with the prescribed protective equipment, and never place hot vials in the photometer adapter. An oven or microwave is not a substitute for the specified reactor.
Check equipment and matrix together
Exact reagent-to-method compatibility is documented for HI97106, HI83314 and HI83399. Follow each model’s adapter installation and vial-handling instructions; generic holder fit is not established. Provide deionized water, an accurate 200 µL pipette with suitable tips, a cooling rack and SDS-prescribed PPE separately. A safety shield is strongly recommended. Homogenize samples containing settleable solids as the method directs. The instrument methods flag chloride above 20000 mg/L; assess dilution and the reporting calculation under the exact method rather than treating the reagent as immune to matrix interference.
Read the method reference in its reporting context
Hanna describes HI93754C-25 as an adaptation of the dichromate method for high-range COD. The instrument manuals also use EPA 410.4 adaptation language, but a reference heading is not universal regulatory approval of this high-range reagent or measurement. Confirm high-range applicability, any required dilution, quality controls and reporting acceptance with the governing method or permit authority.
Keep traceability and hazardous-waste handling visible
Store unused vials in their original packaging in a cool, dark place and follow the current label and SDS. Hanna identifies the lot and expiration date on the box and supplies a certificate of quality; no fixed remaining shelf life or supplied-lot expiry is promised here. These acid/dichromate reagents contain mercury(II) sulfate. Review the exact US component SDS before handling, use suitable protection and ventilation, and route used vials through regulated hazardous-waste handling with an authorized provider. Do not pour spent reagent down a drain. Dangerous Goods shipping is ground-only; this page does not authorize air transport.
Frequently Asked Questions
What exactly does one HI93754C-25 order contain?
One sellable pack of 25 pre-dosed high range COD reagent vials. It is a reagent refill only. The photometer, HI839800-01 reactor, deionized water, pipettes, tips, cooling rack, safety shield and protective equipment are not supplied by this listing. The catalog suffix describes the vial pack, not 25 guaranteed reportable sample results.
Which range and reporting units should I use?
Use the COD HR method over 0–15000 mg/L as O₂. Record results as chemical oxygen demand expressed as O₂, not as dissolved oxygen or elemental oxygen concentration. Choose the formulation and photometer program to match the expected sample range; another COD reagent is not an interchangeable refill just because its pack also has 25 vials.
Will these work with my Hanna instrument?
The exact reagent code is documented in the COD HR methods for HI97106, HI83314 and HI83399. Follow the adapter and vial-positioning instructions for your exact model, including the HI97106 COD adapter requirement. No physical vial diameter or universal holder compatibility is claimed. The instrument manuals in the document tab are method references, not standalone reagent manuals.
Why are 25 vials not necessarily 25 samples?
A required reagent blank uses one vial. The bench instrument manuals plan 24 sample tests from a 25-vial pack with one blank, while additional blanks, repeats and QC consume further vials. Blank and samples must use the same reagent lot. Although the manuals describe conditional blank reuse, follow the exact method and QC schedule and run a blank for each measurement set for improved accuracy; no universal reuse promise is made.
How much sample goes into a vial?
Add 0.2 mL sample to the sample reagent vial and 0.2 mL deionized water to a separate blank reagent vial, following the exact instrument method. This is 200 µL, not 2 mL. Use a calibrated small-volume pipette and suitable tips; do not carry LR/MR aliquot instructions into HR work.
Do I need a separate reactor?
Yes. The documented COD methods require digestion at 150 °C for 120 minutes in a suitable reactor, followed by the specified cooling sequence before zeroing and reading. Provide the HI839800-01 reactor separately. Neither the photometer nor this reagent pack performs digestion on its own. Follow the hot-vial precautions, cooling-rack procedure and safety-shield guidance in the method.
Does the method name guarantee regulatory acceptance?
No. This is a high-range dichromate adaptation, not a universally EPA-approved product. Standard-method references and the instrument manual’s EPA-adaptation heading do not establish acceptance of a 0–15000 mg/L result in every reporting program. Verify the applicable method range, dilution and QC requirements before reporting.
How should I store, ship and dispose of the vials?
Keep unused vials in their packaging in a cool, dark place and observe the supplied lot/expiry label and current HI93754C-0 US SDS. Shipping is Dangerous Goods, ground-only. The mixture includes acid, dichromate and mercury(II) sulfate; it is not harmless. Collect used vials as regulated hazardous waste and use an authorized waste provider under applicable requirements. Do not assume drain disposal or air shipping is permitted.
