Hach 21680-42 DEHA Reagent 2 Solution
Overview
Hach 21680-42 is a genuine Hach DEHA Reagent 2 Solution, supplied in a 100 mL bottle, formulated as the companion reagent to DEHA Reagent 1 for the determination of oxygen scavengers in boiler feedwater and process water systems by the iron reduction method. Used together under Hach Method 8140, the Hach 21680-42 solution enables plant chemists to accurately quantify diethylhydroxylamine (DEHA), carbohydrazide, hydroquinone, iso-ascorbic acid and methylethylketoxime concentrations, providing the analytical confirmation needed to verify correct oxygen scavenger dosing across steam and boiler water treatment programs.
As the official authorized partner and exclusive regional representative for Hach, Seven Star LLC proudly supplies genuine Hach 21680-42 DEHA Reagent 2 Solution to industrial plants throughout Oman and the GCC. Every bottle shipped from our Muscat-based facility is sourced directly through Hach’s authorized distribution channel, ensuring authentic reagent chemistry, correct shelf-life dating and full compatibility with existing Hach spectrophotometers and DR900-series colorimeters already deployed across regional power generation and process water laboratories.
Operating Principle
The Hach 21680-42 DEHA Reagent 2 is the ferric iron source in the two-part colorimetric reaction specified in Hach Method 8140. Dosed at 0.5 mL into the sample bottle and the reagent blank after the DEHA Reagent 1 powder pillow has been added, it supplies the ferric iron that the oxygen scavenger in the sample reduces to the ferrous state, in an amount equivalent to the scavenger concentration. The chromogenic chemistry of DEHA Reagent 1 then forms a purple complex with that ferrous ion, and the connected Hach spectrophotometer or colorimeter converts the resulting colour intensity into a quantitative reading across the method’s calibrated working range.
Because the reagent solution is factory formulated to a fixed concentration and dosing volume, results obtained using DEHA Reagent 2 alongside DEHA Reagent 1 provide plant chemists with consistent, repeatable analytical accuracy test after test. This reliability allows boiler water treatment programs to confidently verify oxygen scavenger residuals remain within the target dosing range needed to prevent dissolved oxygen corrosion in feedwater heaters, economizers, deaerators and boiler tubes, protecting high-value capital equipment from premature failure.
Engineering Design of the Hach 21680-42
The reagent is supplied as a ready-to-use liquid solution in a 100 mL amber or clear glass bottle designed for laboratory bench use, with a dropper or metered dispensing cap that delivers a consistent, repeatable dose volume for each test performed. This liquid format complements the powder pillow presentation of DEHA Reagent 1, together forming the complete two-reagent kit required to execute the Method 8140 procedure from start to finish.
The 100 mL bottle size is calibrated to support a substantial number of individual test doses before requiring replacement, matching typical laboratory consumption rates in power plant and process water testing programs. The solution is compatible with Hach DR-series spectrophotometers and portable colorimeters commonly deployed in boiler chemistry laboratories, integrating directly into existing Hach-based water quality testing workflows without requiring additional calibration equipment or method adaptation.
Key Features
The Hach 21680-42 DEHA Reagent 2 Solution delivers dependable performance around the following capabilities:
- Completes the two-part Hach Method 8140 colorimetric procedure for oxygen scavenger determination.
- Supplies the ferric iron that the oxygen scavenger reduces, driving the Method 8140 colour reaction.
- Supplied as a ready-to-use 100 mL liquid solution with metered dispensing for consistent dosing.
- Companion reagent to DEHA Reagent 1, together forming a complete testing kit for DEHA analysis.
- Compatible with Hach DR-series spectrophotometers and portable colorimeters for lab or field testing.
- Genuine Hach chemistry ensures repeatable, laboratory-grade analytical results across testing programs.
- Supports oxygen scavenger verification across carbohydrazide, hydroquinone and DEHA dosing regimes.
- Enables proactive boiler water treatment monitoring to prevent dissolved oxygen corrosion damage.
Dosing, Yield and Laboratory Handling
Chemically, the role of the Hach 21680-42 solution in Method 8140 is to supply the ferric iron that the oxygen scavenger reduces: DEHA, carbohydrazide, hydroquinone, iso-ascorbic acid or methylethylketoxime in the sample converts that ferric iron to the ferrous state, and the ferrous ion produced is what the accompanying powder pillow chemistry renders as a purple colour for photometric measurement. The published procedure calls for 0.5 mL of the solution to be added to the prepared 25 mL sample bottle and to the reagent blank, so a 100 mL bottle yields roughly 200 individual doses, or in the region of 100 paired sample-and-blank determinations before replacement is needed. Laboratories running high test volumes can specify the same chemistry in a 500 mL presentation (Hach 21680-49), or order both halves of the kit together as the Hach Oxygen Scavenger Reagent Set.
Because the reagent is a metered liquid rather than a sealed single-dose pillow, handling discipline matters more here than on the powder side of the kit. A dedicated dispenser or dropper should be used so that the bottle neck never contacts a reacted sample, the cap should be replaced immediately to limit evaporation and air oxidation of the ferric solution, and the bottle should be stored upright, tightly closed and away from direct sunlight and heat — a relevant point for laboratories in Oman where bench and store temperatures can swing widely. Seven Star LLC ships every bottle of Hach 21680-42 with its batch and expiry information intact, and the current safety data sheet is available on request for plant COSHH files before the reagent enters the laboratory.
Industrial Applications
The Hach 21680-42 DEHA Reagent 2 is used extensively in power generation plant chemistry laboratories, industrial steam boiler operations, and process water treatment facilities where oxygen scavenger dosing must be verified to protect high-pressure boiler and feedwater systems from corrosion damage. In Oman’s power generation and desalination sector, as well as petrochemical steam systems across Muscat, Sohar and Salalah, plant chemists rely on DEHA Reagent 2 in combination with Reagent 1 to confirm oxygen scavenger residuals remain within specification across daily and shift-based monitoring routines.
As the officially authorized partner for Hach in Oman and the GCC, Seven Star LLC distributes genuine 21680-42 reagent bottles to power plant laboratories, water treatment operators and industrial testing contractors throughout the region, backed by regional warehouse stock and manufacturer-authenticated supply with confirmed shelf-life dating. Facilities across Sohar’s industrial port zone and Salalah’s free trade zone depend on Seven Star LLC for genuine Hach reagent chemistry with full batch traceability.
Technical Specifications
| Parameter | Specification |
|---|---|
| Model | Hach 21680-42 |
| Description | DEHA Reagent 2 Solution |
| Method | Hach Method 8140, Iron Reduction |
| Bottle Size | 100 mL |
| Companion Reagent | DEHA Reagent 1 (Hach 21679-69) |
| Application | Boiler feedwater oxygen scavenger determination |
| Dose Volume | 0.5 mL per 25 mL sample bottle and per blank |
| Approximate Yield | ~200 doses per 100 mL bottle (~100 paired tests) |
| Function in Method | Ferric iron source reduced by the oxygen scavenger |
| Measured Compounds | DEHA, carbohydrazide, hydroquinone, iso-ascorbic acid, methylethylketoxime |
| Reaction Conditions | 10 minutes in the dark (2 minutes for hydroquinone), 25 ± 3 °C |
| Alternative Pack Size | 500 mL (Hach 21680-49) |
| Storage | Upright, tightly closed, away from direct sunlight and heat |
| Compatible Instruments | Hach DR-series spectrophotometers, colorimeters |
Request a Quote for Hach 21680-42 DEHA Reagent 2 Solution
Seven Star LLC invites plant chemists and procurement teams across Oman and the GCC to submit a formal RFQ for the Hach 21680-42 DEHA Reagent 2 Solution. As the authorized partner for Hach in Oman and the GCC, we maintain regional warehouse stock for rapid dispatch, provide technical datasheets and method sheets on request, and offer direct access to our water analytics division for testing program support. Contact Seven Star LLC today to secure genuine Hach 21680-42 reagent with full manufacturer traceability and regional warranty backing.
Related Products
Hach is a global leader in water quality analysis and laboratory instrumentation, providing reliable solutions for monitoring and improving water and wastewater processes. Founded in 1947, Hach has built a strong reputation for accuracy, innovation, and ease of use in analytical measurement.
Its comprehensive product range includes spectrophotometers, turbidity meters, pH and conductivity sensors, online analyzers, and reagent kits designed for precise measurement and regulatory compliance. Hach instruments are widely used in municipal water treatment, environmental monitoring, industrial process control, and laboratory applications.
Seven Star LLC supplies authentic Hach analytical instruments and sensors to clients across the Middle East, offering dependable water analysis solutions backed by proven global expertise and local technical support.
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