Hach DR3900 Benchtop VIS Spectrophotometer

A guided benchtop spectrophotometer for routine water laboratories

The DR3900 is Hach’s benchtop visible-range spectrophotometer for drinking water, wastewater, food and beverage quality-control laboratories and power-plant chemistry. It covers 320 to 1100 nm, ships with more than 240 preprogrammed methods and 100 user program slots, and walks the operator through each test step by step. Hach describes the guidance as working like a GPS, so the operator gets accurate results each time.

When used with TNTplus vials the instrument takes ten readings and eliminates outliers, which makes scratched, flawed or dirty glassware a non-issue. RFID technology can update program calibration factors automatically when a TNTplus box is placed near the instrument, and optional RFID sample-ID tags support sample tracking.

Technical specifications

Methods and connectivity

Hach lists more than 35 TNTplus tests, many of them EPA compliant, including ammonia, COD, chlorine, chromium, iron, nitrate, nitrite, nitrogen, phosphorus and sulfate. The available-tests table in the datasheet covers a broad range of parameters; examples include free chlorine 0.02 to 10.0 mg/L, total chlorine 2 µg/L to 10.0 mg/L, COD 0.7 to 15,000 mg/L, total phosphorus 0.06 to 100.0 mg/L, nitrate nitrogen 0.01 to 35 mg/L, silica 3 µg/L to 100 mg/L, dissolved oxygen 6 µg/L to 40 mg/L, TOC 0.3 to 700 mg/L and suspended solids 5 to 750 mg/L.

Connectivity is by one Ethernet and three USB ports, and Hach states that the instrument is programmed to interface easily with its WIMS software or any LIMS. A Sipper Module is offered as an accessory for sample delivery.

Choosing between Hach spectrophotometers, and what to confirm

The DR3900 is the visible-range laboratory model. Hach’s DR6000 adds ultraviolet capability from 190 nm, while the DR1900 is the portable field instrument. If the work is chiefly colorimetric water testing with TNTplus and powder-pillow chemistry, the DR3900 is the general-purpose bench choice.

Before ordering, confirm which reagent chemistries and test methods your laboratory will run, the sample cells you already hold, whether an RFID sample-ID system is wanted, and the mains supply. Hach notes in the datasheet that the RFID features are currently available only in a list of countries printed there, so check availability for the Gulf region with the supplier, and note that specifications are subject to change without notice.

How the Hach DR3900 works

A lamp sends light through a filter-free optical system that picks one wavelength. The light passes through the sample cell, and a detector measures how much is absorbed. A reference beam corrects for lamp drift. The instrument turns the absorbance into a concentration with the stored method, and shows the result on the touch screen.

Where the DR3900 is used

• Drinking water laboratories
• Wastewater plant laboratories
• Food and beverage quality control
• Power-plant chemistry
• Industrial process water checks

Selection checklist for the DR3900

• Wavelength range of 320 to 1100 nm
• Tests needed, such as ammonia, COD or chlorine
• TNTplus vial use
• Cell types in the laboratory
• Sample tracking with RFID tags
• Data logging of 2000 values
• Network and USB needs
• Bench space for 4.2 kg

Installation, commissioning and maintenance notes for the DR3900

Place the instrument on a level bench away from direct sun, vibration and drafts. Connect the power supply and switch on. Let the lamp settle, then run the self-check. Keep the cell compartment clean and covered. Use clean, dry cells for every test.

Requesting a quotation for the Hach DR3900

Please send the tests wanted, the vials or reagents and the quantity. Seven Star LLC serves industrial customers in Oman and the GCC and replies with a quotation based on the information provided.

DR3900 wavelength range

The wavelength range is 320 to 1100 nm, with a bandwidth of 5 nm.

DR3900 wavelength accuracy

The accuracy is plus or minus 1.5 nm from 340 to 900 nm, with 1 nm resolution.

DR3900 photometric range

The photometric range is plus or minus 3.0 Abs from 340 to 900 nm.

DR3900 methods

More than 240 methods are preloaded, and 100 user program slots are free.

DR3900 display

The 7 inch TFT display has 800 by 480 pixels.

DR3900 data logger

The logger holds 2000 values with the result, date, time, sample ID and user ID.

DR3900 cell types

It takes 13 mm and 16 mm round cells, 1 cm and 5 cm rectangular cells, and 1 inch round and square cells.

DR3900 interfaces

It has two USB type A ports, one USB type B port, Ethernet and an RFID module.

DR3900 power and size

It runs on 110 to 240 V AC and weighs 4.2 kg.

Laboratory records for the DR3900

Record the method, the lot of reagent and the date of each test.

Choosing the right DR3900 accessories

Choose the cell holders and the RFID tags that match the vials and the sample plan of the laboratory.

Documents and quotation

The DR3900 datasheet is attached. For related Hach instruments, see the HQ4200 portable meter or the CL17sc chlorine analyzer, or browse Liquid Analytical Systems. Send the model number and the methods you need through the RFQ form.