Hanna Instruments

Scientific Equipment

Safety Data Sheets

SDS search & quick download

Free Delivery

Most of mainland GB for orders over £50. Other charges may apply - see more

Hanna Care

We take the long view, looking after existing customers as much as delighting new ones!

Certificates of Analysis

Download a copy of the certificate of analysis for your solution

HI-77400P pH Combination Buffer Solution Kit 4.01 & 7.01 5 x 5 20ml sachets

HI-77400P pH Combination Buffer Solution Kit 4.01 & 7.01 5 x 5 20ml sachets

Hanna HI-77400P pH Combination Buffer Solution Kit 4.01 & 7.01 5 x 5 20ml sachets

HI-77400P pH Combination Buffer Solution Kit 4.01 & 7.01 5 x 5 20ml sachets

Ideal for water purification plants, the food industry, aquatics, and Hydroponics
20ml individual sachets
In Stock
£16.30 (exc. VAT) £19.56 (inc. VAT)

Achieve accurate pH readings and check your meter and electrode is functioning correctly with Hanna buffer solutions. Available in convenient, ready-made pH values, Hanna has a certified value calibration solution with an accuracy of +/- 0.01pH @ 25◦C for all requirements. Available in 230ml, 500ml, 1 litre, and 1 gallon bottles, plus individually sealed foil sachets containing 20ml of ready-to-use solution.

*For even greater accuracy, scroll down to read Hanna’s Technical and Millesimal Buffer range explained.

HI-77400P pH Combination Buffer Solution Kit 4.01 & 7.01 5 x 5 20ml sachets information

Hanna's extended description

HI-77400P combination pH buffer kit with 5 x 20ml sachets of pH 4.01 and 5 x 20ml sachets of pH 7.01

The pH 4.01 & 7.01 buffer solutions in quick and easy to use 20ml sachets are the most popular buffers used before analysing samples. Ideal for those requiring an accurate acid or neutral reading, particularly suitable for those working in water purification plants, the food industry, aquatics, and Hydroponics, and in any environments where the pH is expected to be acid or neutral.

The single dose sachets are really handy with each sealed sachet holding just the right amount of solution. Each time a meter or electrode is calibrated using the Hanna sachets, it is like using a newly opened bottle of solution!

Benefits of individual packaging
  • Ideal for users who do not calibrate frequently
  • Ideal for field use due to portability
  • Every sachet is as fresh as the day it was packaged
  • Light block packaging prevents oxidation from UV light that could alter the buffer value.

Buffer solutions should be stored at 25°C, away from direct sunlight for accurate readings.

To correctly maintain your meter/electrode, we highly recommend use of a Hanna cleaning solution, as well as a buffer, for maximum performance every time. pH4, along with pH7, can also be used as an emergency storage solution.

Hanna buffer solutions are prepared, ready-to-use, according to precise formulas and standardised in accordance with the National Institute of Standards and Technology (NIST) to ensure quality and accuracy. All solutions show a batch number, an expiry date, and the correlation table between pH and temperature. A certificate of analysis is available on request. All bottled solutions are sealed with an air tight, tamper-proof seal to prevent any Carbon Dioxide from entering and causing a change in the pH buffer value.

  • Calibration only counts when using fresh solutions and properly cleaned electrodes every time.
  • Routine maintenance will ensure accurate readings while extending the life of the electrode.

Useful information:

Colour Coding for 1L and 1 gallon bottles:

    pH 4.01 - Red

    pH 7.01 - Green

    pH 10.01 – Violet

All calibration buffers are made to a premium quality, produced in accordance with ISO 3696/BS3978 standards using high purity salts, deionised water, certified weight-checked balances, and Class A glassware in a temperature controlled environment monitored with certified thermometers.

All bottles meet with FDA Standards (US Food and Drug Administration).

Browse the Hanna complete range of solutions

  • pH buffer solutions
  • Standard solutions for conductivity, Total Dissolved Solids (TDS), turbidity, salinity and Ion-Selective Electrode (ISE) calibration
  • Oxidation Reduction Potential (ORP) test and pre-treatment solutions
  • Reference fill solutions for refillable electrodes
  • General and specific cleaning solutions for electrodes
  • Solutions for electrode maintenance and storage
  • Solutions for sample preparation

Solutions are available in many sizes ranging from 20ml sachets for small users to 3.78L (1 gallon) containers for large quantity usage in laboratories.

For safety and traceability, all Hanna solutions are provided with a label showing the batch number and expiry date. A certificate of analysis is available on request in line with NIST standards.

Solutions are available in a variety of sizes. Check whether the solution you require is available in 1 gallon, 500ml, or 230ml bottles, or individual 20ml sachets.


Specifications list


pH Value@25°C 4.01 & 7.01
Size 20 mL
Package 10 sachets (5 each)
Certificate of Analysis No
Very reliable products

Handy sized box with good amount of both solutions - by Trusted Customer

Great service

Does exactly what it says - by Trusted Customer

Ideal product

Ideal for our engineer to do a self calibration on site. - by Trusted customer

Fantastic service, fast delivery and brilliant instruments

Fantastic, easy to use product making calibration a quick and easy process. - by Connor Izatt


Website was really easy to use. - by Andrew Finch

Questions & Answers

Got a question to ask? Use this form to submit your question.
Question will be displayed after moderation.
Name* Product Question*
No questions yet?
Don 't be shy, be the first to ask.