NEW – Hanna Bench Meters

Precision just became more accessible!

NEW – Hanna HI-2600 bench meters

Innovation simplified

The new series of HI-2600 bench meters are innovation simplified offering an entry level instrument packed full of features & technology at a very competitive price without compromising on quality.

Each meter is supplied as standard with an appropriate digital smart probe with an integrated temperature sensor, USB-C cable, Power Adapter, Electrode Holder, Quality Certificates and a starter calibration pack.

Features and Benefits

• Seven models in the range: one multi-parameter and six single-parameter versions.
• Single-parameter models for pH, EC, and Dissolved Oxygen.
• Multi-parameter model measures pH, ORP, EC, and DO with smart probe recognition.
• Large 5.5″ display
• Smart electrode technology means elimination of signal drift.
• Electrode comes with unique serial ID for traceability and predictive maintenance messages
• Data from last calibration stored on the electrode

• Two Operating Modes depending on model.  Can be used in Standard or Basic operating modes. Standard Mode enables all features while Basic Mode reduces features—ideal for routine measurements by displaying a simplifed screen and features.
• Capacitive Touch Keypad. Sensitive capacitive touch buttons for accurate keystrokes for navigating menus and screens. Since they are part of the screen, the buttons can never get clogged with sample residue.
• Small Footprint
• Data logging depending on model
• USB-C Port for Data Transfer depending on model

Many more features.  Download the flyer below and select your model!

Hanna Instruments is a world leader in pH and titration science helping professionals with their everyday testing needs.

Download the flyer

For full Brochure with specs download here

WTW SenTix 41 pH probe for freshwater.

pH electrodes with gel electrolyte and built-in temperature sensor are ideal for portable measurement but also for routine measurement in the lab.

PRODUCT FEATURES

• Standard electrodes with gel electrolyte and built-in temperature sensor for pH measurement in lab and field.

• Maintenance-free gel reference system over the entire product life

• Automatic temperature compensation

• Robust plastic shaft

Overview

WTW SenTix 41 pH probe for freshwater.

pH electrodes with gel electrolyte and built-in temperature sensor are ideal for portable measurement but also for routine measurement in the lab.

PRODUCT FEATURES

• Standard electrodes with gel electrolyte and built-in temperature sensor for pH measurement in lab and field.

• Maintenance-free gel reference system over the entire product life

• Automatic temperature compensation

• Robust plastic shaft

SenTix®41: 1 m fixed cable with DIN plug and 4 mm banana plug SKU: 103635

The new optimized membrane glass guarantees quick measurement even at low temperatures.

The silver ion-free reference electrolyte prevents interference by precipitated silver (self-cleaning).

SenTix® PLUS electrodes with Gel electrolyte and a plastic body are robust and shockproof. The membrane glass is optimally safe-guarded by a protective shield.

SenTix® H and HW electrodes: electrolyte flow speed can be adjusted for optimal use.

The easy to use fill-hole cover prevents electrolyte from leaking out during storage.

Waterproof DIN or BNC plugs, either as a plug head system or with fixed cables, are available.

SenTix® PLUS electrodes with liquid electrolyte – the capillary effect of the platinum wire guarantees constant outflow and prevents contamination by precipitates or dirt even during changes in temperature; with new membrane glass for an even quicker response.

Measures also the temperature. For more information and to place an order click here.

WTW inoLab® pH 7310P BNC

 

The WTW inoLab® pH 7310 Benchtop Meter with back-lit graphic display is the right meter for precision measurements of pH and ORP potentials, as well as automatic documentation according to GLP/AQA in quality labs in all industries. All measured values are transmitted with the current date, time, ID number and sensor serial number (can be entered manually).

 

Product Features

·         precise pH meter with documentation function to use in quality assurance, pharmaceutical industry and everywhere GLP-supported documentation is required

·         Repeatable measuring results by automatic recognition of stable values

·         Monitoring of the optimum measuring range via CMC function

·         Secure and convenient operation via text menus in a bright graphic display  

Documentation via built-in printer

The inoLab® 7310P option offers a built-in printer for printing of measurement and calibration results on high quality paper with a readability of up to 7 years.

pH measurement

Data optimization is achieved with the new CMC function that monitors the calibration range and indicates if the measurement range is between calibration points. All meters are available in application sets including sensors, electrode stand and power supply.

 

 

https://www.totallabsupplies.co.uk/wtw-inolab-ph-7310p-bnc/

Currently available from stock, ref 1AA320P (With printer option).  Ask for a quote today.

On this day

On 8th January 1868, Søren Peder Lauritz Sørensen was born in Havrebjerg, Denmark.  He died on 12th February 1939.  He was a Danish chemist famous for the introduction of the concept of pH, a scale for measuring acidity and basicity.

From 1901 to 1938 he was head of the prestigious Carlsberg Laboratory, Copenhagen. While working there he studied the effect of ion concentration on proteins, and because the concentration of hydrogen ions was particularly important, he introduced the pH-scale as a simple way of expressing it in 1909.

The article in which he introduced the scale (using the notation pH), described two new methods for measuring acidity. The first method was based on electrodes, while the second involved comparing the colours of samples and a preselected set of indicators.

pH is a measure of the acidity or basicity of an aqueous solution. Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline. Pure water has a pH very close to 7.

For more information visit:-

http://en.wikipedia.org/wiki/PH

http://www.encyclopedia.com/topic/Soren_Peter_Lauritz_Sorensen.aspx

pH Indicators

A pH indicator is a colour changing (or halochromic) chemical compound that is added in small amounts to a solution so that the pH (acidity or basicity) of the solution can be determined visually.

A pH indicator is a chemical detector for hydronium ions (H3O+) or hydrogen ions (H+).  Normally, the indicator causes the colour of the solution to change depending on the pH.

pH (potential of hydrogen) is a scale of acidity from 0 to 14. It tells how acidic or alkaline a substance is. More acidic solutions have lower pH. More alkaline solutions have higher pH. Substances which are not acidic or alkaline (neutral) usually have a pH of 7. Acids have a pH less than 7. Alkalis have a pH greater than 7.

pH indicator solutions are themselves weak acids or bases.  As one chemical is added it changes the arrangement of the electrons in the molecule causing it to absorb different wavelengths of light and therefore appear different in colour.

Different chemicals can be used for different pH ranges as shown in the diagram below.

 

pH indicators are frequently employed in titrations in analytical chemistry and biology to determine the extent of a chemical reaction. Because of the subjective choice (determination) of colour, pH indicators are susceptible to imprecise readings. For applications requiring precise measurement of pH, a pH meter is frequently used.

Many plants or plant parts contain chemicals from the naturally-coloured anthocyanin family of compounds. They are red in acidic solutions and blue in basic. Anthocyanins can be extracted with water or other solvents from a multitude of coloured plants or plant parts, including from leaves (red cabbage); flowers (geranium, poppy, or rose petals); berries (blueberries, blackcurrant); and stems (rhubarb). Extracting anthocyanins from household plants, especially red cabbage, to form a crude pH indicator is a popular introductory chemistry demonstration.

For more information visit:-

http://en.wikipedia.org/wiki/PH_indicators

http://www.compoundchem.com/2014/04/04/the-colours-chemistry-of-ph-indicators/

 

Measuring Conductivity

The conductivity (or specific conductance) of an electrolyte solution is a measure of its ability to conduct electricity. The SI unit of conductivity is siemens per meter (S/m).

Conductivity measurements are used routinely in many industrial and environmental applications as a fast, inexpensive and reliable way of measuring the ionic content in a solution. For example, the measurement of product conductivity is a typical way to monitor and continuously trend the performance of water purification systems.

In many cases, conductivity is linked directly to the total dissolved solids (T.D.S.). High quality deionised water has a conductivity of about 5.5 μS/m, typical drinking water in the range of 5-50 mS/m, while sea water about 5 S/m (i.e., sea water's conductivity is one million times higher than that of deionised water)

Conductivity Meters - Two electrodes with an applied AC voltage are placed in the solution. This creates a current dependent upon the conductive nature of the solution. The meter reads this current and displays in either conductivity (EC) or ppm (TDS).

Our two part guide will help you to measure conductivity accurately.  The guides answer the 7 most asked questions regarding conductivity and the second part is a comprehensive guide on theory and measurement.

Just click on the links below to download your copies.

Part 1 - http://www.prlabs.co.uk/news/article.php?Id=232
Part 2 - http://www.prlabs.co.uk/news/article.php?Id=233

Care and Storage of pH Electrodes

The life of a pH electrode is not infinite. A number of factors affect the life span of a pH electrode. The higher the temperature that the electrode is used at, the more extreme the pH, how often the bulb dries out and needs to be rehydrated, how roughly it is used; all these factors and more shorten the life span of an electrode. An electrode that is well maintained and cared for can last up to 2 years, one that is not well maintained will not last as long, and one that is well maintained will not last significantly longer.

 

Storage of the pH electrode when not in use.

The pH electrode bulb needs to be moist at all times. When you are done with the electrode pour electrode storage solution into the cap that came with the electrode and put the cap over the bulb of the electrode. Keep the cap on until next use. If the electrode is being stored for a long time you may want to check the cap to be sure the storage solution is still in the cap and keeping the bulb moist. DO NOT STORE THE pH ELECTRODE IN DISTILLED WATER. Storing the pH electrode in distilled water will shorten the life of your pH electrode.

 

If you do not have electrode storage solution use pH 4 buffer solution. If you have neither electrode storage solution or pH 4 buffer solution you can use pH 7 buffer solution for a short time.

 

Rinsing the pH electrode between measurements.

You should rinse your pH electrode between measurements. This can be done with distilled water or rinsing with a sample of the next solution to be measured. Using both distilled water and then a sample of the next solution is also a good way to rinse the pH electrode between measurements.

 

pH electrode fill hole

Some pH electrodes have a fill hole for refreshing the electrolyte in the pH electrode; other pH electrodes do not have a fill hole. If your pH electrode has a fill hole the fill hole cap should be removed during calibration and use. This allows for the correct amount of reference electrolyte to flow into the sample. Replace the fill hole cap when done with the electrode at the end of the day

 

If bulb dries out, soak electrode bulb in pH 7

pH electrode bulbs should be keep moist at all times. When not in use the pH electrode bulb should be keep moist by pouring electrode storage solution in the cap provided. If the pH electrode bulb does dry out, soak it in pH 7 buffer for a couple of hours before calibrating or taking measurements.

 

Do not wipe the pH electrode with a cloth or any other type of material.

When you are done with the pH meter rinse off the electrode with distilled water, put storage solution in the cap, and put the cap on the end of the pH electrode as described above. If the electrode is wet do not dry it off, let the distilled water evaporate by itself.

 

Cleaning the pH electrode

The pH electrode needs to be cleaned in order to prevent build up of material on the surface of the glass bulb. How often it needs to be cleaned depends upon frequency of use and the material being tested. An electrode used on dark coloured and viscous material usually needs to be cleaned more often than an electrode used on clear thin material.  Material building up on the glass bulb of the electrode will cause the calibration of the electrode to be inaccurate and any subsequent reading to be inaccurate. Follow the instructions supplied with the electrode cleaning solution when cleaning the electrode bulb.

 

P&R Labpak supply a wide range of electrode storage solutions, buffers and other associated accessories from all major manufacturers including Hanna Instruments, Mettler Toledo, Sentek, Jenway, Schott, WTW etc...

 

Visit www.prlabs.co.uk or call us on 0870 034 2055.

pH Measurement theory and Electrodes

pH Measurement

The measurement of pH using a pH Electrode is an age old method that centres around
the perception of a substance as acidic or alkaline and is dependent on the concentration
of the hydrogen Ion (H+) within the substance.

The use of a pH electrode allows this measurement to be expressed in a meaningful way.

Derived from the Sorensen Equation the pH value is defined as a negative logarithm of the H+ concentration in a given solution.

A high H+ Concentration equals: 1mol/L = 10o pH = 0 (ACIDIC)

A low H+ Concentration equals: 10-14 mol/L pH=14 (ALKALINE)

It is therefore simple to measure the pH of a substance and compare it with other substances. pH 0 is extremely acidic, pH 14 is extremely alkaline and pH 7 neutral.

Measuring pH Values

Measuring the pH of a substance requires the use of a pH Electrode and a Reference Electrode. The pH Glass at the end of the electrode acts as the sensing part of the circuit.

The second part of the circuit is the reference electrode. This is a stable point that has a defined potential and is independent of the solution to be measured. The reference electrode fig is made up of a reference element that is commonly a Silver/Silver Chloride wire encased in a known electrolyte. The reference electrode then has a junction, which is the contact between the stable internal reference electrode and the solution to be measured. This is commonly a porous ceramic pin.

The evolution of pH electrodes came with the joining of the two separate electrodes to produce the COMBINATION pH ELECTRODE. The formation of the combination electrode can be seen below. The formation of the combination electrode still has the pH Glass membrane acting in the same way. The reference electrode is continually encased around the pH electrode. As the pH Glass comes into contact with an aqueous substance to measure, a gel layer forms on the membrane. This also happens on the inside of the glass layer. The pH value of the aqueous solution will either force Hydrogen Ions out of the Gel layer or into this layer. The Internal buffer in the glass electrode has a constant pH value and this keeps the potential at the inner surface of the membrane constant. The membrane potential is therefore the difference between the inner and outer charge. If you then factor in the reference electrode with its stable potential you have a combination pH electrode that encapsulates the measuring electrode and reference electrode.

P&R Labpak are able to offer a huge range of electrodes and through it’s electrode supplier Sentek can offer their equivalents which are less expensive and yet are the same or better quality.  Contact us on 0870 034 2055 or e-mail us at sales@prlabs.co.uk with your electrode enquiries.

 

How the pH Electrode Works

As the pH Glass comes into contact with an aqueous substance to measure, a gel layer forms on the membrane.
This also happens on the inside of the glass layer.

The pH value of the aqueous solution will either force Hydrogen Ions out of the Gel layer or into this layer.
The Internal buffer in the glass electrode has a constant pH value and this keeps the potential at the inner
surface of the membrane constant.

The membrane potential is therefore the difference between the inner and outer charge.
If you then factor in the reference electrode with its stable potential you have a combination
pH electrode that encapsulates the measuring electrode and reference electrode.

Visit www.prlabs.co.uk for more information or to contact us.  Check out our news pages for special offers – www.prlabs.co.uk/news