Hach have a wide variety of sample cells for use in their colorimeters and spectrophotometers. The correct type of sample cell that is required for every method programme with each compatible instrument will be detailed at the start of the method sheet. Here, any adapters that may be required along with any extra equipment needed to perform the test will also be listed. This is the typical format you will see:
Hach use a range of descriptions and terminology when describing their sample cells and here we explain what these mean and the implications to your testing:
The sample cells can be provided as a ‘matched’ pair. This means that they have been tested to ensure there are no inconsistencies in the way light passes through between each cell. This testing occurs at 423nm and 589nm wavelength and only one face is ‘matched’, so cells must be used in the correct orientation. Matching eliminates error in measurements between the blank cell and the sample being analysed. Because of this, matched sample cells are more expensive to purchase than unmatched sample cells.
Different capacities (such as 10ml)
Sample cells may be listed with different capacities. You would have to make sure the capacities match to that of your reagent being used, for example a 10ml powder pillow would be used with a 10ml sample cell. Some sample cells with a larger capacity such as 25ml will also be marked at other intervals like 10ml so can be used for both tests. The 10ml tests are a newer addition to the range and require less sample to be analysed.
Sample cells used in colorimeters and spectrophotometers are typically round or square but can also come in other shapes such as rectangular. Round and square sample cells of the same size are not interchangeable and the correct shape listed in your method sheet must be selected (The path length of each is slightly different as a 1 inch square cell has a path length of approximately 8% longer than the round). Some cells are shaped to have multiple path lengths and so must be used in the correct orientation specified for your test method.
The most common sizes of sample cells are 1 inch (~25mm) and 1cm and to switch from 1 inch to 1cm you may have to use an adapter to hold the cell. Instruments are usually supplied with the standard adapters. The size of the cell would dictate the path length of light passing through the sample. Again, ensure you have selected the correct size of cell for your desired test.
Sample cells come in a range of materials, typically plastic, glass or quartz. Different materials will also have varying path lengths. The method sheet will not only detail the shape/size of sample cell to be used but it will also specify the material. In some instruments for particular methods, they may advise to use a glass sample cell when measuring the parameter in the low range and plastic when measuring it in the high range. In this case, make sure you calibrate with the same material of sample cell for each measurement.
Pour Thru Cell
The use of a pour thru cell allows for a rapid measurement without requiring the use of individual sample cells. The pour-thru cell fits into the cell compartment on your unit and a sample is passed through by using a funnel with tubing connection. (Note: certain chemistries are not compatible with the pour-thru cell, please check your method sheet for full compatibilities). Due to the intricate nature of the design, cleaning of this cell can prove to be tricky. Here, we describe how to clean your pour thru cell.
The Hach sample cells described above are not to be confused with their separate LCK vial range. Sample cells are used along with separate test reagents such as tablets or powders (pre-measured reagent powders produced by Hach are known as powder pillows) and utilise Hach chemistry. LCK vials are 13mm vials containing pre-dosed reagents for your test and utilise Lange chemistry. The Hach sample cells can be used in the full range of Hach branded meters, from the DR300 up to the DR6000. The LCK vials can only be used in the DR1900 and higher.
Our range of Hach sample cells and other accessories and adapters can be found here. If you need any assistance in choosing the correct sample cell for your instrument and application then please do contact us using the form below. Alternatively, email our technical support team at firstname.lastname@example.org