Introduction:

Analytica Laboratories (now part of ALS Global) is New Zealand’s leading honey testing laboratory. We have developed methods like the C4 Sugar Screening test and the 3-in-1 test that are now very commonly used by all New Zealand labs nowadays. In this article, I am going to give you a brief rundown on how we perform some of the common honey tests, to give you a better understanding of what your honey goes through once it arrives at our doors. Another good way to understand what we do in the lab is to come for a lab tour!

Sample Reception Process:

When your honey first arrives at our door, it will likely be arriving via a courier service. As a commercial lab, we service many industries including contaminated land, water, dairy, and honey just to name a few.

Once your honey is dropped off, it will head into our Sample Reception team to be receipted. Using the analysis request form that you send in with your samples, the team will register your honey into our laboratory information management system (called ‘LIMS’) and label the samples with unique identifying barcodes before sending it to the lab. If there are any problems interpreting your request form or with the samples we have received, the team will contact you to confirm. If all is fine, you will receive your sample receipt notifying you that your samples have arrived and are in the lab being tested.

Laboratory Analysis Process:

After your honey has been through sample reception, it will make its way to the lab. An important thing to note is that when honey reaches the lab it is completely anonymous to lab staff who the client is. This is an IANZ requirement which keeps any potential bias from interfering with the lab process.

The first step in the honey process is to thoroughly mix the honey, then weigh the honey into smaller subsamples for each test that the sample is needing. This ensures the proportion taking for testing is representative of the sample submitted. After the honey has been weighed out, the subsample will be sent off for testing and any leftover sample will be stored for potential retesting that may be required.

Performing the 3-in-1 and Leptosperin tests:

To analyse a sample for DHA, MG, HMF and Leptosperin, we use a technique called High Performance Liquid Chromatography (HPLC). This machine works by sending a carefully prepared solution of the honey at high pressure through a stainless-teel tube containing special absorbents, called a ‘column’. The idea is that the compounds in the sample all have different chemical properties so they will travel through this column at different speeds. By placing an optical detector at the end of the column we can measure when each compound comes out, and by determining the size of the signal we can determine the concentration. The end result is called a ‘chromatogram’, which is like a graph of the signal against time. An example is shown in Figure 1.

Performing the MPI Chemical Markers test:

Analytica use Liquid Chromatography-Mass Spectrometry (LC-MS) to analyse honey for the MPI Chemical Markers. This instrument follows the same principle as the HPLC instrument but rather than using an optical detector to create a chromatogram, we will run it through a mass spectrometer. This allows us to quantify analytes that are at much lower levels than what we could detect using HPLC alone. The mass spec works by spraying the eluent from a column into a fine mist, applying an electrical charge, then measuring the signals originating from particular masses corresponding to the compounds of interest. This gives very high sensitivity, and very high selectivity.

How do we interpret the data to get a result?

To interpret the data we first look at the chromatograms of the standards. Standards are verified solutions that contain known levels of each analyte. Using the results of the standards we tested, we can establish a mathematical relationship between the size of a signal and the corresponding concentration. By applying that relationship to the honey samples, we can determine their concentrations. We verify that the results are correct by checking quality control samples which are run with every single sample and every single analysis batch.

Conclusion:

Next time you receive your results, have a look at the method summary section to see what process your sample went through to get the result. Hopefully now you will have a better understanding of the chemistry based processes your honey has gone through!