Our rapid testing service for the quantitative determination of toxins produced by algal blooms has assisted water utilities throughout Australia and overseas respond to water quality issues caused by cyanobacteria.
Application
Cyanobacteria, known as blue green algae, are found in freshwater lakes, reservoirs, rivers, and marine waters and are of the most concern to many health and water authorities. Several species of cyanobacteria can produce potent toxins that have caused wildlife and domestic animal deaths.
These toxins include:
Hepatoxins — Microcystins and Nodularins
Microcystins are cyclic peptides produced mostly by Microcystis aeruginosa and several other species. There are over 70 structural variants but approximately 20 are most frequently detected in freshwater lakes, reservoirs, rivers and marine water. Nodularin, a similar cyclic peptide, is produced by Nodularia spumigena.
Microcystins and Nodularin can be determined, simultaneously, by HPLC/DAD. With a sample pre-concentration step, our NATA accredited method can report Microcystin-RR, -YR and –LR at the level of 0.1 μg /L, which far below that specified in the Australian Drinking Water Guideline. The reporting limit for Nodularin is also 0.1 μg /L. Intracellular and extracellular toxin are reported separately, and the total m-LR equivalent is calculated to comply with proposed guidelines.
We also have a NATA accredited method available to you to analyse Microcystins and Nodularins in scum samples.
Neurotoxins —Aanatoxin-a and Saxitoxins
Anatoxin-a, is a neurotoxic alkaloid. Our fully validated HPLC/MS/MS method produces the most reliable and accurate results with a fast turn-around time and an absolute confirmation. The reporting limit is 0.1 μg/L.
Saxitoxin known also as Paralytical Shellfish Poison (PSP), is a neurotoxin naturally produced by certain species of marine dinoflagellates and cyanobacteria.
The PSP neurototoxins consist of 18 compounds with vastly different toxicities and structures and are most difficult to analyse. Several techniques can be used for their determination. However, there is not a method that gives the reliable and accurate results, within the required reporting limits for surface water and drinking water, while, at the same time, giving a fast turn-around time.
The analytical method employed within the Organic Chemistry Laboratory is the HPLC/post-column derivertisation fluorescence detection technique. It requires three chromatographic runs and a high level of expertise in instrument operation and result interpretation. However, it is the only analytical method that can produce a complete separation and determination of saxitoxins at the required reporting limits. This validated method can report the individual toxins at 0.5 μg/L for both intracellular and extracellular toxins. STX equivalent also is calculated for determining the compliance with proposed guidelines.
Non-specific toxin — Cylindrospermopsin can be determined by HPLC/MS/MS method. Our fully validated method provides reliable and accurate results with a fast turn-around time and at the required reporting limit, 0.1 μg/L.
Many techniques are available for determining cyanotoxins, e.g. enzyme linked immunosorbent assay (ELISA), protein phosphatase inhibition assay, capillary electrophoresis (CE), and high performance liquid chromatograph (HPLC) coupled with various detection techniques such as photo diode array (PDA), fluorescence and mass spectrometry.
Of all the techniques, HPLC instrumental analysis is the most reliable and accurate. We have developed many HPLC methods and provides a comprehensive analytical service for a wide range of toxins, including microcystins, nodularins, anatoxin-a, cylindrospermopsins and saxitoxins. We also evaluate other assays such as ELISA kit and protein phosphatase inhibition assay, and compare them with HPLC methods.
All our HPLC methods are designed to analyse both extracellular toxins (dissolved toxins) and intracellular toxins (toxins inside cyanobacterial cells) and are fully validated with many NATA accredited.
Sampling requirement for microcystins and nodularin:
Minimum 1 L water sample or scum equivalent to 20 mg freeze-dried
HDPE plastic or glass bottle
Transport and store at 4°C
Sampling requirement for saxitoxins:
Minimum 500 mL water sample or scum equivalent to 20 mg freeze-dried
HDPE plastic or glass bottle
Transport and store at 4°C
Sampling Requirement for anatoxin-a and cylindrospermopsin:
Minimum 100 mL water sample or scum equivalent to 20 mg freeze-dried
HDPE plastic or glass bottle
Transport and store at 4°C
