TOC - Measurement of TOC and TN in Marine Water Algae Culture Solution
The culturing of microalgae in various types of nonedible biomass has been receiving considerable attention in recent years. In particular, microalgae that inhabit seawater are favored due to the low cost of the culture solution and the wide choice of culture locations. Various nutrients, such as nitrogen compounds, are added to these types of microalgae cultures. However, nutrient concentrations must be managed within an appropriate range depending on the type of microalgae and the culture conditions. The Shimadzu TOC-L Series Combustion Type Total Organic Carbon Analyzer can directly measure the total organic carbon (TOC) and total nitrogen (TN) content in high-salt samples such as seawater, without requiring dilution of the samples. Measurement samples were prepared by spiking seawater obtained from the Sea of Japan (coast of Fukui Prefecture) with potassium hydrogen phthalate as TOC and potassium nitrate as TN, to obtain equivalent concentrations of these measurement samples (1) to (5) at levels of 0 mg/L, 25 mg/L, 50 mg/L, 100 mg/L and 150 mg/L, respectively. Simultaneous TOC and TN measurement of these samples was then conducted using the TOC-LCPH + TNM-L.
Analytical Method
Measurement samples were prepared by spiking seawater obtained from the Sea of Japan (coast of Fukui Prefecture) with potassium hydrogen phthalate as TOC and potassium nitrate as TN, to obtain equivalent concentrations of these measurement samples (1) to (5) at levels of 0 mg/L, 25 mg/L, 50 mg/L, 100 mg/L and 150 mg/L, respectively. Simultaneous TOC and TN measurement of these samples was then conducted using the TOC-LCPH + TNM-L.
Table 1 Measurement Results
| Sample | TOC Measurement Value [mgC/L] ［mgC/L］ |
TN Measurement Value [mgN/L] ［mgN/L］ |
|---|---|---|
| Sample (1) (seawater only) | 1.05 | 0.21 |
| Sample (2) (spiked at 25 mg/L) | 25.8 | 24.7 |
| Sample (3) (spiked at 50 mg/L) | 51.7 | 49.1 |
| Sample (4) (spiked at 100 mg/L) | 102.1 | 101.2 |
| Sample (5) (spiked at 150 mg/L) | 151.4 | 152.8 |
TOC-L for Microalgal Biomass Monitoring
The TOC-L for Microalgal biomass measurement is a total organic carbon analyzer that permits accurate measurement of total organic carbon even if the sample is in the form of a suspension, such as microalgae, and with minimal impact due to sedimentation.