San++ continuous flow analyzer for ultra-low level seawater analysis


Seawater analysis is an essential part of environmental monitoring. High-quality nutrient data retrieved over time periods can give us valuable information regarding our ecosystem.

Determination of nutrients such as ammonia, nitrate, nitrite and phosphate in seawater can create many challenges for a laboratory. In addition to the requirement for ultra-low nutrient concentrations, other challenges such as the high contamination risk, short life time of the sample and matrix interferences can present problems for the laboratory. Thus analysis of seawater nutrients requires qualified personnel, optimized methods and a robust, highly accurate and sensitive instrumentation.

The Skalar San++ continuous flow analyzer has been successfully used for decades in seawater laboratories and on board of ships worldwide. The analyzer is ideal for the determination of extremely low nutrient concentrations in seawater and provides high quality, accurate and highly reproducible results.

Typical analysis data of the San++ analyzer:


Ranges: 0.07-35.7 µM N

Minimum Detection Limit (MDL): 0.009 µM N

RSD (%): 0.43%

Regression (r): 0.99998

Nitrate + Nitrite

Ranges: 0.07-71.4 µM N

Minimum Detection Limit (MDL): 0.005 µM N

RSD (%): 0.35%

Regression (r): 0.99994


Ranges: 0.07-71.4 µM N

Minimum Detection Limit (MDL): 0.005 µM N

RSD (%): 0.38%

Regression (r): 0.99987


Ranges: 0.03-32.3 µM P

Minimum Detection Limit (MDL): 0.003 µM P

RSD (%): 0.35%

Regression (r): 0.99942

CFA San++ system
Matrix detector

The San++ can be equipped with an unique digital turbo matrix detector to provide true optical matrix correction. This detector is especially designed to compensate automatically for changing salinities between seawater samples. The matrix correction is accomplished by optically splitting the light beam after passing the flow cell and measuring at two different wavelengths. The absorbance from the correction wavelength is subtracted from the measurement wavelength, thus the final result is automatically corrected for any background interference. In addition the special construction of the flow cell minimizes carry over and avoids the so-called “Schlieren effect” , the turbulence which is caused by differences in salinities concentrations, scattering the light and resulting in erratic signals.

The flexible design and optional work platform makes the San++ the best choice for seawater analysis. The completely closed instrument can be set either to analyze individual samples with an autosampler or in its on-line capability on board research vessels analyzing continuously multiple parameters at different depths whilst the ship is sailing. Optionally, the analyzer can be equipped with a diluter station for automatic pre– and post-dilutions of the samples and automatic standard preparation.

Specifically for ammonia analysis, the San++, can also be equipped with an analysis method based on fluorimetry. Advantages of this method are simplicity, no use of phenol reagent, sensitive and no matrix interferences.