Pyxis SP-350RO, SP-395N, SP-395T, SP-400 and EM-400 Handheld Fluorometers

These five Pyxis handheld meters measure fluorescent tracers and chlorophyll-a directly in a water sample, with no reagent and no cuvette. The sample is filled directly into the measuring cell, and color and turbidity interference is compensated by internal algorithms. Four of them (SP-350RO, SP-395N, SP-395T, SP-400) share the same mechanical platform for fluorescence and UV tracer measurement; the EM-400 is a separate instrument for a different application, measuring in-vivo chlorophyll-a fluorescence. In Turkey, Mikron Proses (Üsküdar, Istanbul) provides application consulting on selecting the right meter for your tracer and measuring point.

Tracer or parameter · Measuring point → Send us your requirement

For an overview of portable instruments, see the guide on handheld water analyzers. The same brand’s colorimeters and multimeters are described on the SP-800, SP-208 and SP-210 and SP-505 and SP-600 pages.

SP-350RO: PTSA for reverse osmosis feedwater

The SP-350RO measures the PTSA tracer in reverse osmosis (RO) feedwater in the range 0-40 ppb, with a precision of 1% or 1 ppb. This range is narrowed, compared with the general-purpose PTSA meters of the same family (0-300 ppb), to the low tracer concentrations typical of RO applications. Color and turbidity are compensated automatically.

SP-395N: NDSA (research and boiler water)

The SP-395N measures NDSA by the UV fluorescence principle in the range 0-100 ppb, with a precision of 1 ppb and an accuracy of ±1 ppb. The manufacturer states clearly that this method is not wet chemistry and that results can vary with sample quality: in waters with a high organic load a false positive reading may occur, and in waters containing nitrite the reading will be falsely low, because nitrite absorbs UV light. The manufacturer states that in systems with consistent feed water quality and no known organic contamination the instrument is very accurate compared with wet chemistry methods, while in surface feed water or heavily organic-loaded systems this technology is less suitable.

SP-395T: tolyltriazole (TTA)

The SP-395T measures the azole corrosion inhibitor tolyltriazole (TTA) by UV fluorescence in the range 0.1-10.0 ppm, with a precision of 0.1 ppm and an accuracy of ±0.1 ppm. Sample acidification is not required, and color and turbidity are compensated automatically. As with the SP-395N, nitrite-containing water affects the UV measurement; in this case the manufacturer states that a falsely high value will be read.

SP-400: PTSA + conductivity (dual channel)

The SP-400 measures, from the same sample at the same time, PTSA (0-300 ppb, ±1% or ±1.0 ppb; 365 nm excitation and 410 nm emission, ±1 nm) and conductivity (0-15,000 µS/cm). The conductivity accuracy depends on the range: ±10% or ±0.5 µS/cm at 0-20 µS/cm, ±1% at 20-10,000 µS/cm and ±2% at 10,000-15,000 µS/cm. For a stable conductivity reading the manufacturer states that 5 seconds should be allowed.

EM-400: in-vivo chlorophyll-a

The EM-400 is designed for an application different from the PTSA, TTA and NDSA meters: it measures the concentration of in-vivo chlorophyll-a, with a 470 nm LED excitation and a 650 nm emission wavelength (±1 nm), over 0-50 ppb, with a precision of 0.1 ppb and an accuracy of ±1% or ±0.1 ppb. The instrument is pre-calibrated for chlorophyll-a in the range 0-50 ppb and can be recalibrated in the field with chlorophyll-a standard solutions of 0, 10, 20 and 50 ppb.

Common platform (SP-350RO / SP-395N / SP-395T / SP-400)

These four instruments share the same mechanical platform: 160 × 74 × 33 mm, 310 g, a 320 × 240 TFT-LCD display, four AA alkaline batteries (typical battery life 10,000 readings), a sample temperature range of 4-41 °C, an adjustable measurement cycle of 15-999 minutes, IP67 protection and wireless configuration in the uPyxis app over Bluetooth 5.0. Each has a turbidity over-range alarm that warns on excessively turbid samples and a LOCK-IN function that holds the value once the measurement has stabilized. The EM-400’s body size (170 × 80 × 45 mm, 400 g) and battery life (typically 3,200 readings) differ from this common platform.

Which instrument for which tracer or application

The choice depends on the chemical to be tracked: SP-350RO for low-level PTSA in RO feedwater, SP-395N for NDSA verification in boiler water or research, SP-395T for the azole (TTA) level, SP-400 where conductivity is needed alongside the PTSA tracer, and EM-400 for chlorophyll-a. Tell us which chemical you want to track and the details of your measuring point, and we will define the right instrument together with you.