Global FIA miniSIA-2

The Global FIA miniSIA-2 combines the power of FIA and SIA in a single instrument without need for any hardware changes. The system is equipped with two milliGAT pumps coupled to twin heated holding coils.  The tubing from these two holding coils merge at the center of a Chem-on-Valve™ (COV) monolithic manifold. This configuration allows the simultaneous merging of two streams which is a characteristic feature of FIA and a necessity for many chemiluminescence reactions.

The sample port has an inlet and outlet which meet on the face of the COV rotor.  Thus the sample can be primed to the valve without drawing sample into the rest of the manifold where it can cause carryover.  The sample port can also be primed with the next sample while the present measurement is underway by using the second milliGAT pump (A) or miniaturized metering pump.

The Global FIA miniSIA-2 is used for the determination of trace levels of zinc in water samples including seawater samples. The method is based on work reported by Grand et al[1]. The sample is pumped through a mini-column loaded with Toyopearl AF-Chelate-650M resin. The target analyte (zinc) and other complexing cations are retained, while the (seawater) matrix is washed out.

The zinc complex is passed through a flow cell where the fluorometric measurement takes place.  The excitation wavelength for the zinc complex is 494 nm and the emission wavelength is 516 nm. A high intensity blue LED (CREE XLAMP XP-E2) is used as excitation source and the light form this source is filtered through a 480 nm CWL 30 nm FWHM bandwidth optical filter. The fluorescent emission is detected using a photon counter equipped with a 535nm CWL 50 nm FWHM bandwidth optical filter. Measurement time is dependent on the volume of sample loaded – for a 1mL sample volume, the measurement time is approximately 6 minutes per measurement.