Kinetic Phosphorescence Analyzers for trace level detection of Uranium & Lanthanides

What is Kinetic Phosphorescence technology?

The Chemchek Kinetic Phosphorescence Analyzer (KPA) is a bench-top instrument that rapidly performs quench-corrected analysis for trace uranium with minimal sample preparation.

The KPA's technology is based on the measurement of a sample's phosphorescence taken at selected time intervals to determine the precise concentration of the analyte. Superb selectivity is achieved by use of three parameters: 

1. Excitation Wavelength
The uranium sample and
 reference are excited by firing the nitrogen laser at 337 nm. This excites the dye laser to produce an excitation wavelength of 420 nm. Each analysis is a repetition of 50 second cycles. A 3 nsec. laser pulse initiates each cycle.

2. Emission Wavelength
A 515-nm band-pass filter is used to filter the emission signal and to pass the 515-nm uranium peak. Phosphorescence is a delayed emission of 10 -4 -10 seconds. Sensitive photomultiplier tubes and photon counting circuitry count the phosphorescent decay events emitted from the sample and reference.

3. Decay Time
The measured phosphorescence is resolved over time to discriminate against other light emitting species. The counted phosphorescent events are sorted by time and accumulated in bins or time-gates. Time-gates for short times contain decay information for short-lived processes other than phosphorescence and are ignored. The time-gates selected will only contain decay information for phosphorescence.

Phosphorescence is measured by KPA as a function of time and relates it to the concentration of the analyte. Phosphorescence is a first order kinetic process, thus it is a simple matter to relate the sample signal to the concentration of the analyte by selecting the appropriate time domain. Reference data are used to correct results to background conditions.

The KPA's technology is easily applied to uranium chemistry. The KPA is unique for its analysis by "Oxidation State". U (VI) complexes are soluble and phosphoresce. U(IV) exists primarily as its oxide. KPA detects the emission from U(VI) present in solution as uranyl ion UO22+. However, U(IV) is insoluble and does not phosphoresce. Therefore, U(IV) is oxidized to U(VI) in acid before the sample is analyzed by KPA. Ultimately the KPA analyzes for chemical species.

The KPA is operated with an IBM compatible personal computer. The KPA offers control and data management via Chemchek's KPAWin software

KPA performance: Precision data for Chemchek instruments

Applications of KPA technology

Chemchek's Kinetic Phosphorescence Analyzer (KPA) is the superior analyzer for trace soluble Uranium. The KPA-11 instrument provides high levels of sensitivity, with detection limits in the parts-per-trillion range for water. Kinetic analysis of luminescence corrects results for matrix quenching; therefore, most real-world samples are analyzed directly. The instrument's speed, and selectivity, significantly reduces the amount of work and time to prepare and analyze samples. These characteristics make the KPA the instrument of choice for the routine analytical work performed in laboratories addressing uranium assay.  See the Applications page.

 

KPAWin Software

Chemchek's KPAWin software controls the operation of the KPA-11 and the storage and manipulation of the analytical data. Click here for more information.