The Center for Water and Environmental Analysis specializes in the determination of inorganic ions in water samples and the chemical composition of environmental samples (e.g., soil, sludge and rocks). Our instrumentation comprises the Dionex DX-500 Modular System, a Perkin-Elmer Optima 2000 DV Inductively Coupled Plasma — Optical Emission Spectrometer and a PSA Excalibur Atomic Fluorescence Spectrometer. We provide these analyses to the public, research institutions, government agencies and universities. For more information please contact us.

The common anions, F-, Cl^-, Br-, NO₂^-, NO₃^-, HPO₄^2- and SO₄^2- are determined by ion chromatography using the Dionex DX-500. Analyses are performed in accordance with the EPA Method 300.0, which is approved for drinking and environmental water samples.

The detection limits for the Dionex DX-500 Modular System with IONPAC AG14 Guard Column and IONPAC AS14 Analytical Column are as follows:
 

Cation and Trace Element Determination in Water

Up to 70 elements can be detected at trace levels by inductively coupled plasma-optical emission spectrometry (ICP-OES). Analyses are performed in accordance with the EPA Method 700.0, which is approved for drinking and environmental water samples.

The Perkin Elmer Optima 2000 DV is considered the benchmark in trace elemental ICP-OES analysis. It experiences the least amount of interferences of any analytical procedure available. Chemical interferences are eradicated by the high temperature plasma. Physical interferences are almost nullified by its multielement capability. Spectral interferences are largely decreased by the availability of many emission lines for any element combined with background correction techniques facilitated by the WinLab 32 software. Detection limits for this instrument.

The  elements As, Te, Bi, Pb, Sb and Se are routinely analyzed to levels as low as 5 -10 ppt (ng/L). The elements are converted into their hydrides (e.g., AsH₃) and then analyzed by Atomic Fluorescence Spectrometry (AFS). In addition to the determination of total concentrations we also provide speciation of arsenic (arsenite, arsenate, MMA and DMA) and of selenium (selenite and selenate). This is done via species separation in an ion exchange column prior to hydride formation. Detection imits are in the 1 ppb (µg/L) range.

Analysis of Soils, Sludge and Rocks

These samples have to be dissolved into an aqueous medium prior to analyses by either ICP-OES or AFS. We employ a variety of acid digestion methods whose application depends on the sample matrix and elemental emphasis. We also provide a six step sequential extration analysis. For more info contact us.

Quality Control

The University of South Florida Center for Water Analysis operates by a formal quality control program so the accuracy of the testing is guaranteed. We are in strict compliance with all rules and regulation handed down by the EPA Office of Water as stipulated by the Environmental Monitoring Methods Council. This includes formats, conventions, regulation of methods, standards, reagents, sample collection, preservation, storage, quality control, calibration, standardization, procedure, data analysis, calculations, and method performance.

All standards are purchased by reputable sources and are diluted with de-ionized type I reagent grade 18MW -cm resistance water or better. An independently certified standard (QCS, ERA or SPEX) is inserted after every twenty samples to ensure ongoing running accuracy. The calibration curve must be verified on each working run and after every twenty samples. Spikes are also inserted every twenty runs with 10% of the working stock and 90% of sample. Recovery for all controls (both independent and in house) must fall within + or - 10% of expected result.