Determination of Manganese in Whole Blood by Cathodic Stripping Voltammetry with Indium Tin Oxide

Abstract

Manganese (Mn) is a required trace metal in the body. In recent years however, it has garnered significant attention as a developmental neurotoxin in children with chronic exposure. It has been linked to complications such as memory loss with negatively associated IQ scores, attention deficit hyperactivity disorder (ADHD), and in extreme cases, the development of a Parkinson's disease analogue‐manganism. Cathodic stripping voltammetry (CSV) has proven to be a suitable method for electroanalytical determination of Mn. We have established Mn CSV using indium tin oxide (ITO) as the working electrode for the determination of Mn in bovine whole blood after an acid digestion. Reliable, accurate, and precise results were obtained, as only 9 % variation in the digested blood was observed. The CSV results were compared with graphite‐furnace atomic absorption spectroscopy (GF‐AAS) and inductively coupled plasma‐ mass spectrometry (ICP‐MS) and favorable agreement across the methods was observed. Due to ITO's excellent positive potential window and stability under harsh environments, this method could be applied to other oxide‐forming transition metals detectable by CSV.

Indium Tin Oxide Film Characteristics for Cathodic Stripping Voltammetry

“…Limit of detections (LODs) of 5 nM (0.27 ppb) and 1 nM (0.05 ppb) were reported on the bare and coated ITO, respectively . In a follow-up paper, the ability to detect Mn in digested bovine whole blood samples using ITO with CSV was reported; the results were comparable to that obtained with inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectroscopy (GF-AAS) . Mn detection is important to ensure that its concentration in drinking water is below the maximum contaminant level (MCL) of 50 ppb set by the United States Environmental Protection Agency (US EPA).…”

“…27 In a follow-up paper, the ability to detect Mn in digested bovine whole blood samples using ITO with CSV was reported; the results were comparable to that obtained with inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectroscopy (GF-AAS). 32 Mn detection is important to ensure that its concentration in drinking water is below the maximum contaminant level (MCL) of 50 ppb set by the United States Environmental Protection Agency (US EPA). Additionally, it is important to monitor concentrations in human blood (4−15 ppb), urine (1−8 ppb), and serum levels (0.4−0.85 ppb) due to the toxic health effects of Mn.…”

Validation of Electrochemical Sensor for Determination of Manganese in Drinking Water

“…23−30 Stripping voltammetry is one of the most popular electrochemical techniques for the determination of trace levels of heavy metals, including Mn. 23,24,31,32 It consists of two steps, as shown in Figure 1a. First, the metal is deposited at the electrode by controlled potential electrolysis, which serves to preconcentrate the metal analyte on the electrode surface.…”

“…Since classical analytical methods cannot easily or rapidly assess Mn levels at point-of-use (POU), alternative methods using electroanalytical techniques have been proposed. These techniques offer relatively low limits of detection (∼ng/L), coupled with miniaturization for POU measurements. − Stripping voltammetry is one of the most popular electrochemical techniques for the determination of trace levels of heavy metals, including Mn. ,,, It consists of two steps, as shown in Figure a. First, the metal is deposited at the electrode by controlled potential electrolysis, which serves to preconcentrate the metal analyte on the electrode surface.…”

“…In the second step, the deposited metal is removed or “stripped” from the electrode by an appropriate potential scan that either oxidizes or reduces it back to ionic form in the solution, and the resulting current signal is used to quantify the metal. Although stripping voltammetry can be done at either the anode (reduction) or the cathode (oxidation), Mn cathodic stripping voltammetry (CSV) has proven to offer superior performance and has been reported to use carbon, − boron-doped diamond, and indium tin oxide ,, electrodes. Our group has also reported on the determination of Mn using miniature palladium (Pd) and platinum (Pt) electrodes.…”