Determination of the potassium content of explosive residues using miniaturised isotachophoresis

Abstract

A new method has been developed to allow the determination of potassium in post-explosion residues to be made using miniaturised isotachophoresis. The method is based on the use of a caesium leading ion with 4.5 mM 18-crown-6 ether added to retard the potassium to allow reliable determinations to be made. With the conditions selected no interference was noted from other small inorganic cations, such as ammonium, barium, calcium, magnesium, sodium or strontium. The method was successfully applied to the analysis of seven samples containing explosive residues obtained from the unconfined burning of several flash powders. The procedure was found to offer good linearity for potassium determinations over the concentration range of 1.25-150 μg/mL with a coefficient of determination of 0.999 achieved.

Recent progress in analytical capillary isotachophoresis

“…There is continued interest in on‐chip applications of ITP. Prest et al described a method for determination of potassium content in explosive residues using ITP on chip with conductivity detection. No interference was found from other small inorganic cations (ammonium, alkali, and alkali earth metals).…”

Continuous Molecular Concentration and Separation Using Pulsed-Field Conductive-Wall Single-Buffer Teı́chophoresis

“…Micro total analysis systems (μTAS) are miniaturized platforms that can perform liquid handling and processing operations, such as sample preparation, molecular concentration, separation, and target analyte detection, within a single device or an integrated system. Over the last few decades, significant progress has been made in developing μTAS components and platforms for a broad range of applications, including point-of-care (POC) diagnostics, environmental monitoring, metabolic profiling, and use in single-cell analysis. − Applications utilizing μTAS can benefit from significant time-savings and reduced sample volumes when compared to their conventional laboratory counterparts. While there has been advancement in device microfabrication, optical integration, and liquid handling technologies, the ability to preconcentrate and detect low-concentration analytes entirely on a single μTAS device, or chip, without some degree of external handling remains challenging.…”

“…The charged analytes then continue to accumulate and focus into concentrated bands in order of decreasing electrophoretic mobility as they electrophoretically traverse down the channel length under capillary electrophoresis where they ultimately exit the channel and can be extracted in a concentrated/purified form. Due to its versatility and raw concentrating power, ITP has been used as a preconcentration method for a wide variety of ionic and molecular analytes, including concentrating potassium in explosive residues, bacteria in water, and rRNA indicative of urinary tract infections in urine. ,, ITP has also been used to concentrate biomarkers such as RNA and DNA for enhanced RT-qPCR. , Furthermore, ITP also offers high separation resolutions capable of performing chiral separations and separating mitochondrial proteomes. , To date, the highest ITP concentration factor reported is from Santiago et al, where they reported a ∼two-million-fold concentration of the fluorescent dye AlexaFluor 488 using batch-driven ITP with capillary electrophoresis …”

“…Due to its versatility and raw concentrating power, ITP has been used as a preconcentration method for a wide variety of ionic and molecular analytes, including concentrating potassium in explosive residues, bacteria in water, and rRNA indicative of urinary tract infections in urine. 2,15,16 ITP has also been used to concentrate biomarkers such as RNA and DNA for enhanced RT-qPCR. 17,18 Furthermore, ITP also offers high separation resolutions capable of performing chiral separations and separating mitochondrial proteomes.…”

ITP of lanthanides in microfluidic PMMA chip

“…ITP is a nonlinear electrophoretic technique that focuses analytes into discrete zones: the analytes become ordered between a leading electrolyte (LE) and a terminating electrolyte (TE) according to their electrophoretic mobilities . ITP has the ability to concentrate analytes by several orders of magnitude and has been demonstrated in the analysis of large biomolecules including proteins , DNA , small molecules, including organic acids and inorganic ions .…”