Highly Sensitive Visual Fluorometry of Aluminium at ppb Level with Ring-like Solid Phase of Poly(vinyl alcohol)

Abstract

By constructing a self-ordered nearly perfect ring system, a new type of visual test method has been developed. Poly(vinyl alcohol) forms a sharp ring–like solid phase (10.6 mm diameter) when a 100-μl drop of its aqueous solution was evaporated on a poly(vinyl chloride) plate. Aluminium ion of 1 – 30 ppb has been determined visually as a fluorescent 1:1 chelate of 2,2′-dihydroxyazobenzene concentrated into the ring.

Engineered droplets for dried droplet solute deposition by mass spectrometric imaging

“…The deposition patterns of solutes from dried solvent droplets have been an active research topic in the last decade because of their wide practical significance in fields such as inkjet printing (Schena et al 1995;Sirringhaus et al 2000;Lim et al 2008) and chemical analysis (Karas and Hillenkamp 1988;Wei et al 1999;Ishida et al 1999;Huang et al 2004;Zhang et al 2003;Tuomikoski et al 2002;Jokinen et al 2009). Typically, instead of a uniform deposition, the solutes are preferentially deposited to the edges of the droplet (Conway et al 1997;Deegan et al 1997), resulting in a ring-like deposition pattern upon drying of the droplet.…”

“…During the pinned stage, solvent and solute flow from the center of the droplet to the edges to resupply the pinned contact line, causing the ring-like deposition pattern. Experimentally, the phenomenon has been studied using optical microscopy (Deegan et al 1997;2000;de Gans and Schubert 2004;Kajiya et al 2006;Chen et al 2007;Okubo et al 2009), fluorescent spectroscopy (Ishida et al 1999;Huang et al 2004;Dhavaleswarapu et al 2010;Kajiya et al 2008;Zhang et al 2008) and Raman spectroscopy (Zhang et al 2003;Kopecký and Baumruk 2006). The majority of the experimental work has dealt with the general case of a roughly circular droplet on a planar surface, but several groups have reported drying phenomena on more specific geometries.…”

“…The ring shaped deposition pattern has been utilized to improve the detection limits and the reproducibility of fluorescent signals of the drug tetracycline (Huang et al 2004) and trace amounts of aluminum (Ishida et al 1999) The ring concentration is also helpful in drop coating deposition Raman spectroscopy (Zhang et al 2003), but here the signal is also sensitive to the location of the measurement inside the ring, with spectra from the outer part of the ring being poorly reproducible (Kopecký and Baumruk 2006). Dried droplet deposition is also utilized in matrix assisted laser desorption ionization (MALDI) (Karas and Hillenkamp 1988) and surface assisted laser desorption ionization (SALDI) (Wei et al 1999) mass spectrometry (MS).…”

Microscopic determination of tetracycline based on aluminum-sensitized fluorescence of a self-ordered ring formed by a sessile droplet on glass slide support

“…Dried spot analysis, for example on the solid support such as thin film substrate including octadecylsilanized silica and poly(vinyl chloride) plate [9,10], has many advantages since it can form a nearly perfect ring system, and has a good reproducibility, allowing the technique to approach the detection capabilities of inductively coupled plasma mass spectrometry (ICPMS) [11] and digitally imaging facilities such as CCD camera [12]. By spotting a tiny amount of a liquid sample onto a thin film substrate, where it is subsequently dried into a small solid residue, the analytes are concentrated prior to analysis and the background arising from the sample substrate is further reduced [8].…”

“…When a droplet of dilute solution containing dispersed solutes is spotted onto a hydrophobic solid surface, the evaporation loss of solvent from the edge of the drop should be replenished by the solvent from the interior of the spotted drop in order to keep the edge of the drop pinned, an outward capillary flow occurs and then carries the dispersed solutes of the spotted drop outward which deposit along the edge of the droplet spot. The deposition of the solutes forms a self-ordered ring (SOR) [10,16,17]. Reports can be found for the formation of mesoscopic ring structures on solid surfaces by using a variety of materials including porphyrin derivatives, nano-particles and carbon nanotubes [18].…”