Gold leaf electrochemical flow cell for determination of iodide in nuclear emergency tablets.

This work introduces an innovative gold-leaf flow cell for electrochemical detection in flow injection (FI) analysis. The flow cell incorporates a hammered custom gold leaf electrochemical sensor. Hammered gold leaves consist of pure gold and are readily available in Thailand at affordable prices (approximately $0.

Disposable Microchamber with a Microfluidic Paper-Based Lid for Generation and Membrane Separation of SO Gas Employing an In Situ Electrochemical Gas Sensor for Quantifying Sulfite in Wine.

This work presents a fully disposable microchamber for gas generation of a sample solution. The microchamber consists of a cylindrical well-reactor and a paper-based microfluidic lid (μFluidic lid), which also serves as the reagent loading and dispensing unit. The base of the reactor consists of a hydrophobic membrane covering an in-house graphene electrochemical gas sensor.

Simplified fabrication of laminated paper-based analytical device (LPAD) with color-palette mobile app for analysis of salicylic acid in pharmaceutical products.

In this work, we present for the first time, a simplified fabrication of a laminated paper-based analytical device (LPAD) with a free-mobile app, Palette Cam, for image analysis. A filter paper is cut in a rectangular shape (9 × 3 cm) and placed between a top laminating sheet with punched holes and a bottom laminating sheet. The holes allow accessibility of liquid on the paper.

Simple gunshot residue analyses for estimating firing distance: Investigation with four types of fabrics.

This work presents two simple methods for estimating the firing distance from the gunshot residues (GSRs) on fabric targets. Four types of fabric targets, namely twill weave denim cotton-polyester (80/20), jersey knitting 100% cotton, plain weave cotton-polyester (80/20) and plain weave cotton-polyester (60/40), were employed. The firing tests were carried out using these white fabrics as targets at distances of 5-100 cm, respectively.

WinMLR program for the determination of sorbic and benzoic acids in food samples.

The program WinMLR has been developed to quantify sorbic and benzoic acids in soft drinks, fruit juices, and soy sauce by making a multilinear regression treatment of experimental data to a linear combination of standard signals. The spectra of sorbic and benzoic acid and samples were obtained from a conventional spectrophotometer, which has been saved in an ASCII file to be applied with the WinMLR program. Before to determine sorbic and benzoic acids in samples, the wavelength validation and calibration parameters were studied.

Simple and Equipment-Free Paper-Based Device for Determination of Mercury in Contaminated Soil.

This work presents a simple and innovative protocol employing a microfluidic paper-based analytical device (µPAD) for equipment-free determination of mercury. In this method, mercury (II) forms an ionic-association complex of tetraiodomercurate (II) ion (HgI) using a known excess amount of iodide. The residual iodide flows by capillary action into a second region of the paper where it is converted to iodine by pre-deposited iodate to liberate I under acidic condition.

Development of a microfluidic membraneless vaporization flow system for trace analysis of arsenic.

A new design of a membraneless vaporization (MBL-VP) unit coupled with a specific flow system is presented for the determination of arsenic at trace levels using a hydride generation process. The MBL-VP unit contains two concentric conical reservoirs, with the outer cone selected as the donor reservoir. The volume of the outer donor reservoir is thereby greater than the acceptor volume, necessary for holding sufficient sample and reagents for the generation of arsine gas by reaction between As(iii) and sodium borohydride under acidic conditions.

Simple Flow-Based System with an In-Line Membrane Gas-liquid Separation Unit and a Contactless Conductivity Detector for the Direct Determination of Sulfite in Clear and Turbid Food Samples.

This study presents a simple flow-based system for the determination of the preservative agent sulfite in food and beverages. The standard method of conversion of sulfite ions into SO gas by acidification is employed to separate the sulfite from sample matrices. The sample is aspirated into a donor stream of sulfuric acid.

Dual-Purpose Photometric-Conductivity Detector for Simultaneous and Sequential Measurements in Flow Analysis.

This work presents a new dual-purpose detector for photometric and conductivity measurements in flow-based analysis. The photometric detector is a paired emitter-detector diode (PEDD) device, whilst the conductivity detection employs a capacitively coupled contactless conductivity detector (C4D). The flow-through detection cell is a rectangular acrylic block (ca.

Green analytical method for simultaneous determination of salinity, carbonate and ammoniacal nitrogen in waters using flow injection coupled dual-channel C4D.

A flow injection analysis system (FIA) for the simultaneous determination of salinity, carbonate and ammoniacal nitrogen has been developed and reported in this paper. FIA incorporating membrane units was used, not only for the separation of the gaseous carbon dioxide and ammonia, but also for on-line dilution in the salinity measurement. The sample was injected via a 10-port valve with two sample loops.

Microfluidic Paper-based Analytical Device for Quantification of Lead Using Reaction Band-length for Identification of Bullet Hole and Its Potential for Estimating Firing Distance.

A low-cost and user-friendly microfluidic paper-based analytical device (μPAD) was developed for identification of bullet hole from gunshot residue (GSR) on cotton fabric target. The device (25 × 82 mm) is made of filter paper with a printed pattern consisting of a circular sample loading reservoir (6 mm i.d.

Simple in-house flow-injection capillary electrophoresis with capacitively coupled contactless conductivity method for the determination of colistin.

An in-house flow-injection capillary electrophoresis with capacitively coupled contactless conductivity detection method was developed for the direct measurement of colistin in pharmaceutical samples. The flow injection and capillary electrophoresis systems are connected by an acrylic interface. Capillary electrophoresis separation is achieved within 2 min using a background electrolyte solution of 5 mM 2-morpholinoethanesulfonic acid and 5 mM histidine (pH 6).

Cross injection analysis: concept and operation for simultaneous injection of sample and reagents in flow analysis.

This work presents a new flow injection strategy, called 'cross injection analysis' or CIA, an alternative cost-effective approach in flow analysis. The flow platform is made from a rectangular acrylic block, approximately 5×3×1.5 cm (x×y×z), with crossing cylindrical channels drilled out along the x- and y-axis of the block.

Direct injection of human serum and pharmaceutical formulations for glucosamine determination by CE-C(4)D method.

A simple CE-C(4)D method has been developed for the determination of glucosamine by direct injection of human serum and pharmaceutical samples. Glucosamine was electrokinetically injected and analysed in its protonated form using 20mM MES/His (pH 6) as background electrolyte in order to separate it from the matrix and to provide a better response to the C(4)D detector. Separation of glucosamine in human serum and pharmaceutical samples was performed in 3 min without the need for protein precipitation or matrix removal.

A low-cost method for determination of calcium carbonate in cement by membraneless vaporization with capacitively coupled contactless conductivity detection.

This work presents a flow analysis method for direct quantitation of calcium carbonate in cement without pretreatment of the sample. The method is based on online vaporization of CO(2) gas following acidification of the sample inside a small chamber that has a flow of acceptor solution passing around it. Solubilization of the CO(2) gas into the acceptor stream changes the conductivity of the acceptor solution causing an increase of signal at the capacitively coupled contactless conductivity detection (C(4)D) placed at the outlet of the vaporization chamber.

Kinetic-spectrophotometric method for the determination of trace amounts of bromide in seawater.

A novel simple, sensitive and rapid kinetic-spectrophotometric method is proposed for the determination of trace amounts of bromide. The method is based on its catalytic effect on the oxidation of methylene blue (MB) by hydrogen peroxide in strongly acidic solution. The oxidation reaction is activated by large amounts of chloride and can be monitored spectrophotometrically by measuring the decrease in the absorbance of MB at 746 nm.

Novel oxidation reaction of prochlorperazine with bromate in the presence of synergistic activators and its application to trace determination by flow injection/spectrophotometric method.

A simple and fast flow injection spectrophotometric method for the determination of bromate in water samples was developed. The detection system is based on the oxidation of prochlorperazine (PCP) with bromate in strongly acidic medium. Large amounts of chloride and bromide was found, for the first time, to act as an activator, and to enhance the sensitivity for bromate detection.