Exploiting an automated microfluidic hydrodynamic sequential injection system for determination of phosphate.

A microfluidic hydrodynamic sequential injection (μHSI) spectrophotometric system was designed and fabricated. The system was built by laser engraving a manifold pattern on an acrylic block and sealing with another flat acrylic plate to form a microfluidic channel platform. The platform was incorporated with small solenoid valves to obtain a portable setup for programmable control of the liquid flow into the channel according to the HSI principle.

Sequential Injection Chromatography with an Ultra-short Monolithic Column for the Low-Pressure Separation of α-Tocopherol and γ-Oryzanol in Vegetable Oils and Nutrition Supplements.

A low-pressure separation procedure of α-tocopherol and γ-oryzanol was developed based on a sequential injection chromatography (SIC) system coupled with an ultra-short (5 mm) C-18 monolithic column, as a lower cost and more compact alternative to the HPLC system. A green sample preparation, dilution with a small amount of hexane followed by liquid-liquid extraction with 80% ethanol, was proposed. Very good separation resolution (R = 3.

Quantitative TLC-Image Analysis of Urinary Creatinine Using Iodine Staining and RGB Values.

Digital image analysis of the separation results of colorless analytes on thin-layer chromatography (TLC) plates usually involves using specially tailored software to analyze the images generated from either a UV scanner or UV lamp station with a digital camera or a densitometer. Here, a low-cost alternative setup for quantitative TLC-digital image analysis is demonstrated using a universal staining reagent (iodine vapor), an office scanner and a commonly available software (Microsoft Paint) for analysis of red, green and blue colors (RGB values). Urinary creatinine is used as a model analyte to represent a sample in complicated biological matrices.

Green analytical methodology using Indian almond (Terminalia catappa L.) leaf extract for determination of aluminum ion in waste water from ceramic factories.

The use of natural reagents from plant extracts for chemical analysis is one of the approaches in the development of low cost and environmentally friendly green analytical chemistry methodology. Here, crude extract from Indian Almond (Terminalia Catappa L.) leaves was used for colorimetric determination of aluminum by monitoring the absorbance of the Al(3+)-extract complex at 435 nm.

Flow-based systems for rapid and high-precision enzyme kinetics studies.

Enzyme kinetics studies normally focus on the initial rate of enzymatic reaction. However, the manual operation of steps of the conventional enzyme kinetics method has some drawbacks. Errors can result from the imprecise time control and time necessary for manual changing the reaction cuvettes into and out of the detector.

Flow injection/sequential injection analysis systems: potential use as tools for rapid liver diseases biomarker study.

Flow injection/sequential injection analysis (FIA/SIA) systems are suitable for carrying out automatic wet chemical/biochemical reactions with reduced volume and time consumption. Various parts of the system such as pump, valve, and reactor may be built or adapted from available materials. Therefore the systems can be at lower cost as compared to other instrumentation-based analysis systems.

Sequential injection Lab-at-valve (SI-LAV) segmented flow system for kinetic study of an enzyme.

A sequential injection-Lab-at-valve (SI-LAV) segmented flow system for kinetic study of an enzyme was developed. Air segments were introduced for separation of enzyme and substrate zones and separation of the stacked zones from the carrier solution which ensure the measurement of the initial rate and minimize the dilution/dispersion effect. The open- ended mixing chamber makes it possible to use air segments in the flow system without the need for additional air segment discarding steps.

Exploiting green analytical procedures for acidity and iron assays employing flow analysis with simple natural reagent extracts.

Green analytical methods employing flow analysis with simple natural reagent extracts have been exploited. Various formats of flow based analysis systems including a single line FIA, a simple lab on chip with webcam camera detector, and a newly developed simple lab on chip system with reflective absorption detection and the simple extracts from some available local plants including butterfly pea flower, orchid flower, and beet root were investigated and shown to be useful as alternative self indicator reagents for acidity assay. Various tea drinks were explored to be used for chromogenic reagents in iron determination.

Flow injection determination of iron ions with green tea extracts as a natural chromogenic reagent.

A green chemistry system that utilizes natural extract as an alternative reagent for determination of metal ions has been investigated. The extract of green tea, a common beverage, is used for quantification of iron. The green tea extract was prepared in acetate buffer pH 4.

Sequential injection-cation exchange micro-column system for hemoglobin typing to differentiate HbE carriers.

A weak cation exchange micro-column was incorporated into a sequential injection (SI) system to perform automatic hemoglobin (Hb) typing as an alternative way to measure HbE. Separation of HbF, HbA and HbA(2)/HbE was performed using phosphate buffer solutions in the pH range of 6-7 to create pH gradient mobile phase. The resultant chromatogram showed relative amounts of HbE to other types of hemoglobins in more quantitative detail than the conventional techniques such as dichlorophenol indophenol precipitation and micro-column anion exchange.

Sequential injection-immunoassay system with a plain glass capillary reactor for the assay of hyaluronan.

A sequential injection capillary immunoassay system (SI-CI) was developed to automate the multi-step competitive bioassay procedures for hyaluronan (HA), a potential biomarker for liver and cancer diseases. Biotinylated HA-binding proteins (b-HABPs), anti-biotin conjugated with horseradish peroxidase (anti-b-HRP) and substrate 3,3',5,5' tetramethylbenzidene (TMB) were employed. An ordinary glass capillary was utilized as a bio-reactor where competitive assay took place.

Sequential injection-capillary immunoassay system for determination of sialoglycoconjugates.

An automatic immunoassay system for an assay of sialoglycoconjugates was developed based on the sequential injection technique. A cost effective plain glass capillary tube was used as a solid surface for immobilization of biomolecules via a simple physical adsorption which is adequate to tolerate the force of solution flowing through the capillary during the multi-steps immunoassay process. Immunoassay could be performed with many improvements-rapidity per sample as compared to the conventional micro-plate format (40 min vs.

A stopped flow system with hydrodynamic injection for red blood cells osmotic fragility test: possibility for automatic screening of beta-thalassemia trait.

Simple instrumentation and procedure with stopped flow system coupled to hydrodynamic injection and spectrophotometric detection were developed for automatic osmotic fragility test (OFT). OFT is a test for abnormal red blood cells based on the kinetics of their rupturing in a hypotonic saline solution. A portion of red cells was merged on-line with a hypotonic saline solution.

Exploiting guava leaf extract as an alternative natural reagent for flow injection determination of iron.

Guava leaf extract is utilized as an alternative natural reagent for quantification of iron. The flow injection technique enables the use of the extract in acetate buffer solution without the need of further purification. Some properties of the extract such as its stability and ability to form a colored complex with iron were studied.

Sequential injection-ELISA based system for online determination of hyaluronan.

Sequential injection-bead-based immunoassay system has been developed. The main purpose is to make immunoassay process more automated by manipulating the precise delivery of micro-volumes of reagents and the precise timing of incubation and washing steps with a computer program that controls the bi-directional syringe pump. The manifold was designed with the aims of reducing back pressure from beads that act as solid surfaces for immobilization of the target substance, reducing dispersion and dilution of the reagent during incubation, and maximizing signal while minimizing incubation time.

Review on screening and analysis techniques for hemoglobin variants and thalassemia.

Thalassemia involves gene mutation that causes the production of an insufficient amount of normal structure globin chains while Hb variant involves gene mutation that causes the change in type or number of amino acid of the globin chain. It has been reported that some 200 million people worldwide had hemoglobinopathies of some sort. Attempts to develop effective and economical techniques for screening and analysis of thalassemia and Hb variants have become very important.

A simple flow injection-reduced volume column system for hemoglobin typing.

A flow injection (FI)-reduced volume column system was developed for hemoglobin (Hb) typing to be used as an initial screening method for thalassemia. The column was packed with 140 microl diethylaminoethyl (DEAE)-Sephadex A-50 ion exchange beads. Hb can be separated using Tris-HCl buffer solution with pH gradient 8.

Online assay of bone specific alkaline phosphatase with a flow injection-bead injection system.

Alkaline phosphatase (ALP) has been used as one of the biomarkers for bone resorption and liver diseases. Normally, total alkaline phosphatase is quantified along with other symptoms to determine the releasing source of the alkaline phosphatase. A semi-automated flow injection-bead injection system was proposed to conveniently and selectively assay bone alkaline phosphatase (BALP) based on its specific binding to wheat germ coated beads.

Exploiting flow injection system with mini-immunoaffinity chromatographic column for chondroitin sulfate proteoglycans assay.

A flow injection (FI) system with a mini-immunoaffinity chromatographic column was used to perform on-line assays of specific proteoglycans. The 300-microL mini-column contained beads coupled with monoclonal antibodies against the specific sulfation pattern of chondroitin sulfate proteoglycans, which have been reported to be a potential biomarker for cancer. The amount of these proteoglycans present was estimated indirectly from their protein content using the Bradford assay, which is an alternative to a direct carbohydrate assay.

Simple bead injection-flow injection system for the determination of copper.

We demonstrate the extended application of a simple bead injection-flow injection system with a modified simple colorimetric detection unit for the determination of low amount of Cu2+ in samples of different matrices (water and supplement tablet samples) with minimal sample pretreatment by employing ammonium pyrrolidinedithiocarbamate (APDC) reagent.

Novel approach for mono-segmented flow micro-titration with sequential injection using a lab-on-valve system: a model study for the assay of acidity in fruit juices.

A new concept for micro-titration using a "lab-on-valve"(LOV) system with sequential injection of mono-segmented flow is proposed. The performance of the system was demonstrated by the assay of acidity in fruit juices which is based on acid-base neutralization. A standard/sample solution containing citric acid, indicator, sodium hydroxide, were sandwiched between air segments and were aspirated in microliter volumes through a selection valve into a holding coil.