Kate Grudpan

Chiang Mai University | CMU · Center of Excellence for Innovation in Analytical Science and Technology and Faculty of Science

The application of smartphone-based color evaluation of passive sampling devices for gases has only been sparsely reported. The present review aims to compile available publications with respect to the configuration of the passive samplers, conditions of smartphone photographing, analytical procedures for color detection and quantification (includi...

A sustainable procedure offering green, simple, and rapid analysis was developed to determine benzalkonium chloride (BKC) in pharmaceutical preparations. The determination using smartphones was based on the ion pair colorimetric reaction with bromothymol blue (BTB), which produces a yellow color. The intensity of the product color, which is proport...

The application of smartphone-based color evaluation of passive sampling devices for gases has only been sparsely reported. The present review aims to compile available publications with respect to the configuration of the passive samplers, conditions of smartphone photographing, analytical procedure for color detection and quantification (includin...

An investigation was made to use some vegetable oils, namely, extra virgin coconut oil, tea seed oil, soybean oil, and extra light olive oil, as alternative solvents for the simple green colorimetric liquid-liquid partitioning extraction determination of diphenhydramine hydrochloride (DPHH). The ion pair of DPHH and bromocresol green (BCG) in an aq...

Coconut oil as a natural solvent is proposed for green downscaling solvent extractive determination. Determination of Cu(II) using 1,5-Diphenylcarbazide (DPC) was selected as a model for the investigation. Cu(II)-DPC complexes in aqueous solution were transferred into coconut oil phase. The change of the color due to Cu(II)-DPC complexes in coconut...

A novel, cost-effective platform using a biodegradable sensor and a simple heat control unit was proposed for multi-sample formaldehyde (FA) assay in one run based on pervaporation. The biodegradable sensor was a composite starch gel attached to paper and immobilized with a mixture of color agents of modified 4-amino-3-hydrazino-5-mercapto-1,2,4-tr...

We proposed a specially designed sequential injection (SI) amperometric system coupling with a bioreactor for in-line glucose monitoring in cell culture. The system is composed of three main parts which are the bioreactor, SI system, and electrochemical detection unit. The bioreactor accommodates six individual cell culture units which can be opera...

A green and sustainable downscaled procedure was developed to perform smartphone-based colorimetric determination of fluoroquinolones in extemporaneous syrup formulations. The procedure functioned by complexing fluoroquinolones with metal ions, the most suited of which is a ferric ion, to produce a colored product in a 96-well plate combined with s...

An ultrasound-assisted, one-pot cloud point extraction was developed for the determination of iron in vegetable samples by UV-Visible spectrophotometry. This method was based on the complexation of iron with an environmentally-friendly natural chelating agent extracted from Dipterocarpus intricatus Dyer fruit at pH 5.5 in the presence of Triton X-1...

Iron-tannic nanoparticles were used as a new adsorbent for dispersive solid phase extraction (DSPE) synergized with cloud point extraction (CPE) to enrich four tetracyclines (oxytetracycline, tetracycline, chlortetracycline, and doxycycline) prior to high-performance liquid chromatographic determination. DSPE and CPE were performed simultaneously i...

A sustainable downscaled procedure using smartphone-based colorimetric determination of manganese (Mn(II)) was developed. This novel Mn(II) determination procedure is proposed using a simple, available microwell-plate platform and a smartphone as a detector. This approach is based on the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by periodat...

Dual determination of nitrite and iron was proposed by using a single greener sequential injection (SI) spectrophotometric system employing a simple single aqueous extract from Areca catechu Linn. The extract served as a natural reagent to replace N-(1-naphthyl)ethylenediamine (NED) of the Griess reagent with nitrite and 1,10-phenanthroline with ir...

A simple and reliable dispersive liquid-liquid microextraction (DLLME) coupled with smartphone-based digital images using crude peroxidase extracts from cassia bark (Senna siamea Lam.) was proposed to determine carbaryl residues in Andrographis paniculata herbal medicines. The method was based on the reaction of 1-naphthol (hydrolysis of carbaryl)...

A new biodegradable platform-based sensor for formaldehyde assay is proposed. Natural rubber latex was modified to polylactic acid–chloroacetated natural rubber polymer blend sheets. The polymer blend sheet was grafted using a water-based system with amine monomers as a platform, with a spot exhibiting positive polarity for immobilizing with anioni...

The COVID-19 pandemic has forced analytical chemistry educators in Thailand to change methods of teaching and learning to new normal ones. Higher education has faced additional challenges because of a lack of hands-on experiments and an increasing number of students in foundation chemistry courses being hindered from practicing skills. This work ai...

A low-cost and reliable analytical method based on the combination of a newly designed sticker-plastic sheet platform, digital image-based colorimetry and down scaled Kjeldahl digestion is proposed for the determination of protein content in food samples. The yellowish-brown colloidal products, obtained from the reaction between the ammonium-nitrog...

To minimize chemical waste and protect the environment, our team has used green analysis with natural reagents. In this work, we designed a natural-reagent assay kit for iron determination and implemented it in chemistry education in Thailand. The iron assay method was adapted from Thai local wisdom of testing water quality using guava leaves. The...

High performance liquid chromatography (HPLC) for catechins and related compounds in Miang (traditional Lanna fermented tea leaf) was developed to overcome the matrices during the fermentation process. We investigated a variety of columns and elution conditions to determine seven catechins, namely (+)-catechin, (-)-gallocatechin, (-)-epigallocatech...

A high-sensitivity green analytical methodology was developed for the spectrophotometric determination of tetracycline (TC), employing simultaneous injection effective mixing analysis (SIEMA). This is based on the chelation between tetracycline and zirconium, resulting in a yellow-colored product which exhibits maximum absorption at 420 nm. Under o...

In this paper, a novel antioxidant analysis is proposed using a simple minimized device based on moving drops as solution handling and a smartphone as a detector. This approach is based on the colorimetric determination of the scavenging activity against 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•), expressed as the half-maximal inhibitory concent...

A monolithic rod of polyurethane foam–[4-(2-pyridylazo) resorcinol] (PUF–PAR) as a simple chemical sensor for lead assays with smartphone detection and image processing was developed. With readily available simple apparatus such as a plastic cup and a stirrer rod, the monolithic PUF rod was synthesized in a glass tube. The monolithic PUF–PAR rod co...

Paper-based analytical devices (PADs) with four new designs could be fabricated using commercially available home-based scan-and-cut printer. They serve for miniaturised platforms for chemical analysis. Replication analysis of a sample together with the calibration (using the analyte standards at different concentrations) can be completed in a sing...

A modern chemical sensor system (M-CSS) was developed for the cost-effective chemical analysis of Thai precision and sustainable agriculture (TPSA), which is suitable in rural Thailand and elsewhere. The aim of this study was to achieve precision and sustainable agriculture (P-SA). The M-CSS functions according to the International Union of Pure an...

A simple flow injection FlameAAS for lead determination with an alginate-polyurethane composite (ALG-PUC) monolithic in-valve column has been developed. The ALG-PUC monolithic rod was prepared by mixing methylene diphenyl diisocyanate with polyol and sodium alginate with the ratio of 2:1:1 by weight for a 5 min polymerization reaction. It was then...

Exploiting natural reagents derived from plant extracts to develop analytical methods promote green chemistry. Betel nut (Areca catechu Linn.) was utilized as a natural reagent for determination of iron(III) by sequential injection spectrophotometry. This method was based on the reaction of iron(III) with natural reagent as betel nut in acetate buf...

A simple extract of Leucaena leucocephala (Lam) de Wit leaf containing mimosine is proposed as a natural color reagent for the determination of iron.. The extract exhibited the formation of Fe(III) with mimosine similarly to that of the commercially available mimosine. A linear calibration: A460 = 6.8 x 10⁻² [Fe(III)] + 8.2 x 10⁻²-, R² = 0.99 was o...

A simple cost-effective moving drop device, with solenoid valves control for programmable liquid handling, was developed for electrokinetic injection in capillary zone electrophoresis (CZE). With a CZE of 50-μm bore fused silica capillary tube and contactless conductivity detector (C4D), mixed anions (Cl⁻, NO3⁻, and SO4²⁻ as the model) solution was...

An enzymatic method for cost-effective and reliable spectrophotometry was described based on the catalytic reaction of peroxidase enzyme to detect and determine tetracycline. Daikon (Raphanus sativus L.), a local vegetable, was exploited as a source of peroxidase enzyme, extracted by a simple method and utilized for tetracycline detection without a...

A mono-segmented sequential injection lab-at-valve (SI-LAV) system for the determination of albumin, glucose, and creatinine, three key biomarkers in diabetes screening and diagnosis, was developed as a single system for multi-analyte analysis. The mono-segmentation technique was employed for in-line dilution, in-line single-standard calibration, a...

Carbaryl is a member of the carbamate family and commonly used as an insecticide. A cost-effective and reliable method to determine carbaryl and its metabolite 1-naphthol was developed based on alkaline hydrolysis of carbaryl into 1-naphthol followed by enzymatic reaction with peroxidase, extracted from jackfruit latex in the presence of 4-aminoant...

An environmentally friendly field-portable approach based on small-scale ultrasound-assisted extraction and micro-volume colorimetry was proposed for the determination of iron using natural reagent extracts from pomegranate peels. Ultrasound technology was utilized for the extraction of pomegranate peels in acetate buffer pH 5.5. Sonication paramet...

Magnetic ion-selective colorimetric microspheres based on surface modification of polystyrene beads (0.8 μm diameter) are reported for the first time. The common components of ion-selective optode sensing (chromoionophore, ion-exchanger and ionophore) and magnetic nanoparticles are adsorbed onto the surface of the polystyrene particles using a simp...

A simple and cost-effective analytical device based on gas pervaporation and diffusion method for determination of ammonia is proposed. The proposed device is consisted of a well microplate as a donor chamber and a natural indicator-immobilized paper (butterfly pea flower extract) as an acceptor sensor. This allows microliter-scale solution handlin...

Talanta has been known as one of the top ranking journals in (general) analytical chemistry. Applying a search term “Talanta” in Scopus, using the tool for analysis in there, some characteristics on Talanta were investigated. Tracing back for every 10 year period, by considering the citations relevant to the key words of the published papers, it ca...

We propose a simple greener colorimetric method for the determination of nitrate-nitrogen by operating on a 96-well microplate and using a smartphone camera as a simple detector. A slurry containing 0.3 mg zinc was used for reduction of nitrate to nitrite, the reduction solution was transferred to a 96-well microplate to react with Griess reagent t...

There is an urgent need for reliable seawater phosphate measuring tools to better assess eutrophication. Today, most accepted sensing approaches are based on the established colorimetric molybdenum blue assay. It requires one to modify the sample to strongly acidic conditions and to add various reagents, principally molybdate and reducing agent (e....

We propose the creation of reusable indicator-sorbed-solids, using anion-exchange resins or kaolin as supports, with the aim to reduce chemical use towards green analytical chemistry. Indicators (phenolphthalein, thymol blue and butterfly pea flower extract as a natural indicator) sorbed on a solid support, were employed in acid-base titration, in...

A downscaling in true titration based on a simple sequential injection analysis-lab-at-valve (SIA-LAV) has been proposed. A titrant solution was stepwise aspirated into a titration LAV chamber and a titration curve was obtained by monitoring the change in the solution color spectroscopically. This fully-automated SIA-LAV system required less volume...

A hyphenated sequential injection ion chromatography–flow injection analysis (SIIC–FIA) system is proposed for post column derivatization capable of using murexide, an unstable but commonly available reagent, for the determination of calcium and magnesium in a mixture. A short ion exchange column was modified from a 4.6 mm × 10 mm C18 monolithic gu...

We report here for the first time on the use of functional microemulsions in potentiometric assays to remove dilute interferences from solution when measuring high concentrations of analyte. The microemulsions are similarly formulated to the ion‐selective membrane used in the measurement and act as sacrificial material. They are here stabilized by...

A method for the determination of carbaryl in vegetable samples was developed employing peroxidase enzyme extracts from newly excised rubber tree bark strips as a catalyst. The solid phase extraction method QuEChERS was utilized for sample preparation followed by dispersive liquid-liquid microextraction (DLLME) to increase the concentration of the...

Simple simultaneous determination of iron and manganese by sequential injection spectrophotometry using astilbin extracted from Smilax china L. root is proposed. It is based on the kinetic difference of the complexation of the ions and astilbin. With a simple sequential injection system, the simultaneous determination can be performed at pH 10 and...

Anionic surfactant as sodium dodecyl sulfate (SDS) can be assayed by using methylene blue (MB). The ion-association of SDS-MB can be extracted solventless but sorbed on a specified polyurethane foam (PUF) monolithic rod, prepared in the lab by mixing polyether with methylene diphenyl diisocyanate (MDI). The blue product (the ion-association of SDS-...

Potassium ion concentration can be successfully determined volumetrically by moving the titration from a homogeneous phase to a two phase solvent system. This is because potassium can be readily complexed in a selective and thermodynamically stable manner by ionophores such as valinomycin. Previous work demonstrated the successful titration of pota...

A webcam camera as an alternative cost-effective colorimetric sensor for the simple dual electrochemical – colorimetric detection system is proposed. Performance test of the system was investigated through electrochemical and colorimetric behaviors of redox reactions of potassium ferrocyanide complex. Image processing with two color systems, RGB an...

Noodle based analytical devices are proposed for cost effective green chemical analysis. Two noodle based analytical platforms have been examined. Conditions for flow with laminar behaviors could be established. Detection may be via a webcam camera or a flatbed scanner. Acid-base reactions were chosen as a model study. The assays of acetic acid and...

A green and environmental friendly method with simple sequential injection spectrophotometry using natural reagent extract from pumpkin (Cucurbita moschata Decne) for determination of benzoyl peroxide (BPO) was developed. The maximum absorption of the yellow crude extract containing the β-carotene compound occurred at a wavelength of 450 nm. The ye...

A cost-effective assay for antioxidant using simple cotton thread combining paper based device with mobile phone detection has been investigated. Standard and sample solutions flow along a bunch of cotton thread treated with sodium hydroxide via microfluidic behaviors without external pumping. The analyte solution reacts with the reagents that have...

A simple, rapid and environmentally friendly sequential injection analysis system employing natural extract reagents was developed for the determination of acetic acid following an acid–base reaction in the presence of an indicator. Powdered lime and turmeric were utilized as the natural base and indicator, respectively. Mixing lime and turmeric pr...

Thai local plants known as banana stalk, banana blossom, banana, sugar-cane, oroxylum indicum fruit, sesbania grandiflora fruit, and pigeon pea fruit were utilized for screening peroxidase enzyme to replace costly horseradish peroxidase in the hydrogen peroxide assay. The highest peroxidase activity was found in banana stalk extracted solution. The...

A cost-effective and environmentally friendly approach using a simple sequential injection spectrophotometric system with a non-synthetic reagent from plant extracts was proposed for a green analytical-chemistry methodology. The crude aqueous extracts from heartwood of Ceasalpinia sappan Linn. in acetate buffer pH 5.5 were utilized as an alternativ...

Modern Information Technology (IT) and communications equipment (mobiles phones, scanners, etc) may all be used as image capture devices for paper-based colorimetric analysis. This paper evaluates the use of a mobile phone, a webcam, a flatbed scanner and a handheld scanner as image capture devices for colorimetric determination of reactive phospha...

A simple, rapid, and sensitive spectrophotometric method for the determination of benzoyl peroxide (BPO) in wheat flour samples was developed. The detection principle is based on BPO reacted with 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) to obtain a blue-green colored product that was detected at 415 nm by spectrophotometry. The...

The Chiang Mai University chemistry department celebrated the university's fiftieth anniversary with a one-day symposium on 14 January 2015, arranged by Professor Kate Grudpan, who contributed to the launch of the first PhD program in analytical chemistry in Thailand and was the first Professor of Analytical Chemistry in the country. The symposium,...

This paper reviews the development and recent use of everyday communications and IT equipment (mobile phones, digital cameras, scanners, webcams, etc) as detection devices for colorimetric chemistries. Such devices can readily be applied for visible detection using reaction formats such as microfluidic paper based analytical devices (µPADs), indica...

A sensitive, precise and reliable flow-batch method for the determination of aluminium (Al) was developed using a sequential injection-monosegmented flow system incorporating a mixing chamber unit. Eriochrome cyanine R (ECR) was used as a chromogenic reagent in the presence of N,N-dodecyltrimethylammonium bromide (DTAB). The Al-ECR complex at pH 6...

A mobile drop based approach was utilized for the conductometric determination of aqueous ammonium ion. A liquid drop was manipulated by gravity to remain or move out of a conductivity measurement zone located on a hydrophobic path. A dilute sulfuric acid drop functioned as a micro gas absorber. Gaseous NH3 was liberated from a sample containing NH...

A novel four-channel simultaneous injection effective mixing flow analysis (SIEMA) system has been assembled for successive determination of bilirubin and creatinine in urinary samples. The chemical variables and physical parameters in the flow system were optimized for the enhancement of successive analytical performances. The interferences from u...

A hydrodynamic sequential injection system was proposed for the determination of phosphate and silicate in wastewater and fish pond water samples. It was based on the molybdenum blue method with spectrophotometric measurement at 710 nm. Stopped-flow procedure was applied in order to increase the reaction time. Two calibration graphs, one for the de...

The evaluation and validation of a new low-cost microfluidic paper-based analytical device (μPAD) for the determination of reactive phosphate in soil solution is described. This device allows up to 15 replicate measurements of reactive phosphate on one credit card-sized device and requires only a desktop or hand scanner for signal detection and qua...

The sorption isotherms of newly available zeolites and two soil samples for heavy metal ions of Pb, Cu and Cd have been investigated. Experimental measurements have been made on the batch sorption of heavy metal ions from respective solutions using a single sample. All metal ions concentration in solutions of both initial and equilibrium condition...

Miniaturized coulometric titration in a liquid drop has been investigated. Assays of ascorbic acid and thiosulfate with iodine titration were chosen as models. Constant volumes of falling liquid drops containing sample or reagent are manipulated via gravimetrical force to move along a slope hydrophobic path and directed to stop or to move out from...

This review focuses on the developments of the various parts of instrumentation and the operation of low to medium pressure flow injection and sequential injection chromatography (FIC and SIC) systems. The report and discussion include solution delivery system, separation column, flow cell and detector, mobile phase management, and online sample pr...

A precise, accurate, and reliable flow-batch spectrophotometric method for the determination of selenium (IV) was developed using o-phenylenediamine as a reagent with a sequential injection monosegmented flow system incorporating a simple heating unit. The reaction zones of selenium(IV) and o-phenylenediamine were mixed and heated in a chamber at 6...

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 t...