Colorimetric Analysis

In this paper, colorimetric analysis for biochemical samples has been realized, by developing an easy-to-use smartphone colorimetric sensing android application that can measure the molar concentration of the biochemical liquid analyte. The designed application can be used for on-site testing and measurement. We examined three different biochemical materials with the application after preparation with five different concentrations and testing in laboratory settings, namely glucose, triglycerides, and urea. Our results showed that for glucose triglycerides, and urea the absorbance and transmittance regression coefficient (R 2) for the colorimetric sensing application were 0.9825, and 0.9899; 0.9405 and 0.9502; 0.9431 and 0.8597, respectively. While for the spectrophotometer measurement the (R 2) values were 0.9973 @560 nm and 0.9793 @600 nm; 0.952 @620 nm and 0.9364 @410 nm; 0.9948 @570 nm and 0.9827 @530 nm, respectively. The novelty of our study lies in the accurate prediction of multiple biochemical materials concentrations in various lightning effects, reducing the measurement time in an easy-to-use portable environment without the need for internet access, also tackling various issues that arise in the traditional measurements like power consumption, heating, and calibration. The ability to convey multiple tasks, prediction of concentration, measurement of both absorbance and transmittance, with error estimation charts and (R 2) values reporting within the colorimetric sensing application as far as our knowledge there has not been any application that can provide all the capabilities of our application.

"En este trabajo se presentó la extracción de aceite esencial y pectina a partir dela cascara de naranja (Citrus sinensis) como un proceso integral. Se realizó el proceso de extracción utilizando un simulador comercial adaptandose al proceso real. Se realizaron pruebas experimentales con un kilogramo de cáscara de naranja procesado a las mismas condiciones de la simulación con el fin de comparar los rendimientos obtenidos, logrando una concordancia aceptable. Posteriormente se escaló el proceso a una tonelada. Como resultado no solo se demuestran las ventajas del proceso integral, sino también la posibilidad de su implementación a nivel industrial. Se concluye ademas que las técnicas de simulación son una herramienta poderosa que permite minimizar tiempo,costos y experimentación en el diseño de procesos como los de extracción de aceite esencial y pectina"

Inorganic pigment of Co-Spinel was
synthesized by ultrasonic assisted co-precipitation method at different ultrasonic-treatment temperatures. The effect of ultrasonic treatment on reaction mechanism is also detailed. The colour analyses results indicated that the lowest b* value of -41.31 was observed at the ultrasonic treatment of 50°C. The synthesized bright blue powders were identified as Cobalt Aluminate Oxide (CoAl2O4, powder diffraction file number of 00-044-0160) in X-Ray diffraction (XRD) analyses. The colour
of synthesized compound was proved by adsorption peaks at the wavelengths of 550, 610 and 645 nm in UVVis spectroscopy (UV) results. The experimental results showed that spinels could be synthesized at higher crystallinity features by the use of ultrasonic treatment.

A novel Schiff base moiety 1 was synthesized and characterized by FT-IR, NMR and HRMS. The selectivity and sensitivity of 1 toward Cu 2+ ions was investigated by colorimetric, UV-vis, electrochemical, proton NMR experiments. It exhibits highly selective and sensitive recognition toward Cu 2+ ion over other metal ions in a wide pH range. The complex formed between 1 and Cu 2+ was found to be 1:1 stoichiometry with an association constant of 1.0 × 10 6 M −1 .

A series of rhodamine derivatives L1-L3 have been prepared and characterized by IR, 1H-NMR, 13C-NMR and ESI-MS. These compounds exhibited selective and sensitive "turn-on" fluorescent and colorimetric responses to Al3+ in methanol. Upon the addition of Al(III), the spiro ring was opened and a metal-probe complex was formed in a 1:1 stoichiometry, as was further confirmed by ESI-MS spectroscopy. The chemo-dosimeters L1-L3 exhibited good binding constants and low detection limits towards Al(III). We also successfully demonstrate the reversibility of the metal to ligand complexation (opened ring to spirolactam ring).

Two new highly selective colorimetric and fluoregenic aminopyridine Schiff bases (L1 and L2) were synthesized by simple refluxing method and characterised via standard NMR and HRMS techniques. Its excellent metal sensing abilities explored on absorbance and fluorescence spectroscopy. The recognition colorimertric sensing behavior of probes L1 and L2 towards Ni(II), Zn(II), Fe(III) and UO 2 (II) ions were carefully investigated with different aspects of sensing behavior such as sensitivity, binding constant , stoichiometry, pH range and interference effect. Moreover, L1 and L2 also displayed excellent " off-on " fluoregenic selectivity with Zn(II). The results revealed that the sensors provided colorimetric and fluoregenic sensing excellent response with low limit of detection, under neutral conditions.

We developed a simple method for the detection of platelet-derived growth factors (PDGFs) based on base stacking effect coupled with an unmodified gold nanoparticle (AuNP) indicator. In the absence of a target, an aptamer probe and a capture probe stably co-exist in a solution, as it is difficult to sustain an interaction between both these probes due to the short 8 bp duplex. However, when a target protein binds to the aptamer probe, the strong base stacking effect can lead to a favorable and stable interaction between the aptamer and capture probes. Hence, the capture probe dissociates from the AuNP surfaces, inducing AuNP aggregation. Compared with other AuNP-based aptasensors for PDGFs, using this base stacking effect can overcome a structured-aptamer method's limitation of requiring thiolated-aptamermodified AuNPs. Under optimal detection conditions, this label-free colorimetric sensor could detect PDGFs down to 6 nM with high selectivity in the presence of other interferring proteins. This simple detection approach provides viable methods for a structured-aptamer sensing protocol.

Pigment composites were obtained by adsorption of 9-aminoacridine and C.I. Mordant Red 11 onto silica supports which were both unmodified and also modified with N-2-(aminoethyl)-3-aminopropyltrimethoxysilane. The silica supports and pigment composites were characterised using particle size and polydispersity index, particle morphology and the presence of agglomerates, as well as sedimentation profile, water wettability and colorimetric parameters. The extent of silica surface coverage with each dye was determined on the basis of elemental analysis. The presence of functional groups on the silica support and the pigment composites was confirmed using FT-IR.

The drying kinetics of (Moringa Oleifera) leaves was investigated at different oven drying temperatures (40, 50 and 60 °C) using
an established drying mathematical model. The experimental drying data of moringa leaves on the basis of reduced chi-square
(χ
2
) and coefficient of determination (R2
), the mathematical model exposed the best fit to the drying curves. The values of
coefficient of determination (R2
) and reduced chi-square (χ2
) at 50 °C temperature was (0.998 to 0.999) and (0.009 to 0.0002)
respectively. Oven dry at 40 °C reveled optimum colour values.

Long-term monitoring (LTM) of remediated sites can be required on a quarterly basis for 30 or more years before site closure, with costs for sample collection, shipment, and analysis at an offsite fixed laboratory contributing 50 to 75 percent of the total expense. Cost-effective sampling techniques and field analysis could substantially reduce these costs. This technical report identifies and describes proven and promising sampling devices and onsite analytical instrumentation that potentially could be used now for LTM of ordnance-related compounds in groundwater. Instrumentation that generates data which can be used for regulatory decisions must be sufficiently sensitive to detect analytes of concern at action levels and must have excellent precision and accuracy to meet data quality requirements. Instrumentation for LTM must provide rigorous qualitative as well as quantitative identifications. The following general categories of field analytical technologies applicable to volatile organic chemicals and organic ordnance-related chemicals are included in this report: water quality monitors associated with low-flow purge techniques, discrete interval samplers, immunoassay for detection of explosives, gas chromatography with liquid compatible inlets, mass spectrometry with liquid compatible inlets, ion mobility spectrometry with liquid compatible inlets, chemical sensors, and colorimetric technologies. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. Preface The Environmental Laboratory (EL) of the U.S. Army Engineer Research and Development Center (ERDC) prepared this report, which was sponsored by the Long-Term Monitoring Focus Area of the Environmental Quality and Technology Program. The Principal Investigator was Dr. Denise K. MacMillan, Environmental Chemistry Branch (ECB), Environmental Processes and Engineering Division (EPED), EL, Omaha, NE. Mr. David E. Splichal performed surveys of the environmental instrumentation market and project personnel.

This work describes the first use of a portable centrifugal microfluidic analysis system (CMAS) for on-site lab-on-a-disc water quality monitoring. The centrifugal microfluidic platform designed for the detection of nitrite in multiple water samples incorporates photo-switchable microvalves, which are easily controlled using white light irradiation. Calibration of the system resulted in a linear response that obeys the Beer-Lambert Law. A very good correlation between the results obtained using the CMAS device and a standard UV-Vis spectrophotometer was obtained.

O uso da massa (g) ou do volume (cm³) como medida da quantidade de solo para determinação do teor de C orgânico do solo (COS), bem como a utilização de diferentes métodos de determinações analíticas empregados para essa mesma finalidade, pode alterar diretamente a interpretação dos resultados. Este trabalho teve como objetivo comparar os métodos colorimétricos e titulométricos de determinação de matéria orgânica em três solos com diferentes texturas, tomando-se as amostras por massa (pesagem) e por volume (cachimbagem). Houve variação no teor de COS entre os métodos estudados para um mesmo solo. O uso da massa e do volume alterou diretamente a interpretação dos teores de matéria orgânica no solo. Há variações nos métodos de determinação de COS entre solos de diferentes texturas.

Chlorpyrifos (CPF), an organophosphate insecticide, is widely identified in fruit juices. In this study, a novel molecularly imprinted polymers-surface-enhanced Raman spectroscopy (MIPs-SERS)/colorimetric dual sensor was developed to determinate CPF in apple juice. MIPs were synthesized using bulk poly-merization to rapidly and selectively adsorb and separate CPF from apple juice. A colorimetric method was developed based upon color changes of synthesized silver nanoparticles (AgNPs) by interacting with CPF, while SERS spectra were directly collected by illuminating the aggregated AgNPs with Raman laser. Colorimetric method rapidly screened and semi-quantified CPF in apple juice ≥5 mg L −1 by naked eye, or accurately quantified CPF in apple juice ranging 0.1–10 mg L −1 by UV–vis spectroscopy. Principle component analysis and partial least-squares regression models (RMSEC = 0.0453, R 2-C = 0.9885) validated using SERS to further quantify CPF in apple juice at extremely low concentration (0.01 mg L −1). This MIPs-SERS/colorimetric dual sensor can rapidly (<25 min), accurately, and cost-efficiently determine CPF in apple juice and meet the worldwide regulation of maximum residue limit.

Rapid and inexpensive assays for drug susceptibility testing (DST) of Mycobacterium tuberculosis (MTB) are urgently required especially in developing countries where tuberculosis cases are prevalent. In response to this necessity, a direct microplate-based colorimetric assay which excludes the use of pre-testing culture isolate was evaluated. MTB susceptibility to the first line anti-tuberculosis drugs was tested directly on sputum specimens using tetrazolium microplate assay (TEMA) method and the sensitivity, specificity, accuracy as well as mean turnaround time of TEMA were compared to the standard absolute concentration method (ACM). TEMA was performed on 41 acid fast bacilli (AFB) positive sputum specimens by direct inoculation of the processed specimens into the microplate wells containing serial-diluted first line anti-tuberculosis drugs using tetrazolium dye as growth indicator. Indirect TEMA was performed on MTB isolates of the corresponding samples. The minimum inhibitory concentrations (MICs) of isoniazid (INH), rifampicin (RMP), ethambutol (EMB) and streptomycin (SM) were obtained for direct and indirect TEMA with reference to the absolute concentration method (ACM). After establishing the breakpoint MIC of each drug using receiver operating characteristics (ROC) curve, reliable results from direct TEMA were obtained for INH and SM, with excellent levels of sensitivity, specificity, and accuracy (more than 90%). The predictive values for susceptibility were 100% for INH, EMB and SM as well as 96% for RMP. A shorter mean turnaround time of 14 days was observed for direct TEMA (P < 0.05). Thus direct TEMA is potentially rapid, reliable and inexpensive DST screening method of MTB in countries with high prevalence rates of drug resistance tuberculosis.

Thiacalix[4]arene based imino receptors 4–5 carrying azophenol appendage have been synthesized and studied for their binding abilities towards different metal ions (Li+, Na+, K+, Cd2+, Ni2+, Cu2+, Zn2+, Ag+, Pb2+ and Hg2+). Receptor 4 showed selective chromogenic sensing for Cu2+ ions in mixed aqueous conditions (THF:H2O, 9:1 v/v).Thiacalix[4]arene based imino receptors 4–5 carrying azophenol appendage have been synthesized and studied for their binding abilities towards different metal ions (Li+, Na+, K+, Cd2+, Ni2+, Cu2+, Zn2+, Ag+, Pb2+ and Hg2+). Receptor 4 showed selective chromogenic sensing for Cu2+ ions in mixed aqueous conditions (THF:H2O, 9:1 v/v).

Spectral measurements have been carried out on polished stone slabs to show the accuracy of theoretical colorimetric calculations on perceptual differences of color appearance under various standard illuminations. Effects of the different spectral characteristics of the light source on colorization of the samples have been also studied to analyze the changes of color sensation on the samples in connection with the changes on the type of the illuminating source. Solar light (Standard Illuminant D65), basic incandescent source (Standard Illuminant A) and a basic fluorescent source (Standard Illuminant F11) have been tested on Tardos red limestone, Siklós green limestone, Carrara white and gray marbles and diorite samples. Colorizing effects of the examined illuminations are compared to Standard Illuminant E-the theoretically perfect white source.

Deep marine successions of early Campanian age from DSDP (Deep Sea Drilling Project) site 516F drilled at low paleolatitudes in the South Atlantic reveal distinct sub-Milankovitch variability in addition to precession, obliquity and eccentricity-related variations. Elemental abundance ratios point to a similar climatic origin for these variations and exclude a quadripartite structure as an explanation for the inferred semi-precession cyclicity in the magnetic susceptibility (MS) signal as observed in the Mediterranean Neogene for precession-related cycles. However, semi-precession cycles as suggested by previous work are likely an artifact reflecting the first harmonic of the precession signal. The sub-Milankovitch variability, especially in MS, is best approximated by a ∼ 7 kyr cycle as shown by spectral analysis and bandpass filtering. The presence of sub-Milankovitch cycles with a period similar to that of Heinrich events of the last glacial cycle is consistent with linking the latter to low-latitude climate change caused by a non-linear response to precession-induced variations in insolation between the tropics.

An efficient colorimetric and fluorescent chemodosimeter for Fe 3+ ions has been developed. The visual and fluorescent behaviors of the receptor toward various metal ions were investigated. The receptor shows exclusive response toward Fe 3+ ions and also distinguishes Fe 3+ from other cations by color change and unusual fluorescence enhancement in aqueous solution (DMSO/H 2 O = 4/1, v/v). Thus, the receptor can be used as a colorimetric and fluorescent sensor for the determination of Fe 3+ ion. The visual color detection limit and the fluorescence detection limit of the receptor towards Fe 3+ are (1.42 ± 0.01) × 10 -6 M and (7.57 ± 0.04) × 10 -8 M, respectively. The fluorescence microscopy experiments showed that the receptor is efficient for detection of Fe 3+ in vitro, developing a good image of the biological organelles. The sensing mechanism is proven to be a hydrolysis process.

The incorporation of new methods of heritage analysis belonging to other branches of science is currently providing very useful tools for the examination of preservation products. This paper outlines the use of spectral images as an alternative to traditional colorimetry measurements carried out with a spectrophotometer for the evaluation of color changes produced by consolidation treatments applied on polychromed plasterwork. Thus, for this investigation we used a total of 18 plaster test specimens which reproduce the techniques and materials present in plasterwork from the medieval era, on which a selection of six currently-used consolidants was applied. By doing this, we have proved that the use of this method over traditional colorimetry has several advantages, such as the analysis of spatial homogeneity or obtaining colorimetric data of the entire scanned surface.

The Institut Cartogràfic de Catalunya (ICC) operates a Digital Metric Camera (DMC), manufactured by Z/Imaging. It supports the simultaneous capture of panchromatic, RGB colour and near-infrared images. One of the most important ICC products is the Catalonia orthophotomap series. This product is intended to depict the territory as realistically as possible. With this aim, ICC is developing a project to obtain genuine colours in the photographic products produced with the DMC camera and this paper contains some preliminary results. Since an absolute radiometric calibration of the DMC is not available yet, this is accomplished through simultaneous images acquired with both DMC and a Compact Airborne Spectral Imager (CASI) also operated by ICC. These images are used to locate common areas imaged in similar geometrical conditions, and then a linear relationship between Digital Numbers (DN) from DMC and radiance values of a CASI image emulating DMC bands is calculated. To improve the colour of the DMC products, a colorimetric calibration based on polynomial transformations has been developed. This transformation allows changing from DMC-RGB space to a sRGB space that is based on CIE-XYZ colour space. Airborne ICC-CASI images acquired with a Cessna Caravan B20 over Banyoles (Spain) in 2005 were used to test the methodology. The comparison between the training colours and the ones obtained after colorimetric calibration yield differences in 8bit DN that range from 4 to 36 DN with a mean value of 12 DN. The effect was also visually analyzed on different subsets of images that include agriculture areas, urban landscape and a natural water layer. Finally, it was found that the application of both calibrations to the DMC images results in a consistent colour combinations for all the analyzed subsets.

The Institut Cartografic de Catalunya (ICC) operates a digital metric camera (DMC), manufactured by Z/Imaging. It supports the simultaneous capture of panchromatic, RGB colour and near-infrared images. One of the most important ICC products is the Catalonia orthophotomap series. This product is intended to depict the territory as realistically as possible. With this aim, ICC is developing a project to obtain genuine colours in the photographic products produced with the DMC camera and this paper contains some preliminary results. Since an absolute radiometric calibration of the DMC is not available yet, this is accomplished through simultaneous images acquired with both DMC and a compact airborne spectral imager (CASI) also operated by ICC. These images are used to locate common areas imaged in similar geometrical conditions, and then a linear relationship between digital numbers (DN) from DMC and radiance values of a CASI image emulating DMC bands is calculated. To improve the colo...

Medieval plasterwork currently faces preservation issues due to the lack of cohesion between their polychrome sections, which, if not adequately treated in time, cause the irretrievable loss of their original appearance. It is relatively frequent to observe how the plasterwork preserve only scarce remains of their original color appearance in monuments like the Alhambra, the Alcazar in Seville or in pieces stored in Archeological Museums all over the world. The loss of vividness in the color of the plasterwork has been caused mostly by exposure to humidity, aggressive cleaning agents or by superposed paint layers applied at a later period. In view of these facts, the main aim of this study is to determine the best consolidant of choice to fix and preserve medieval plasterwork, from a colorimetric perspective. A set of 48 plaster probes have been built and the polychromy has been applied according to the procedures and materials used in the mediaeval period. Each probe was 6.5 x 13 cm in size, and three different natural pigments have been applied on 16 probes each (natural azurite, cinnabar and lead red) with two different binders (animal glue and arabic gum). Figure 1 shows an instance of one of the probe series for lead red. In the study, the methodology used to evaluate the color changes induced by six different consolidants is presented, and the results analyzed. The consolidants are: ethyl silicate (Estel 1200, BE), ethyl silicate (Nanoestel, NE), acrylic resin (Paraloid® B72, PAB72), hydroxypropyl cellulose (Klucel®G, KL), polyvinyl butyral (Mowital® B60H, MW) and thermoplastic polymer (Aquazol®, AQ). Two factors have been analyzed in the preliminary results: uniformity of the applied pigments across probes, and effect of applying the consolidant on the probes, in average across the different pigments. For the first time to our knowledge, a hyperspectral imaging system (Resonon PikaL camera) has been used to measure the spectral reflectance of the probes before and after applying the consolidants. Using the spectral reflectance data, CIEDE00 color difference and two additional spectral difference metrics (Root-Mean-Square-Error or RMSE and Goodness-of-Fit coefficient or GFC) have been computed between corresponding probes to analyze the two factors mentioned above. Besides, changes in perceptual attributes like Lightness, Chroma and Hue have been studied using the CIELAB color coordinates of the samples. Figure 1. Left: Lead Red probes prepared for spectral reflectance measurement with the PikaL system (center). Right: CIEDE00 results comparing the probes before and after the consolidants have been applied, in average for the three pigments used. The results show that the least homogeneous pigment across probes is azurite, due to the effect of the grind size on the pigment obtained and the difficulty of the binding process. Also, the least homogeneous binder is arabic gum. Regarding the effect of applying the consolidant, the Klucel® is the agent that best preserves sample color, and Mowital®B60H is the consolidant which causes the most noticeable change in color in average across pigments. The use of a hyperspectral capture device will enable us to analyze the effect of the consolidant agent in the local spatial texture of the sample, which poses an additional advantage over traditional area-based color measurement devices. This methodology is also potentially valid to perform colorimetric quality assessments of other preservation actions for plasterworks, like cleaning and color reintegration operations.

The kinetics of Glucose oxidase (GOD) and Horseradish peroxidase (HRP) on a transparent Ion Jelly biopolymer has been investigated using a colorimetric assay of H2O2 with phenol-4-sulfonic acid and 4-aminoantipyrine, as color-generating precursors. The activity of GOD and HRP on the Ion Jelly biopolymer solid disk formed in the bottom of the well ELISA plate showed to be respectively 16 times and 13 times lower than in free sodium phosphate buffer. The storage stability at 4°C of the both immobilized enzymes showed that GOD can retain up to 70% of the initial activity after two weeks, where HRP retained 91% of its initial activity. The drop cast deposition of the transparent Ion Jelly biopolymer containing the two enzymes (GOD, HRP) and the color-generating precursors on filter paper allowed to demonstrate their applicability on colorimetric glucose detection.

Tri-organotin(IV) complexes of the triazolo-pyrimidine derivatives 4,5-dihydro-5-oxo-[1,2,4]triazolo-[1,5a]pyrimidine (5HtpO), 4,7-dihydro-5-methyl-7-oxo-[1,2,4]triazolo-[1,5a]pyrimidine (HmtpO), and 4,5,6,7-tetrahydro-5,7-dioxo-[1,2,4]triazolo-[1,5a]pyrimidine (H 2 tpO 2 ), and the diorganotin derivative n-Bu 2 Sn(tpO 2 ), were synthesized and characterized by means of infrared and 119 Sn Mö ssbauer spectroscopy. In all the complexes obtained the triazolopyrimidines act as multidentate ligands producing polymeric structures.

In this paper, we demonstrate for the first time the use of silver nanoparticles (AgNPs) for colorimetric ascorbic acid (AA) quantification in a paper-based sensor. This device is constituted by spot tests modified with AgNPs and silver ions bordered by a hydrophobic barrier which provides quantitative and fast analysis of AA. In addition, this device is employed as point-of-care monitoring using a unique drop of the sample. AgNPs paper-based sensor changed from light yellow to gray color after the addition of AA due to nanoparticle growth and clusters formation. The color intensities were altered as a function of AA concentration which were measured by either a scanner or a homemade portable transmittance colorimeter. Under the selected measurement conditions, results presented limit of detection which was comparable to analytical laboratory-based methodologies. In addition, the sensitivity of our sensor was comparable to the standard titration method when real samples were investigated.

A new simple and multifunctional fluorescent probe based on pyrene linked through an imine bond to a hydroxyphenol unit was synthesised, fully characterized and investigated in solution. Additionally, its behaviour in the presence of several ions (H þ , Zn 2þ , Cd 2þ , Cu 2þ , Ni 2þ , Pb 2þ , Fe 2þ , Hg 2þ and Al 3þ ) was investigated in CH 2 Cl 2 . It was found that the absorption spectra of probe 1 shows no differences for all ions titrations except in the presence of H þ and Hg 2þ where a new longer wavelength band becomes visible (inducing a colour change from yellow to orange and pink, respectively). In the emission, a blueshift and an enhancement of the fluorescence of the probe for all metal ions was observed with the exception of Al 3þ where no detectable changes could be observed. The probe was found to be selective for Hg 2þ ion at low concentrations (till one equivalent).

The main objective of this work was to test the performance of major formulas for assessment of small suprathreshold color differences in the blue region. The models examined include CIELAB color space based equations, including CIELAB, CIE94, CIEDE2000, CMC (l:c), BFD (l:c), and formulas based on more uniform color spaces, such as DIN99d, CAM02-SCD, CAM02-UCS, OSA-GP, and OSA-Eu in comparison against data obtained via visual assessments. For this purpose, a dataset around the CIE high-chroma blue color center, hereafter called NCSU-B2, was developed. The NCSU-B2 dataset comprised 65 textile substrates and a standard, with a mean ΔEab* color difference of 2.72, ranging from 0.54-5.72. Samples were visually assessed by 26 subjects against the reference gray scale in three separate trials with at least 24 h between assessments. A total of 5070 assessments were obtained. The standardized residual sum of squares (STRESS) index was used to examine the performance of various formulas for this dataset, as well as a previously developed NCSU-B1 low-chroma blue dataset [Color Res. Appl.36, 27, 2011], and blue centers from other established visual datasets. Results show that formulas based on more recent uniform color spaces provide better agreement with perceptual data compared with models based on CIELAB space.

... Ziadi a * , Gilles Bélanger a , Bernard Gagnon a &amp; Danielle Mongrain a pages 132-140. ... The extract was filtered using a no. 42 Whatman filter paper and stored at 4 °C until analysis. The ICP and the colorimetric method (Murphy and Riley 196214. Murphy, J. and Riley, JP 1962. ...

Long-term monitoring (LTM) of remediated sites can be required on a quarterly basis for 30 or more years before site closure, with costs for sample collection, shipment, and analysis at an offsite fixed laboratory contributing 50 to 75 percent of the total expense. Cost-effective sampling techniques and field analysis could substantially reduce these costs. This technical report identifies and describes proven and promising sampling devices and onsite analytical instrumentation that potentially could be used now for LTM of ordnance-related compounds in groundwater. Instrumentation that generates data which can be used for regulatory decisions must be sufficiently sensitive to detect analytes of concern at action levels and must have excellent precision and accuracy to meet data quality requirements. Instrumentation for LTM must provide rigorous qualitative as well as quantitative identifications. The following general categories of field analytical technologies applicable to volatile organic chemicals and organic ordnance-related chemicals are included in this report: water quality monitors associated with low-flow purge techniques, discrete interval samplers, immunoassay for detection of explosives, gas chromatography with liquid compatible inlets, mass spectrometry with liquid compatible inlets, ion mobility spectrometry with liquid compatible inlets, chemical sensors, and colorimetric technologies. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. Preface The Environmental Laboratory (EL) of the U.S. Army Engineer Research and Development Center (ERDC) prepared this report, which was sponsored by the Long-Term Monitoring Focus Area of the Environmental Quality and Technology Program. The Principal Investigator was Dr. Denise K. MacMillan, Environmental Chemistry Branch (ECB), Environmental Processes and Engineering Division (EPED), EL, Omaha, NE. Mr. David E. Splichal performed surveys of the environmental instrumentation market and project personnel.

O uso da massa (g) ou do volume (cm³) como medida da quantidade de solo para determinação do teor de C orgânico do solo (COS), bem como a utilização de diferentes métodos de determinações analíticas empregados para essa mesma finalidade, pode alterar diretamente a interpretação dos resultados. Este trabalho teve como objetivo comparar os métodos colorimétricos e titulométricos de determinação de matéria orgânica em três solos com diferentes texturas, tomando-se as amostras por massa (pesagem) e por volume (cachimbagem). Houve variação no teor de COS entre os métodos estudados para um mesmo solo. O uso da massa e do volume alterou diretamente a interpretação dos teores de matéria orgânica no solo. Há variações nos métodos de determinação de COS entre solos de diferentes texturas.

Molecular-based methods to monitor point mutations require special and expensive equipment unavailable in most hospitals. Colorimetric-based analysis is an ideal platform for K-ras codon 12 gene point mutations because it uses commonly found hospital equipment. The colorimetric assay is sensitive and specific, detecting mutated DNA levels as low as 1% in a wild-type background. Paired genomic DNA extracts of fixed tissue and cellular fractions of peripheral blood are more sensitive and accurate than unpaired samplings. This approach has the potential to improve K-ras point mutation scans as well as to detect micrometastases in circulating tumor cells.

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