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We built a clear micelle gel dosimeter with nanoclay. Jordan et al. reported that Laponite RD clay nanoparticles when added to radiochromic leucomalachite green micelle gels eliminate diffusion and increase the dose sensitivity by roughly ten folds. However, owing to the cloudiness of the sample, there was a problem in reading the optical computed tomography (CT). In this study, we constructed a nanoclay-added micelle gel dosimeter by changing the type of gelatin. As a result, in addition to yielding a clear gel and making the optical CT readable, diffusion and temporal stability were improved more than the gel without using nanoclay, and the dosimeter showed the same level of sensitivity and diffusion as the one based on Laponite-added micelle gel reported by Jordan et al.

In this work, a convenient, sensitive method for simultaneous monitoring of malachite green, leucomalachite green in tilapia samples was developed by ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The tilapia samples were extracted by acetonitrile, separated withacetonitrile-5mmol/L ammonium acetate as mobile phase, and then detected under ESI+ mode. The method showed a good linearity for all the analysts over the range of 0.1-100 μg kg-1 with r2≥0.998. And the detection limits both were 0.10 μg kg-1 for Malachite green and leucomalachite green. Tests for recovery were made by addition of standards at four different concentration levels (0.5, 2.0, 10.0, 20.0 μg kg-1) to the blank sample. The recoveries of the four spiked concentrations were ranged from 81.5% to 104%, with the relative standard deviations lower than 5%. The sensitivity, accuracy and precision of this method were able to meet the requirements for malachite green and leucomalachite green residue analysis.

Malachite green (MG) has an extensive use as a biocide in aquaculture industries throughout the world. It is found to be highly effective against protozoal and fungal infections, besides being used as colorant for textiles and coloring additives in packed foods and fish industries. Aquaculture industries have used MG for topical applications by bath or flush methods, without giving due attention to the fact that in topical application, the therapeutants might be absorbed systemically and may produce significant internal effects. The presence of nitrogen in the ring structure of MG makes it a very controversial compound as it poses risks to those who consume MG-exposed fishes; it also causes subsequent detrimental effects to the immune system by genotoxicity and carcinogenesis. Another concern arises due to progressive accumulation of leucomalachite green formed via biotransformation of MG in various tissues; it can enter mammalian cells through the food chain and poses high toxicity. Diverse treatment str...

Malachite green (MG) has been widely used in aquaculture to treat a number of microbial and parasitic diseases. It is currently banned in the EU because of the high cytotoxicity and carcinogenic activity, which is also shared by leucomalachite green (LMG), a reduced MG metabolite that can persist in fish tissues for months. There is scant information about the ability of either compound to interact with drug metabolizing enzymes in fish. Therefore we evaluated the in vitro effects of MG and LMG (25, 50 and 100μM) on some DMEs and glutathione (GSH) content in rainbow trout liver subfractions. LMG did not affect any of the examined parameters. In contrast, MG proved to deplete GSH and to depress to a various extent the activities of NAD(P)H cytochrome c reductase, 7-ethoxycoumarin O-deethylase, 1-naphthol uridindiphosphoglucuronyl-transferase and maximally those of 7-ethoxyresorufin O-deethylase (EROD) and glutathione S-transferase (GST) accepting 1-chloro2,4-dinitrobenzene (CDNB) as substrate. The inhibition mechanisms of EROD and GST were investigated by means of non-linear Michaelis-Menten kinetics and Lineweaver-Burk plots using 0.175-8μM MG. The calculated IC50 for EROD was 7.1μM, and the inhibition appeared to be competitive (Ki 2.78±0.24μM). In the case of GST, the calculated IC50 was 0.53μM. The inhibition was best described as competitive toward GSH (Ki 0.39±0.02μM) and of mixed-type toward CDNB (Ki 0.64±0.06μM). Our findings indicate that, contrary to LMG, MG behaves as a relatively strong inhibitor of certain liver DMEs and can reversibly bind GSH.

A new biomimetic sensor for leucomalachite green host-guest interactions and potentiometric transduction is presented. The artificial host was imprinted in methacrylic acid or acrylamido-2-methyl-1-propanesulfonic acid-based polymers. Molecularly imprinted particles were dispersed in 2-nitrophenyloctyl ether and trapped in poly(vinyl chloride). The potentiometric sensors exhibited a near-Nernstianresponse in steady state evaluations, with slopes and detection limits ranging from 45.8 to 81.2 mVdecade-1and 0.28 to 1.01 μg mL-1, respectively. They were independent from the pH of test solutions within 3 to 5. Good selectivity was observed towards drugs that may contaminate water near fish cultures, such as oxycycline, doxycycline, enrofloxacin, trimethoprim, creatinine, chloramphenicol, and dopamine. The sensors were successfully applied to field monitoring of leucomalachite green in river samples. The method offered the advantages of simplicity, accuracy, applicability to colored and turbid samples, and automation feasibility.

Electrochemiluminescence (ECL) of Ru(bpy)32+ and bimetallic ruthenium tris-bipyridyl complex [(bpy)2Ru(bpy)(CH2)8(bpy)Ru(bpy)2]4+ (1) at a gold electrode has been employed for the determination of malachite green (MG) in this paper. For Ru(bpy)32+, a linear response (R2 = 0.9992) was obtained over a MG concentration range of 1.0 × 10−8 to 1.0 × 10−5 M, with a remarkable detection limit of 1.0 × 10−8 M in a pH 10 borate buffer. The detection limit was further decreased to 1.0 × 10−12 M for the bimetallic ruthenium complex 1. Meanwhile, leucomalachite green (LMG) was detected and the same detection limit was reached. Which is much lower compared to the other detection methods. To check its applicability, the proposed method was employed in the determination of MG/LMG added into a fishpond water sample, and good reproducibility and stability were achieved. These results show that it will be possible to develop an ECL detection method for MG/LMG.

A new multianalyte immunoassay was designed to screen furaltadone metabolite 5-morpholinomethyl-3-amino-2-oxazolidone (AMOZ), malachite green (MG), and leucomalachite green (LMG) in aquatic products using a bispecific monoclonal antibody (BsMAb). Gradient drug mutagenesis methods were separately used to prepare an anti-3-nitrobenzaldehyde-derivatized AMOZ (3-NPAMOZ) hybridoma cell line that was hypoxanthine-guanine-phosphoribosyltransferase (HGRPT) deficient and an anti-LMG hybridoma cell line that was thymidine kinase (TK) deficient. BsMAb recognizing 3-NPAMOZ and LMG was generated using hybrid-hybridomas of HGRPT and TK deficient cell lines. For AMOZ and LMG, respectively, the BsMAb-based indirect competitive ELSIA (ic-ELISA) values of 1.7 ng/mL and 45.3 ng/mL and detection limits of 0.2 ng/mL and 4.8 ng/mL. To establish the ic-ELISA, 3-NPAMOZ derivatized from AMOZ with 3-nitrobenzaldehyde and LMG reduced from MG by potassium borohydride was recognized by BsMAb. Recoveries of AMOZ, MG, and LMG in aquatic products were satisfactory and correlated with HPLC analysis. Thus, the multianalyte ic-ELISA is suitable for rapid quantification of AMOZ, MG, and LMG in aquatic products.

A simple method using LC/MS/MS was developed and validated to determine residues of malachite green (MG) and leucomalachite green (LMG) in fish fillet. A modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) technique was used to perform the sample preparation. The optimal extraction and cleanup conditions were established using an experimental design. The validation parameters obtained to determine both MG and LMG complied with the requirements established by regulatory agencies for the presence of such substances in fish, which establish that the method must attain, at least, a minimum required performance limit of 2 ng/g. The accuracy values ranged between 95 and 107%, and the precision values were lower than 11.2%. The method was used in the analysis of tilapia samples (n = 20) commercialized in Campinas, SP, Brazil. None of the samples presented detectable levels of MG or LMG residues.

Aquaculture in Brazil has shown expressive development since the 1990s with growth rates superior to those of cattle and poultry. In order to achieve greater productivity, intensive fish cultivation systems are employed, which can cause greater susceptibility to diseases caused by viruses, bacteria, fungi, and parasites. The reduced availability of veterinary medications approved for use in aquaculture in Brazil has lead fish farmers to the indiscriminate use of several chemical substances with antimicrobial activity, such as the dye malachite green (MG). As a result of this use, residues of MG and its main biotransformation product, leucomalachite green (LMG), may be present in fish available for consumption. The presence of residues of these compounds represents a risk to human health due to their toxicity, as well as a potential impact on the environment, and could also raise barriers for commercialization in the country and for exportation. The objective of this review is to provide the context and evidence of the use of MG in aquaculture and of its toxicological and legislative aspects. A review of the analytical methods used to determine MG residues in fish, with emphasis on mass spectrometry, is also presented.

Leucomalachite green (LMG) is mutagenic and produces DNA-adducts in vivo, and is carcinogenic in rodent bioassays. Dose-response modelling of the data for hepatocellular adenomas and carcinomas in female mice gave a BMDL10 of 20 mg/kg-bw/day. Limited data are available on the concentrations present in fish for human consumption. Human exposure estimates assumed that all consumed fish is contaminated with LMG. The calculated MoEs were 4,000,000 and 400,000 respectively for average and high exposure estimates.

Malachite green (MG), a triphenylmethane dye, is carcinogenic, mutagenic, teratogenic, a respiratory toxin, and causes chromosomal fractures. It is not permitted for use as an aquaculture veterinary drug in a number of countries. Sensitive extraction methods for MG and leucomalachite green (LMG), which have long residence times in fish tissues, were developed. For LMG, the average recovery of liquid extraction (LE) ranged from 41.71 (yellowtail) to 71.60% (snakehead); the recovery of liquid-liquid extraction (LLE) was between 67.68 (yellowtail) and 83.68% (snakehead); and the average recovery of solid-phase extraction (SPE) ranged from 84.16 (yellowtail) to 92.92% (shrimp). The recovery of MG was less than 30% with SPE. However, the dye is found primarily as the colorless reduced leuco form in fish tissues.

The influence of atmospheric oxygen on the efficiency of the PRESAGE® dosimeter was investigated. Batches of PRESAGE® and reporting system solution were deoxygenated using nitrogen and compared to similar batches that were exposed to atmospheric oxygen during fabrication. The overall results show little influence of oxygen on the characteristics of PRESAGE® with the radical initiator oxidizing the leucomalachite green in the presence of oxygen. However, when deoxygenating the reporting system the sensitivity to radiation dose increased by 30% compared to the non-deoxygenated system. A slight improvement in sensitivity (5%) was achieved by deoxygenating the PRESAGE® precursors prior to casting. The results suggest that the solid polyurethane matrix is not permeable to atmospheric oxygen. In addition, there were no observed changes in the dose linearity, absorption spectrum and post-response photofading characteristics of PRESAGE® under the conditions investigated. Refereed/Peer-reviewed

Colourless polystyrene-leucomalachite green (PS-LMG) thick films containing a suitable chloroalkane were prepared by a fast and facile casting method, and were investigated for their radio chromic response behavior under the influence of 1.25 MeV γ-radiation. Their gamma response was studied in the 0.05 kGy to 10 kGy range to evaluate their suitability for potential use as the dosimeter in the radiation processing industries. The films were found to undergo a visibly distinct green coloration in the studied range, with the colour intensity increasing with an increase in the total dose. The radiochromic response of these films when investigated as a function of film thickness showed that the colour development as well as the linearity of the response was markedly affected by the thickness of the films. The effect of dye loading and the chloroalkane concentration on the radiochromic response of these films were also investigated. Depending upon the film thickness and reactant concentrations, the films were found to be capable of visually detecting gamma radiation doses as low as few tens of grays.

To develop a more sensitive immunoassay for malachite green (MG) and leucomalachite green (LMG), we identified the immunocomplex binding phage-borne peptides for use in the noncompetitive phage anti-immunocomplex assay (PHAIA). An anti-LMG monoclonal antibody (mAb) was used to select immunocomplex binding peptides from a circular random eight-amino-acid phage-displayed library. After three rounds of panning-elution, five peptides that bound the LMG-mAb immunocomplex were obtained. One of the phage-borne peptide clones that resulted in an assay with the highest sensitivity was chosen for further research. The concentration of LMG producing 50% of the saturated signal and the limit of detection of the assay were 7.02 and 0.55 ng/mL, respectively, with a linear range of 1.35 to 21.56 ng/mL. The PHAIA based on the same antibody was 16 times more sensitive compared to the competitive immunoassay. PHAIA was used to analyze LMG, MG, and two mixtures of spiked fish samples, with validation by high-performance liquid chromatography (HPLC) with fluorescence detector. Results showed a good correlation (R(2)LMG = 0.9841; R(2)MG = 0.993; R(2)Mixture = 0.9903) between the data of PHAIA and HPLC, thus the assay was an efficient method for monitoring food safety.

It is the responsibility of the forensic specialist to have knowledge of available resources and be able to use these resources to detect, collect and preserve physical evidence during an investigation. The objective of this article is to make members of the forensic law enforcement discipline aware of some of the procedures available to them to enhance blood prints found at a scene or on an exhibit. The Royal Canadian Mounted Police (RCMP) presently uses six bloodstain enhancement techniques: Amido Black, Crowle's Double Stain, Hungarian Red, Leucomalachite Green, Luminol, and forensic light sources. For the purpose of this experiment only the first four mentioned were used. Luminol and the forensic light sources will be discussed in the conclusion of this report.

In this study we carry out a comparison between the commercially available leucomalachite green (LMG) dye and three newly synthesised derivatives (with either methoxy, chloro or bromo substituents) incorporated into the PRESAGE dosimeter to determine their effect on the sensitivity and post- response photostability of the dosimeter. In addition, the influence of the new LMG derivatives on the basic radiological properties of the PRESAGEs dosimeter was also investigated. The dosimeters were prepared in spectrophotometric cuvettes, irradiated with a 6 MV X-ray beam, and the change in optical density of each dosimeter was measured using a spectrophotometer. For all of the new LMG derivatives investigated, the sensitivity of the resulting dosimeters to radiation dose increased significantly relative to the unmodified LMG dosimeter, and was dependent on the type of LMG derivative used, with the bromo substituted derivative showing the highest increase in sensitivity (450%), followed by chloro and methoxy substituted derivatives (340 and 200%, respectively). Overall, the new LMG derivatives had only a minimal influence on the radiological properties of the PRESAGE dosimeter, with the exception of the bromo substituted LMG, which increased the effective atomic number (Zeff) of the dosimeter by 9%. All of the LMG dyes investigated showed similar post-response photostability characteristics, with the methoxy substituted LMG showing a slight improvement in post-response photoretention. Refereed/Peer-reviewed

東京海洋大学博士学位論文 平成24年度(2012) 応用生命科学 課程博士 甲第280号, 指導教員: 舞田正志, 全文公表年月日: 2018-07-06

By a newly developed gel-preparation method using binary aqueous mixed solvents, such as a methanol–water or an ethanol–water mixture, before gelation as a sol solvent and after gelation as a gel environmental solvent, stable gel colors and xerogel colors of calcium alginate (Ca alg.) including photosensitive chlorophyll a (chl.a) were obtained. Ca alg. gel containing leucomalachite green (leuco-M) was made by using the same mixed solvents; after gelation by immersion in mixed solvents or in an acidic solution of various pH values, color development was investigated under ultraviolet irradiation (365 nm). From gel rupture stress measurements, absorption spectral measurements, and an X-ray diffraction study, etc., it was found that such gel-color stability mainly depends on the conformational stability of the host gel.

An electrochemiluminescence (ECL) inhibition method combined with molecularly imprinted solid phase extraction (MISPE) was developed for quantitative determination of malachite green (MG) residues in fish. It was found that MG could strongly inhibit the ECL signal of luminol. Under the optimized conditions, the quenched ECL intensity versus the logarithm of the concentration of MG was in good linear relationship over a concentration range from 20 to 5000 ppt. The method detection limit was found to be about 6 ppt. Molecularly imprinted polymers (MIPs) were synthesized as solid phase extraction (SPE) sorbents, and MISPE was used for the selective extraction and purification of MG. By carrying out the oxidation reaction with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), which could convert leucomalachite green (LMG) into MG, this method was successfully applied to determine MG residues in fish. A possible mechanism for the quenching effects of MG on luminol was also proposed.

High-speed surgical instruments and electric coagulator devices produce contaminated particles and aerosols. This study aimed to investigate the presence of blood-contaminated aerosol in a class 6 and 7 (ISO14644-1) operating room environment. Test filters were fitted to the extract ducts of a standard central air conditioning system, and were left in place for 1, 2, or 4 weeks. In a separate experiment to analyze contributing factors, the test filters were changed following every operation. Green dots showing a reaction with leucomalachite green method were counted. In the accumulation experiment, the number of positive dots tended to increase over time (26, 60, and 143 dots after 1, 2, and 4 weeks, respectively). The distance between the test filters and surgical field ranged from 3.8 to 4.6 m. In our analysis of contributing factors, positive filters were present in 9 of 10 surgeries that used high-speed instruments and in 16 of 17 using electric coagulator devices. Surgical procedures performed with these devices produce aerosolized blood, which can float in the operating room. Thus, caution must be taken by perioperative staff, such as anaesthetists and surgical assistants, as well as by surgeons.

Far from being obsolete, serology is still a significant part of the forensic biologist's toolkit. Testing for body fluids can save a great deal of time and effort later in the analytical stream of things (that is, DNA analysis). There can be no argument that serology has taken a backseat to DNA, but the argument should be made for retaining a battery of serology tests in the modern forensic laboratory. New methods being researched, such as proteomics, offer serology a renewed life and application as biologists discover more and different ways to identify the substances that make up our bodies.

This paper presents the results of a proficiency test (APLAC T058) for malachite green (MG) and leucomalachite green (LMG) in swamp eel (Monopterus albus). The programme was organized by the Hong Kong Government Laboratory and Hong Kong Accreditation Service (HKAS), under the auspices of the Asia-Pacific Laboratory Accreditation Co-operation (APLAC) in 2007. Results submitted by participants were compared with the assigned reference values, which were determined by an accurate liquid chromatography-isotope dilution mass spectrometry (LC-IDMS) technique, and their performance was evaluated on the basis of z-score index. The distribution of data was very wide and discrepancy from the assigned reference values was found to be method dependent. Only 48% and 62% of participants achieved satisfactory z-scores (i.e. |z|or=2) for MG and LMG, respectively. With the provision of reference values, the programme served to establish an external quality control mechanism for assessing the measurement capabilities of participating laboratories in the determination of MG and LMG in eel samples.

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link. Four presumptive blood tests, Hexagon OBTI, Hemastix , Leucomalachite green (LMG), and Kastle-Meyer (KM) were compared for their sensitivity in the identification of dried bloodstains. Stains of varying blood dilutions were subjected to each presumptive test and the results compared. The Hexagon OBTI buffer volume was also reduced to ascertain whether this increased the sensitivity of the kit. The study found that Hemastix was the most sensitive test for trace blood detection. Only with the reduced buffer volume was the Hexagon OBTI kit as sensitive as the LMG and KM tests. However, the Hexagon OBTI kit has the advantage of being a primate specific blood detection kit. This study also investigated whether the OBTI buffer within the kit could be utilized for DNA profiling after presumptive testing. The results show that DNA profiles can be obtained from the Hexagon OBTI kit buffer directly.

Two major trends are observed in the analysis of veterinary drugs and growth-promoting agents. First is the selection of sample material for monitoring the use of registered veterinary drugs. Traditionally meat, kidney and liver were analyzed but, due to the food scandals in which meat was very often involved, the consumption of alternative products (e.g., eggs and fish) has become more popular and therefore more of interest for residue-monitoring programmes. Most food scandals started with contamination of animal feed, so feed has also gained interest for monitoring purposes. For the detection of unauthorized substances (e.g., growth-promoting agents), the matrix hair is frequently used because residues can be detected in hair even a long time after treatment. Second, the techniques used for residue analysis are moving from target-orientated methods, mainly based on liquid chromatography in combination with triple-quadrupole mass-spectrometric detection (LC-QqQ-MS), towards accurate mass full-scan MS techniques (e.g., time-of-flight (ToF)-MS and Fourier-transform(FT)-MS. Full-scan MS techniques enable retrospective analysis (i.e. without re-injecting the sample) and real multi-residue analysis (including different classes of veterinary drugs). The application of full-scan MS also has consequences for separation and extraction techniques, which have to be applicable to a broad range of compounds differing in physical and chemical properties. Experience shows that ToF-MS in combination with ultra-performance LC (UPLC) is very powerful for multi-residue analysis. The introduction of new MS techniques also has consequences for European Union (EU) criteria defined for confirmation of the identity of compounds. It is suggested that both mass-resolution and mass-accuracy data influence identity confirmation and both parameters should be implemented in the revision of European Commission Decision 2002/657/EC. (C) 2007 Elsevier Ltd. All rights reserved.

A method has been developed to analyse for malachite green (MG), leucornalachite green (LMG), crystal violet (CV) and leucocrystal violet (LCV) residues in salmon. Salmon samples were extracted with acetonitrile:Mclllvain pH 3 buffer (90: 10 v/v), sample extracts were purified on a Bakerbond strong cation exchange solid phase extraction cartridge. Aliquots of the extracts were analysed by LC-MS/MS. The method was validated in salmon, according to the criteria defined in Commission Decision 2002/657/EC. The decision limit (CC alpha) was 0.17, 0.15, 0.35 and 0.17 mu g kg(-1), respectively, for MG, LMG, CV and LCV and for the detection capability (CCO) values of 0.30, 0.35, 0.80 and 0.32 mu g ka(-1), respectively, were obtained. Fortifying salmon samples (n = 6) in three separate assays, show the accuracy to be between 77 and 113% for MG, LMG, LCV and CV. The precision of the method, expressed as RSD values for the within-laboratory reproducibility, for MG, LMG and LCV at the three levels of fortification (1, 1.5 and 2.0 mu g kg(-1)), was less than 13%. For CV a more variable precision was obtained, with RSD values ranging between 20 and 25%. (c) 2006 Elsevier B.V. All rights reserved.

Presumptive blood detection tests are used by forensic investigators to detect trace amounts of blood or to investigate suspicious stains. Through the years, a number of articles have been published on the popular techniques of the day. However, there is no single paper that critiques and compares the five most common presumptive blood detection tests currently in use: luminol, phenolphthalein (Kastle-Meyer), leucomalachite green, Hemastix and the forensic light source. The present authors aimed to compare the above techniques with regard to their sensitivity, ease of use and safety. The luminol test was determined to be the most sensitive of the techniques, while Hemastix is a suitable alternative when the luminol test is not appropriate.

Malachite green (MG) is still illegally used as a fungicide in aquaculture. In fish it is absorbed and metabolised to its major reduced metabolite, leucomalachite green (LMG). This latter represents the main residue found in fish tissues and may persist for several months. Since MG, suspected to act as a tumour promoter in vitro and in vivo, might be also present as a residue in fish, the present study was undertaken to ascertain the in vitro toxicity of both compounds in two human tumour cell lines (Caco-2 and HEp-2). After 24h incubation with MG, significant decreases of cell viability, measured by neutral red uptake (NRU) or total protein content (TPC) as well as proliferation capability (colony-forming ability, CFA) were noticed in HEp-2 cells; the mean IC(50) value was about 2 microM. As regards the differentiated Caco-2 cells, MG caused a dose-related significant cytotoxicity, measured either by MTT test, the LDH leakage or NRU, with a mean IC(50) value of about 15 microM. By contrast, LMG disclosed, in both cell lines, a lower cytotoxicity compared to MG. These results also show that HEp-2 cells are more sensitive than intestinal cells to the toxic action of both compounds.

We generally use luminal (LM) and leucomalachite green (LMG) in presumptive tests at crime scenes. LM is used to search for scattered blood traces or blood stains. LMG is used to detect fingerprints in latent blood stains and blood stains in laboratory settings. When only trace specimens are available, DNA extraction must be performed from LM- or LMG-treated specimens. No reports to date have been published on the actual effects of LMG on DNA extraction, although some reports suggest the potential influence of LM on DNA extraction. This study examined the effects of LM and LMG on DNA typing.

Purpose: To quantify the sensitivity and stability of the Presage dosimeter in sheet form for different concentrations of chemicals and for a diverse range of clinical photon energies. Methods: Presage polymer dosimeters are formulated to investigate and optimize their sensitivity and stability. The dosimeter is composed of clear polyurethane base, leucomalachite green reporting dye, and bromoform radical initiator in 1mm thick sheets. The chemicals are well mixed together, cast in an aluminum mold, and left to cure at 60 psi for a minimum of 2 days. Dosimeter response will be characterized at multiple energies including Co-60, 6 MV, 15 MV, 50 kVp, and 250 kVp. The dosimeters are read by an Epson 10000 XL scanner at 800 dpi, 2^16 bit depth. Red component images are analyzed with ImageJ. Results: Analysis of optical density verse dose for Co-60 energies indicates that the bromoform containing Presage was able to quantify dose from 0 to 300 Gy, with saturation beyond 300 Gy. Initial results show two regions of linear response, 0–100 Gy and 150–300 Gy. The 150–300 Gy region has a sensitivity of 0.0024 net OD/Gy. Further results on other energies are still in progress. Conclusions: This work shows the potential for use of thin sheets of Presage dosimeter as a dosimeter capable of being analyzed with a flatbed scanner.

A comparison between a commercial leucomalachite green (LMG) dye and three newly synthesised derivatives incorporated into the PRESAGE® dosimeter was carried out to determine their effect on the sensitivity and post-response photo fading of the dosimeter. For all of the substituted LMG derivatives (with either methoxy, chlorine or bromine substituents), the sensitivity of the resulting dosimeters to radiation dose increased significantly and was dependent on the type of LMG derivative used, with the bromine substituted derivative showing the highest sensitivity increase (450%) followed by chlorine and methoxy substituted derivatives (340%, 200 %, respectively) relative to commercial LMG. All LMG dyes investigated showed similar post-response photo fading characteristics except the methoxy-LMG derivative, which showed a slight improvement in post-response photo-retention. Refereed/Peer-reviewed

During a review of its activities, the organic analysis working group of the consultative committee for amount of substance noted that evidence supporting institute capabilities for providing services supporting the food sector was lacking. A request was made for a proposal of a study that would imply an institute's broader capability for the analysis of trace residues in food. Malachite green is a triphenylmethane dye with powerful antifungal properties. Its presence in food is not permitted and routine monitoring is performed in many regions at the ?g/kg level. Its measurement is considered challenging for a number of reasons. Malachite green readily metabolises to leucomalachite green, with the sum of both forms being reported as 'total' malachite green. However, the two compounds have different stability and extraction requirements and often readily interconvert, proving a challenge for the successful quantification of both. The study material was a specially prepared homogenized salmon tissue from fish that had been administered with malachite green. Laboratories were requested to measure malachite green and leucomalachite green with the sum of both being reported and used for this key comparison. All laboratories used liquid chromatography?mass spectrometry with a compound-specific isotope dilution method. Six laboratories participated in the study, with all six providing results for malachite green, leucomalachite green and 'total' malachite green, reported as the sum of the two forms. A number of estimators were proposed for the calculation of the key comparison reference value (KCRV), with the working group deciding on the median and its uncertainty estimate as the most appropriate. This resulted in a KCRV of (9.77 ? 0.35) ng/g. The calculated degrees of equivalence for all laboratories were less than 1?ng/g. This was considered exceptional, especially when the complexity of the matrix, the differential partitioning of the two interconverting compounds and their sub 10?ng/g levels in the fish are considered. Participating labs demonstrated their capability in extracting trace levels of potentially unstable compounds from a solid matrix. Successful participation is considered indicative of an institute's ability to measure low levels (1 ng/g to 100 ng/g) of medium to high polarity residues in muscle tissue. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Triphenylmethane dyes, such as malachite green (MG), crystal violet (CV) and brilliant green (BG), have been widely used to prevent and treat infections in aquaculture products due to high efficacy, availability and low price. These compounds undergo metabolism towards reduced leucoforms, such as leucomalachite green (LMG), which can also be found in fish. The present review discusses the most relevant extraction methods as well as the main separation and detection techniques used for the determination of triphenylmethane dyes in seafood. Specifically, it is mainly focused on the application of liquid chromatography (LC) coupled with mass spectrometry (MS), including low and high resolution analysers, which are currently applied to identify and quantify dyes in seafood.

The purpose of this work was to conduct a comparative study of the sensitivity and specificity of phenolphthalein, tetramethylbenzidine, leucomalachite green, and orthotolidine as presumptive tests for blood. The findings of this study indicate that the phenolphthalein and the leucomalachite green tests are the most specific and that the tetramethylbenzidine and orthotolidine tests are the most sensitive of the group. The author concludes that the phenolphthalein test is the best single test for evaluating suspected bloodstains.

Purpose: To develop a formulation of PRESAGE™, a three‐dimensional radiochromic dosimeter, that does not under‐respond in the high LET region of a protonbeam. Previous investigations with PRESAGE™ report a 38% under‐response when irradiated in the SOBP of a protonbeam compared to 6 MV photons.Method and Materials: A new PRESAGE™ formulation was developed for this study by replacing the reporter molecule in the original formulation, leucomalachite green (LMG), with a new LMG derivative. Dosimeters were manufactured using LMG and the LMG derivative and irradiated in the SOBP region of a 250 MeV protonbeam to doses from 1 Gy to 5 Gy to develop a dose response curve for each formulation. An additional dose response curve was developed for the LMG derivative by irradiating dosimeters to doses from 1 Gy to 5 Gy using 6 MV photons.Results: The response of the LMG derivative was 52% more than that of the original formulation when irradiated using a protonbeam. The response of the LMG derivative to protons and photons was within 3% over the entire dose range. The LMG derivative was also found to be more stable post‐irradiation than the original formulation. Conclusion: The under‐response of PRESAGE™ to protons has been corrected by replacing the LMG reporter molecule with a new LMG derivative. The molecular structure of the new derivative was based on the presumption that the under‐response in the original formulation was due to shifting of the equilibrium of the colored malachite green form back to the non‐colored leuco form when irradiated in high LET beams. The data for the new LMG derivative supports this mechanism. Additional studies will be presented that further characterize the response of the new PRESAGE™ formulation. The investigation was supported by PHS grant CA 10953 awarded by the NCI, DHHS.

Purpose: Presage is a new radiochromic material with substantial promise as a practical and convenient 3D dosimeter. Here we investigate new formulations of PRESAGETM to determine formulations that have high sensitivity, high stability, and/or are amenable to repeat measurements.Method and Materials: PRESAGETM formulations were manufactured in 2 mL glass vial samples and were irradiated in a 6MV photon beam to a dose of 5 Gy. Fifteen formulations were studied, eight of which were variations containing leucomalachite green (LMG) and seven variations containing leuco crystal violet (LCV). The transmission spectra (500–700 nm) were measured in a spectrophotometer for each sample pre‐irradiation and then approximately one hour post‐irradiation. Subsequent spectrum acquisitions were recorded at 2, 24, 48, and 72 hours post‐irradiation to ascertain the stability of optical density changes. Results: Overall, the LCV formulations show greater sensitivity than the formulations containing LMG. The most promising LCV formulations exhibit a 15 – 33 % increase in post‐irradiation absorption relative to pre‐irradiation. The LCV formulations had minimal post‐irradiation color bleaching from 2 to 72 hours, while the LMG formulations varied widely in stability post‐irradiation. A number of the LMG samples returned to their pre‐irradiation optical density, suggesting the possibility of a formulation which could be reusable. In addition, two of the formulations which contained polymeric acrylates along with the leuco dyes increased transmission relative to pre‐irradiation, illustrating the intriguing potential of an ‘inverse radiochromic dosimeter’ (i.e. a dosimeter that becomes clearer after irradiation). Conclusions: Absorption changes post‐irradiation identified LCV formulations with the initial response and stability for application in 3D dosimetry. In addition, LMG formulations were identified that may permit the unique potential for ‘inverse radiochromic dosimetry’ and reusability.

The electrothermographic behaviour of poly (acrylonitrile butadiene styrene) (ABS) pure as well as sensitized with different weight percentages of leucomalachite green, (LMG) has been studied. The following important parameters were investigated: (i) maximum acceptance potential; (ii) surface potential decay at room temperature and under exposure to infrared (IR); (iii) contrast potential (i.e. difference in surface potential of areas maintained at room temperature and of areas exposed to infrared); (iv) thermosensitivity (i.e. rate of decay of electrical potential when plate is exposed to infrared); and (v) retentivity as determined by rate of decay of electrical potential at room temperature. A solution cast layer of ABS on aluminum substrate shows very high charge acceptance on corona charging. Addition of a thermosensitizer (LMG) in the polymer matrix shows enhanced contrast potential at constant IR exposure. The thermosensitivity of ABS increases considerably with the addition of leucomalachite green. Optimum conditions for the suitability of the polymer in electrothermography is determined by studies on different weight proportions of sensitizer. Corresponding carrier mobilities are calculated from surface potential decay characteristics at room temperature.

The electrothermographic behaviour of poly(styrene-co-allyl alcohol) sensitized with different amounts of leucomalachite green has been studied. The following parameters were investigated: maximum acceptance potential, surface potential decay at room temperature and under infrared irradiation, contrast potential, residual potential, and thermosensitivity. Pure as well as sensitized layers show quite high charge acceptance on corona charging. Addition of the thermosensitizer causes an enhanced contrast potential at constant IR exposure. Das elektrothermographische Verhalten von Poly(styren-co-allylalkohol) bei Sensibilisierung mit unterschiedlichen Mengen Leucomalachitgrun wurde untersucht. Die folgenden Parameter wurden ermittelt: Maximale Spannungsaufnahme, Abnahme des Oberflachenpotentials bei Raumtemperatur und bei Infrarotbestrahlung, Kontrastpotential, Restpotential und Thermoempfindlichkeit. Sowohl reine als auch sensibilisierte Filme zeigen eine betrachtliche Ladungsaufnahme bei einer Coronabehandlung. Die Zugabe des Thermosensibilisators fuhrt zu einer Zunahme des Kontrastpotentials bei konstanter Infrarotbelichtung.

Important electrothermographic characteristics such as charge acceptance, surface-potential decay with and without exposure to infrared radiations, retention of surface charge, contrast potential and residual potential of pure and sensitized cellulose acetate layers have been investigated. An attempt has been made to explain the results on the basis of electrical properties. Leucomalachite Green (LMG) is found to be very effective in controlling the thermosensitivity in the cellulose acetate layers. Cellulose acetate layer sensitized with 20% by wt of LMG shows a suitable high-contrast potential of 890 V with zero residual potential on heating its surface to 62° C and is a suitable material for electrothermographic and related applications.

A new colorimetric assay for the determination of serum free hemoglobin utilizing the noncarcinogenic compound leucomalachite green is described. The reaction is complete in 8 min, with the resulting color stable for at least 30 min. The absorption maximum for the leucomalachite green reaction product was observed at 617 nm. Precision studies at 50 and 300 mg/l free hemoglobin concentrations resulted in within-run variations of 1.9 and 1.7%, while the day-to-day variations were 6.9 and 4.0%, respectively. Accuracy studies at concentrations of 50, 150 and 300 mg/l resulted in recoveries of 88, 95 and 98% of theoretical values.