DOCSLIB.ORG

Development of a Field Method for Measuring Manganese in Welding

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Development of a Field Method for Measuring Manganese in Welding Development of a field method for measuring manganese in welding fume A. Dale Marcyab and Pamela L. Drake*a Received 11th April 2007, Accepted 14th August 2007 First published as an Advance Article on the web 30th August 2007 DOI: 10.1039/b705252a Workers who perform routine welding tasks are potentially exposed to fume that may contain manganese. Manganese may cause respiratory problems and is implicated in causing the occurrence of Parkinson-like symptoms. In this study, a field colorimetric method for extracting and measuring manganese in welding fume was developed. The method uses ultrasonic extraction with an acidic hydrogen peroxide solution to extract welding fume collected on polyvinyl chloride filters. Commercially available pre-packaged reagents are used to produce a colored solution, created by a reaction of manganese(II) with 1-(2-pyridylazo)-2-naphthol. Absorbance measurements are then made using a portable spectrophotometer. The method detection limit and limit of quantification (LOQ) were 5.2 mg filterÀ1 and 17 mg filterÀ1, respectively, with a dynamic range up to 400 mg filterÀ1. When the results are above the LOQ for the colorimetric method, the manganese masses are equivalent to those measured by the International Organization for Standardization Method 15202-2, which employs a strong acid digestion and analysis using inductively coupled plasma-optical emission spectrometry. Introduction that chronic exposure to elevated manganese levels in the workplace results in increased respiratory problems.11–13 Welders may be exposed to a wide variety of hazardous In the United Stated, there are currently three workplace 1,2 substances while performing routine welding tasks. The exposure limits for manganese. The National Institute for fume that is generated during welding is a complex mixture Occupational Safety and Health (NIOSH) recommended of metal oxides that condense from the gas phase to form very exposure limit (REL) for manganese is 1 mg mÀ3 as an 8 h 3 small particles. The composition of the fume depends upon time-weighted average (TWA), and 3 mg mÀ3 as a short-term the type of welding process used and the chemical composition exposure limit.14 The Occupational Safety and Health Admin- of the metals being joined. A wide variety of methods are used istration (OSHA) permissible exposure limit (PEL) is to join metals together. Some of the more common types are 5mgmÀ3 (ceiling limit).14 The American Conference of shielded manual metal arc welding (SMAW), gas metal arc Governmental Industrial Hygienists (ACGIH) has established welding (GMAW), and flux-cored arc welding (FCAW). In a threshold limit value (TLV) of 0.2 mg mÀ3 for manganese.15 FCAW and SMAW, fluxes are incorporated into the consum- In the current analytical methods for determining the 1,2 able electrodes to shield against atmospheric gases. Manga- quantity of manganese in welding fume, a sample of the nese may be present in both the flux material and the metal particles in workplace air is collected on polyvinyl chloride electrodes. (PVC) filters or mixed cellulose ester (MCE) filters mounted in Welding fume may contain irritants and can be toxic to the plastic cassettes. Samples are collected using a personal sam- respiratory system, possibly causing pulmonary edema, pling pump at a flow rate of 2 L minÀ1, over a period of 8 h. chronic bronchitis, emphysema, pneumonia, asthma, welder’s The sample is sent to an accredited laboratory for an analysis 4 lung, and metal fume fever. Manganese is one of the compo- of the total manganese content using strong acid digestion and nents of welding fume that may have serious effects on measurement by inductively coupled plasma-optical emission 1,5 health. Some studies have shown that welders exposed to spectrometry (ICP-OES).16,17 The process typically requires fumes that contains manganese may have an increased risk of 4–6 weeks from the time the samples are collected until the 6–8 developing Parkinson-like symptoms, while other studies results of the analysis are reported. With this turnaround time, 9,10 have found no linkage. These symptoms include a fixed it is difficult to relate work practices to exposure levels in a gaze, bradykinesia, postural difficulties, rigidity, tremor, dys- timely fashion. The ability to measure manganese in welding tonia, and decreased mental status. Other studies have shown fume within 24 h would allow managers, supervisors, and/or safety personnel to communicate exposure levels to workers and take corrective actions to reduce exposure. a The goal of this study was to develop a rapid field method US Department of Health and Human Services, Centers for Disease s Control and Prevention, National Institute for Occupational Safety for measuring manganese in welding fume. HACH method and Health, Spokane Research Laboratory, 315 E. Montgomery 814918 is a colorimetric method for determining manganese in Ave, Spokane, WA 99207, USA. E-mail: [email protected]; Fax: water and wastewater. By adapting this method, the manga- +1-509-354-8099 b North Idaho College, 1000 W. Garden Ave, Coeur d’Alene, ID nese is extracted from the filters and converted to the soluble 83814, USA. manganese(II) form. An ultrasonic bath is used to extract the fume into an acidic solution of hydrogen peroxide. After solution (SPEX CertiPrep standard solution in 2% nitric acid, dissolution, 1-(2-pyridylazo)-2-naphthol (PAN) indicator is Metuchen, New Jersey, USA) were used to prepare spiking, added to the solution; it combines with manganese to form standard, and calibration check solutions. Iron solutions at an orange-colored complex. The absorbance is then measured 1000 mg LÀ1 were prepared by dissolving analytical grade on a spectrophotometer. In order to ensure that the new ferrous ammonium sulfate (EM Science, Cherry Hill, New extraction procedure was accurate, precise, and compatible Jersey, USA) and ferric nitrate nonahydrate (JT Baker, with the HACHs method, a series of experiments were Mallinckrodt Baker, Inc., Phillipsburg, New Jersey, USA) in conducted to evaluate analytical recovery, stability, method deionized water (18 MO, Millipore Milli-Q Plus, Molsheim, detection limit, and interferences. France). Analytical grade manganese(IV) oxide was obtained from JT Baker (Mallinckrodt Baker, Inc., Phillipsburg, New Jersey, USA). Nitric, hydrochloric, and sulfuric acids were Experimental obtained from OPTIMA (Seastar Chemicals Inc., Pittsburgh, Air sample generation and collection Pennsylvania, USA). The 50% hydrogen peroxide solution, ascorbic acid powder pillows, alkaline cyanide reagent, and Welding fume samples were collected on PVC filters (37 mm, PAN indicator solution were obtained from HACHs 5.0 mm pore size, with cellulose backup pad, SKC, Inc., Eighty (Loveland, Colorado, USA). Four, Pennsylvania, USA) using a custom-made multiport sampler. The multiport sampler was connected to a high- volume (15 L minÀ1) air sampling pump (Gilian AirCon2, West Caldwell, New Jersey, USA) and it collected eight Experimental methods samples simultaneously with a measured flow rate of 1.7 (Æ0.1) L minÀ1 for each individual port. All welding was Acidic hydrogen peroxide extraction and colorimetric analysis performed on soft steel using SMAW. Three types of electro- The field method for measuring manganese in welding fume des were used: UTP 711B ( 1% Mn; Bohler Thyssen Weld- o was evaluated by measuring the recovery of manganese that ing, Stafford, Texas, USA); E11018-M ( 5% Mn; Hobart o was added to PVC filters in one of three ways. In the first Welding Products, Appleton, Wisconsin, USA); and ArcTec procedure, the PVC filters were placed into 15 mL centrifuge 41 (16% Mn; ArcTec Alloys Ltd, Calgary, Alberta, Canada). tubes and solid manganese(IV) oxide was weighed directly onto Materials and equipment the filters. In the second method, known concentrations of manganese(II) in solution were pipetted onto the PVC filters in For some experiments, the PVC filters were placed into 15 mL the 15 mL centrifuge tubes. In the third technique, welding centrifuge tubes (Falcon, Becton-Dickinson, Franklin Lakes, fumes were collected on PVC filters in cassettes using a New Jersey, USA). The addition of reagents and deionized multiport sampler with a high-volume pump. water was performed with a mechanical pipette (Rainin In- The filters were then analyzed using the colorimetric method strument Company, Inc., Franklin Lakes, New Jersey, USA). as follows. The cassettes were opened and the filters were A vortex mixer (Barnstead International, Dubuque, Iowa, transferred to 15 mL centrifuge tubes. Two millilitres of USA) was used to mix the samples prior to extraction in the deionized water were added, followed by 0.5 mL of 6 M ultrasonic bath (117-V, 50 Hz, Crest Ultrasonics, Trenton, sulfuric acid and 3.0 mL of 3% hydrogen peroxide. The tubes New Jersey, USA). An aliquot of the extraction solution was were capped and the contents were mixed using a vortex mixer, s transferred to a HACH 25 mL sample cell (2.0 cm path ensuring that the filters were completely submerged in the length) with cap (Loveland, Colorado, USA) and diluted to extraction solution. The centrifuge tubes were placed in an s 10 mL. After the HACH reagents were added, the absor- ultrasonic bath and the filters were extracted for 30 min. In bance was measured using a DR/2400 spectrophotometer order to allow for complete dissolution of the manganese, the s (HACH Company, Loveland, Colorado, USA). samples were allowed to set in the acidic hydrogen peroxide For other experiments, the PVC filters were placed into extraction solution for a minimum of 2 h before analysis. After 25 mL beakers (Fisher Scientific, Hampton, New Hampshire, extraction, 4.5 mL of deionized water was added to the USA) and sequentially digested with concentrated nitric and centrifuge tubes and the contents were mixed using the vortex hydrochloric acids on a hot-plate (VWR International, Inc., mixer. An aliquot of the extraction solution in each of the West Chester, Pennsylvania, USA).
Load more

Recommended publications
  • "Method 366.0
    Method 366.0 Determination of Dissolved Silicate in Estuarine and Coastal Waters by Gas Segmented Continuous Flow Colorimetric Analysis Jia-Zhong Zhang, Cooperative Institute for Marine and Atmospheric Studies, Rosenstiel School of Marine and Atmospheric Science, Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration, University of Miami, Miami, FL 33149 George A. Berberian, National Oceanic and Atmospheric Administration, Atlantic Oceanographic and Meteorological Laboratory, Ocean Chemistry Division, Miami, FL 33149 Project Officer Elizabeth J. Arar Version 1.0 September 1997 National Exposure Research Laboratory Office of Research and Development U.S. Environmental Protection Agency Cincinnati, Ohio 45268 366.0-1 Method 366.0 Determination of Dissolved Silicate in Estuarine and Coastal Waters by Gas Segmented Continuous Flow Colorimetric Analysis 1.0 Scope and Application contained in the sample with molybdate in acidic solution. The $-molybdosilicic acid is then reduced by ascorbic 1.1 This method provides a procedure for the acid to form molybdenum blue. The absorbance of the determination of dissolved silicate concentration in molybdenum blue, measured at 660 nm, is linearly estuarine and coastal waters. The dissolved silicate is proportional to the concentration of silicate in the sample. mainly in the form of silicic acid, H4SiO4, in estuarine and A small positive error caused by differences in the coastal waters. All soluble silicate, including colloidal refractive index of seawater and reagent water, and silicic acid, can be determined by this method. Long chain negative error caused by the effect of salt on the color polymers containing three or more silicic acid units do not formation, are corrected prior to data reporting.
    [Show full text]
  • 1 Development of a Disposable Pyruvate
    Biosensors and Bioelectronics, Volume 21, Issue 11, 15 May 2006, pp2176-2179. Development of a disposable pyruvate biosensor to determine pungency in onions (Allium cepa L.) L.A. Abayomi, L.A. Terry*, S.F. White and P.J. Warner Plant Science Laboratory, Cranfield University, Bedfordshire, MK45 4DT, UK * Corresponding author. Email address: [email protected] (L. A. Terry). Abstract A disposable prototype pyruvate biosensor was constructed using pyruvate oxidase immobilised on mediated meldolas blue electrodes to determine pungency in onions (Allium cepa L.). The operating potential was +150 mV. A strong correlation between the biosensor response and untreated onion juice of known pyruvate concentration 2 – 12 mol/g fresh weight (FW) was demonstrated. The biosensor was able to differentiate between low and high pungency onions. The detection limit using 1 unit of pyruvate oxidase was 1 – 2 mol/g FW. Optimum concentrations of co-factors TPP and FAD and MgSO4 comprising the enzyme cocktail were determined as being 0.04 mM, 0.1 mM and 30 mM, respectively. Keywords: meldolas blue; fresh produce; quality assurance; sweet onions 1. Introduction Bulb onions are the second most important horticultural crop after tomatoes (Griffiths et al. 2002) and are consumed worldwide for their unique flavour. Increasingly, low pungency bulbs (often referred to colloquially as mild and/or sweet onions) are consumed raw in the USA and elsewhere. Pyruvate concentration (mol/g FW) in macerated onion 1 tissue is used as a quality assurance indicator of pungency (Schwimmer and Weston, 1961; Wall and Corgan, 1992; Crowther et al., 2005) or flavour intensity in most onion producing countries.
    [Show full text]
  • A Guide to Colorimetry
    A Guide to Colorimetry Sherwood Scientific Ltd 1 The Paddocks Cherry Hinton Road Cambridge CB1 8DH England www.sherwood-scientific.com Tel: +44 (0)1223 243444 Fax: +44 (0)1223 243300 Registered in England and Wales Registration Number 2329039 Reg. Office as above Group I II III IV V VI VII VIII Period 1A 8A 1 2 1 H 2A 3A 4A 5A 6A 7A He 1.008 4.003 3 4 5 6 7 8 9 10 2 Li Be B C N O F Ne 6.939 9.0122 10.811 12.011 14.007 15.999 18.998 20.183 11 12 13 14 15 16 17 18 3 Na Mg 3B 4B 5B 6B 7B [---------------8B-------------] 1B 2B Al Si P S Cl Ar 22.99 24.312 26.982 28.086 30.974 32.064 35.453 39.948 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 39.102 40.08 44.956 47.9 50.942 51.996 54.938 55.847 58.933 58.71 63.546 65.37 69.72 72.59 74.922 78.96 79.904 83.8 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 85.47 87.52 88.905 91.22 92.906 95.94 [97] 101.07 102.91 106.4 107.87 112.4 114.82 118.69 121.75 127.6 126.9 131.3 55 56 57* 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 6 Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Ti Pb Bi Po At Rn 132.91 137.34 138.91 178.49 180.95 183.85 186.2 190.2 192.2 195.09 196.97 200.59 204.37 207.19 208.98 209 210 222 87 88 89** 104 105 106 107 108 109 110 111 112 114 116 7 Fr Ra Ac Rt Db Sg Bh Hs Mt 215 226.03 227.03 [261] [262] [266] [264] [269] [268] [271] [272] [277] [289] [289] 58 59 60 61 62 63 64 65 66 67 68 69 70 71 * Lanthanides Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 140.12 140.91 144.24 145 150.35 151.96 157.25 158.92 152.5 164.93 167.26 168.93 173.04 174.97 90 91 92 93 94 95 96 97 98 99 100 101 102 103 ** Actinides Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr 232.04 231 238 237.05 239.05 241.06 244.06 249.08 251 252.08 257.1 258.1 259.1 262.11 The ability to analyse and quantify colour in aqueous solutions and liquids using a colorimeter is something today’s analyst takes for granted.
    [Show full text]
  • Kinetics of the Uncatalyzed, Alkaline Decomposition of Hydrogen Peroxide Trice Walter Haas Iowa State University
    Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1960 Kinetics of the uncatalyzed, alkaline decomposition of hydrogen peroxide Trice Walter Haas Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Physical Chemistry Commons Recommended Citation Haas, Trice Walter, "Kinetics of the uncatalyzed, alkaline decomposition of hydrogen peroxide " (1960). Retrospective Theses and Dissertations. 2645. https://lib.dr.iastate.edu/rtd/2645 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. KINETICS OF THE UN CATALYZED, ALKALINE DECOMPOSITION OF HYDROC-EN PEROXIDE by Trice Walter Haas A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of The Requirements for the Degree of DOCTOR OF PHILOSOPHY Major Subject: Physical Chemistry Approved: Signature was redacted for privacy. In Charge of Major Work Signature was redacted for privacy. Head of Major Department Signature was redacted for privacy. Iowa State University Of Science and Technology Ames, Iowa I960 il TABLE OP CONTENTS Page I. INTRODUCTION 1 II. EXPERIMENTAL 8 A. Apparatus 8 B. Quenching Technique 9 C. Analytical Techniques 10 D. Purification Methods 13 III. RESULTS AND DISCUSSION 20 A. The Homogeneous, Uncatalyzed Decomposition 20 1» General 20 2. Impurity effects 20 3* Surface effects 22 L Effect of light 27 5. Inert ions 28 6. Experimental results and discussion 29 7* Sources of error $1 B.
    [Show full text]
  • Cell Biology
    Cell Biology - Assays Kits Apoptosis For your research Interchim offers a comprehensive line of products : Technical tip ! Membrane assays (AnnexinV, AppolerCentage) ! Caspase assays Apoptosis is a programmed, cell-autonomous death process, known to impact every stage of ! Mitochondria assays life of multicellular eukaryotes. It is involved in a variety of physiological and pathological events, ranging from normal development (embryo Method Advantages Disadvantages growth, postnatal organ modeling and cell Apoptosis membrane alteration : Dye Single apoptotic cell (IHC). Quick and Limited information available on cell turnover) to diseases and disorders (cancer, (uptake bioassay: APOPercentage). easy to use. Assay can also be membrane composition. organ failure and ageing, and quantified, using a digital camera or a neurodegenerative diseases). During microplate colorimeter/fluorimeter. apoptosis, the caspases execute the Necrotic cells cannot retain the dye. disassembly of cellular components by Several hundred assays can be proteolytic cleavage of a variety of substrates, such as poly-(ADP ribose) polymerase (PARP), performed in one day. DNA-dependent protein kinase (DNA-PK), Apoptosis membrane alteration: Sensitivity Single cell (FCM, IHF). Does not discriminate between apoptotic topoisomerases, and protein kinase C (PKC). (Annexin V binding) Confirms the occurrence of and necrotic cells. At least ten caspases have been discovered. phosphatidylserine flippase in Some of these caspases identify and cleave a apoptotic cells, and the activity of specific peptide substrate, while others initiator caspases. recognize the same peptide substrate. Fluorescence Activated Cell Sorter Good option for suspension cells. The equipment is designed for cell (FACS). counting and cell sorting. Excessive physical force, to remove cell clumps, can damage cells. Lower Sensitivity (>100 Selection guide apoptotic cells to discern cluster in a sample scan.
    [Show full text]
  • Reclamation of Hexavalent Chromium Using Catalytic Activity of Highly Recyclable Biogenic Pd(0) Nanoparticles R
    OPEN Reclamation of hexavalent chromium using catalytic activity of highly recyclable biogenic Pd(0) nanoparticles R. M. Tripathi1,2 & Sang J. Chung1* Hexavalent chromium is extremely toxic and increasingly prevalent owing to industrialisation, thereby posing serious human health and environmental risks. Therefore, new approaches for detoxifying high concentrations of Cr (VI) using an ultralow amount of catalyst with high recyclability are increasingly being considered. The catalytic conversion of Cr (VI) into Cr (III) was previously reported; however, it required a large amount of catalyst to reduce a low concentration of Cr (VI); further, pH adjustment and catalyst separation had to be performed, causing issues with large-scale remediation. In this study, an unprecedented eco-friendly and cost-efective method was developed for the synthesis of Pd nanoparticles (PdNPs) with a signifcantly narrow size distribution of 3–25 nm. PdNPs demonstrated the presence of elemental Pd with the zero oxidation state when analysed by energy-dispersive X-ray analysis and X-ray photoelectron spectroscopy. The PdNPs could detoxify a high concentration of Cr (VI), without the need to adjust the pH or purify the nanoparticles for reusability. The reusability of the PdNPs for the catalytic conversion of Cr (VI) into Cr (III) was >90% for subsequent cycles without the further addition of formic acid. Thus, the study provides new insights into the catalytic reclamation of Cr (VI) for industrial wastewater treatment. Heavy-metal pollution is a serious hazard and a global issue due to the increase in industrial and agricultural activities. Several toxic pollutants, such as inorganic ions, metals, and synthetic organic matter, are released into water.
    [Show full text]
  • Estimation of Chemical Oxygen Demand in Wastewater Using UV
    Estimation of Chemical Oxygen Demand in WasteWater using UV-VIS Spectroscopy by Tasnim Alam B.Sc.(Hons.), Military Institute of Science and Technology (MIST), Bangladesh, 2010 Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Applied Science in the School of Mechatronic Systems Engineering Faculty of Applied Sciences c Tasnim Alam 2015 SIMON FRASER UNIVERSITY Summer 2015 All rights reserved. However, in accordance with the Copyright Act of Canada, this work may be reproduced without authorization under the conditions for “Fair Dealing.” Therefore, limited reproduction of this work for the purposes of private study, research, criticism, review and news reporting is likely to be in accordance with the law, particularly if cited appropriately. APPROVAL Name: Tasnim Alam Degree: Master of Applied Science Title of Thesis: Estimation of Chemical Oxygen Demand in WasteWater us- ing UV-VIS Spectroscopy Examining Committee: Dr. Woo Soo Kim Chair, Assistant Professor Dr. Behraad Bahreyni, Associate Professor, Senior Supervisor Dr. Krishna Vijayaraghavan, Assistant Professor, Supervisor Dr. Babak Rezania, External Examiner, Prongineer R&D Ltd. Date Approved: May 8, 2015 ii Abstract The aim of this research is to build a portable system to perform real-time analysis of waste water samples. Thus, that can significantly improve existing waste water treatment technology. In waste water treatment plant, an important parameter, chemical oxygen de- mand is needed to be measured. The amount of chemical oxygen demand determines the degree of water pollution by organic material. The conventional method for measuring chemical oxygen demand requires sample preparation and pre-treatment using chemicals. These conventional techniques are time consuming and labour intensive.
    [Show full text]
  • Comparison of Colorimetric Analysis, Ion Chromatography, ICP and DGT for Model Phosphorus Solutions and Natural Water Samples
    Comparison of colorimetric analysis, ion chromatography, ICP and DGT for model phosphorus solutions and natural water samples Christoff Van Moorleghem , Erik Smolders, Fien Degryse, Laetitia Six, Elke Vandamme, Roel Merckx Division of Soil and Water Management, Department Earth and Environmental Sciences, Katholieke Universiteit Leuven, Belgium [email protected] Dissolved organic phosphorus in natural water samples is traditionally measured as the difference between total P – measured with colorimetric method (CM) after digestion or ICP – and inorganic P (Pi) – measured with CM or ion chromatography (IC) . Determinations performed in this way are however questionable because of possible hydrolysis during measurement, overestimating the Pi fraction. To obtain a better understanding in the analytical methods for P measurement, the malachite green colorimetric method and ion chromatography were compared to total phosphorus measurement by ICP for two different sets of model P compounds and one set of natural water samples. The first set consisted of 11 model organic phosphorus components and one polyphosphate. In general, neither CM nor IC measured any phosphate for these model organic phosphorus components (less than 4% of total P). However, acetylphosphate and phosphocreatine did hydrolyze during analysis of both IC and CM and 17 up to 100% of the P was detected. We hypothesize that this is explained because of the labile N-P bond for phosphocreatine and the stable resonance form after hydrolysis for acetylphosphate. Phytate, phosphocreatine, ATP, triphosphate and acetylphosphate were also measured using the diffusive gradient in thin films (DGT) technique. After deployment, the adsorbed P on the mixed binding layer was eluted and measured for total P (ICP) and inorganic P (difference of ICP and CM).
    [Show full text]
  • PRE-PUBLICATION NOTICE the EPA Administrator, Michael S. Regan
    PRE-PUBLICATION NOTICE The EPA Administrator, Michael S. Regan, signed the following Final Rule on May 3, 2021, and EPA is submitting it for publication in the Federal Register (FR). It is not the official version of the notice of availability. This document is not disseminated for purposes of EPA's Information Quality Guidelines and does not represent an Agency determination or policy. While we have taken steps to ensure the accuracy of this internet version of this notice, the official version will be published in a forthcoming FR publication, which will appear on https://www.federalregister.gov and on Regulations.gov (https://www.regulations.gov) in Docket No. EPA-HQ-OW-2018-0826. This document is a prepublication version, signed by Administrator Michael S. Regan on 05/03/2021. We have taken steps to ensure the accuracy of this version, but it is not the official version. 6560-50-P ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 136 [EPA-HQ-OW-2018-0826; FRL-10021-59-OW] RIN 2040-AF84 Clean Water Act Methods Update Rule for the Analysis of Effluent AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: The Environmental Protection Agency (EPA) is finalizing changes to its test procedures required to be used by industries and municipalities when analyzing the chemical, physical, and biological properties of wastewater and other environmental samples for reporting under EPA’s National Pollutant Discharge Elimination System (NPDES) permit program. The Clean Water Act (CWA) requires EPA to promulgate these test procedures (analytical methods) for analysis of pollutants. EPA anticipates that these changes will provide increased flexibility for the regulated community in meeting monitoring requirements while improving data quality.
    [Show full text]
  • Video Colorimetry of Single-Chromophore Systems Based on Vector Analysis in the 3D Color Space: Unexpected Hysteresis Loops in Oscillating Chemical Reactions
    Talanta 220 (2020) 121303 Contents lists available at ScienceDirect Talanta journal homepage: www.elsevier.com/locate/talanta Video colorimetry of single-chromophore systems based on vector analysis in the 3D color space: Unexpected hysteresis loops in oscillating chemical reactions Joseph Schell a,b, Sara C. McCauley a, Rainer Glaser a,* a Department of Chemistry, Missouri University of Science and Technology, Rolla, MO, 65409, USA b Department of Chemistry, University of Missouri, Columbia, MO, 65211, USA ARTICLE INFO ABSTRACT Keywords: Colorimetry, the quantitative determination of color, usually of a digital image, has useful applications in diverse Colorimetry areas of research. Many methods have been proposed for translating the RGB data of an image to obtain con­ RGB Color space centration information. Among the many methods for RGB analysis, we focus on the vector projection method Vector projection (VP), which is based on a vector analysis in 3D RGB color space. This method has the major advantages of being Belousov-Zhabotinsky oscillating reaction conceptually intelligible and generalizable to various systems. For solutions with variable concentrations of one Video-based kinetics Hysteresis loops chromophore, we will show that the analysis of the trace in RGB color space allows for a judgment about the reliability of the linear concentration dependence of the chromapostasi parameter. We discuss the theoretical underpinnings of the method in two test cases, a simple dye solution and a titration of an organic acid with phenolphthalein indicator. The VP method was then applied to the Ce-catalyzed Belousov-Zhabotinsky reaction þ with the expectation that the colorimetry would quantify [Ce4 ] oscillations.
    [Show full text]
  • Disposable and Low-Cost Colorimetric Sensors for Environmental Analysis
    International Journal of Environmental Research and Public Health Review Disposable and Low-Cost Colorimetric Sensors for Environmental Analysis Giancarla Alberti 1,*, Camilla Zanoni 1, Lisa Rita Magnaghi 1,2 and Raffaela Biesuz 1,2 1 Department of Chemistry, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy; [email protected] (C.Z.); [email protected] (L.R.M.); [email protected] (R.B.) 2 Unità di Ricerca di Pavia, INSTM, Via G. Giusti 9, 50121 Firenze, Italy * Correspondence: [email protected] Received: 18 October 2020; Accepted: 9 November 2020; Published: 11 November 2020 Abstract: Environmental contamination affects human health and reduces the quality of life. Therefore, the monitoring of water and air quality is important, ensuring that all areas are acquiescent with the current legislation. Colorimetric sensors deliver quick, naked-eye detection, low-cost, and adequate determination of environmental analytes. In particular, disposable sensors are cheap and easy-to-use devices for single-shot measurements. Due to increasing requests for in situ analysis or resource-limited zones, disposable sensors’ development has increased. This review provides a brief insight into low-cost and disposable colorimetric sensors currently used for environmental analysis. The advantages and disadvantages of different colorimetric devices for environmental analysis are discussed. Keywords: colorimetric sensors; disposable devices; low-cost sensors; environmental analysis; in loco analysis 1. Introduction Current attention to environment systems derives from the evidence that people are disrupting the natural processes, and the degree of life quality, or life itself, is being threatened. For example, the rapid population growth and the significant increase in energy consumption are signals of contingent problems.
    [Show full text]
  • Paper-Based Colorimetric Biosensor for Tear Glucose Measurements
    micromachines Article Paper-Based Colorimetric Biosensor for Tear Glucose Measurements Ellen Flávia Moreira Gabriel 1, Paulo Tarso Garcia 1, Flavio Marques Lopes 2 and Wendell Karlos Tomazelli Coltro 1,3,* 1 Instituto de Química, Universidade Federal de Goiás, 74690-900 Goiânia, GO, Brazil; ellenfl[email protected] (E.F.M.G.); [email protected] (P.T.G.) 2 Faculdade de Farmácia, Universidade Federal de Goiás, 74605-170 Goiânia, GO, Brazil; fl[email protected] 3 Instituto Nacional de Ciência e Tecnologia em Bioanalítica (INCTBio), 13083-970 Campinas, SP, Brazil * Correspondence: [email protected]; Tel.: +55-62-3521-1127 Academic Editors: Frank A. Gomez and Carlos D. Garcia Received: 8 February 2017; Accepted: 22 March 2017; Published: 29 March 2017 Abstract: This paper describes a paper-based colorimetric biosensor for measuring glucose concentration levels in human tear samples. Colorimetric biosensors were wax printed on paper platforms and modified with chitosan previously prepared in acetic acid. The proposed device was explored to measure the glucose levels in human tear samples using 3,30,5,50-tetramethylbenzydine (TMB) as the chromogenic reagent. The paper-based colorimetric biosensor exhibited a linear behavior for the glucose concentration range between 0.1 and 1.0 mM. The achieved analytical sensitivity and limit of detection (LOD) were 84 AU/mM and 50 µM, respectively. Moreover, the device provided analytical reliability and no statistical difference when compared to the data recorded with a commercial glucometer. The proof-of-concept of our device was successfully demonstrated by measuring the glucose levels in six tear samples from nondiabetic subjects. In general, the results showed that the colorimetric biosensor has noticeable potential to be used as a powerful tool for tear glucose monitoring, since this fluid offers lower potential interferences, non-invasive sample collection and is pain-free.
    [Show full text]