The concentration levels and congener profiles of polychlorinated biphenyls (PCBs), pentachlorobenzene (PeCBz), and hexachlorobenzene (HxCBz) were assessed in commercially available organic pigments. Among the azo-type pigments tested, PCB-11, which is synthesized from 3,3'-dichlorobendizine, and PCB-52, which is synthesized from 2,2',5,5'-tetrachlorobendizine, were the major congeners detected. It is speculated that these were byproducts of chlorobendizine, which has a very similar structure. The total PCB concentrations in this type of pigment ranged from 0.0070 to 740 mg/kg. Among the phthalocyanine-type pigments, highly chlorinated PCBs, mainly composed of PCB-209, PeCBz, and HxCBz were detected. Their concentration levels ranged from 0.011 to 2.5 mg/kg, 0.0035 to 8.4 mg/kg, and 0.027 to 75 mg/kg, respectively. It is suggested that PeCBz and HxCBz were formed as byproducts and converted into PCBs at the time of synthesizing the phthalocyanine green. For the polycyclic-type pigments that were assessed, a distinctive PCB congener profile was detected that suggested an impact of their raw materials and the organic solvent used in the pigment synthesis. PCB pollution from PCB-11, PCB-52, and PCB-209 pigments is of particular concern; therefore, the monthly variations in atmospheric concentrations of these pollutants were measured in an urban area (Sapporo city) and an industrial area (Muroran city). The study detected a certain level of PCB-11, which is not included in PCB technical mixtures, and revealed continuing PCB pollution originating from pigments in the ambient air.
This study reports the concentrations and congener partners of polychlorinated biphenyls (PCBs) in commercially available paints. Polycyclic-type pigments containing dioxazine violet (pigment violet (PV) 23, PV37) and diketopyrrolopyrrole (PR254, PR255) were found to contain PCB-56, PCB-77, PCB-40, PCB-5, and PCB-12, and PCB-6, PCB-13, and PCB-15, respectively, as major congeners. Dioxazine violet is contaminated with by-products during synthesis from o-dichlorobenzene, which is used as a solvent during synthesis, and diketopyrrolopyrrole is contaminated with by-products during synthesis from p-chlorobenzonitrile. The concentration of PCBs in paint containing PV23 or PV37 was 0.050-29 mg/kg, and toxic equivalency (TEQ) values ranged 1.1-160 pg-TEQ/g. The concentration of PCBs in paint containing PR254 or PR255 was 0.0019-2.4 mg/kg. Naphthol AS is an azo-type pigment, and PCB-52 was detected in paint containing pigment red (PR) 9 with 2,5-dichloroaniline as its source. PCB-146, PCB-149, and PCB-153 were identified from paint containing PR112 produced from 2,4,5-trichloroaniline, as major congeners. These congeners have chlorine positions similar to aniline, indicating that these congeners are by-products obtained during the synthesis of pigments. The concentrations of PCBs in paints containing PR9 and PR112 were 0.0042-0.43 and 0.0044-3.8 mg/kg, respectively. The corresponding TEQ for PR112 was 0.0039-8.6 pg-TEQ/g.
Since the hydride generation (HG) method was first introduced by Holak 1 to atomic absorption spectrometry, HG-AAS has been widely used for the determination of arsenic in biological and environmental samples.2,3 As the HG-AAS method is based on the evolution and transport of arsine, careful optimization of experimental parameters and minimization of interferences are required for obtaining reliable results. 2 In the hydride generation procedure using tetrahydroborate(III), control of pH of the reduction solution was used to the differential determination of As(III) and As(V) 4-7 , based on the fact that As(III) can react with tetrahydroborate(III) at higher pH than As(V). Solvent extraction of As(III) followed by back-extraction procedure was also used before hydride generation. 8 Arsenic speciation procedures in environmental and biological samples by hydride generation followed by AAS, ICP-AAS and ICP-MS have been summarized in a review. 9 Many methods have also been reported for the determination of arsenic without hydride generation, such as neutron activation analysis 2,10 , voltammmetry 2,11 , spectrophotometry 12 , graphite-furnace atomic absorption spectrometry (GFAAS). 2,13-17 GFAAS is one of the most reliable techniques; in it, the loss of arsenic during the charing cycle of the graphite atomizer is prevented by matrix modification with salts of nickel or palladium. 2 The GFAAS procedure for the determination of trace amounts of arsenic was based on the solvent extraction followed by direct determination or determination after back extraction to an aqueous solution. Ammonium pyrrolidinedithiocarbamate (APDC) 13,15 , sbutyl dithiophosphate 14 and potassium iodide 16 were used for the selective extraction of As(III). Total arsenic(III,V) was then extracted after reduction of As(V) to As(III). The preconcentration of As(V) on a membrane filter as an ion associate of arsenomolybdate and tetraphenylphosphonium ions was also proposed; 17 in this, total As(III,V) was extracted after oxidation of As(III) to As(V).In a previous work we reported a solid phase extraction method using a finely divided ion-exchange resin and APDC for the GFAAS determination of trace amounts of cadmium and lead in water. 18 The advantages of the fine resin particles are: 1) they have hydrophilic properties and can be dispersed throughout the bulk solution in a short time; 2) they have a large surface area of hydrophobic properties and can rapidly extract the species of hydrophobic properties, regardless of the ionic strength of the bulk solution; 3) they can be collected on a membrane filter from the bulk solution by filtration and dispersed in a small volume of solution to make a suspension which is directly subjected to the GFAAS. In this work, a combination of finely divided ion-exchange resin and APDC was applied to preconcentration and GFAAS determination of trace amounts of arsenic in water. Department of Materials Science and Technology, Faculty of Science and Technology, Hirosaki University, Hirosaki 036, JapanA preconcent...
Graphite-furnace atomic absorption spectrometry (GFAAS) is one of the most widely used techniques for the determination of trace elements in water. However, its sensitivity for cadmium and lead is not sufficient for a direct determination of these elements in drinking water. So far, many techniques have been used for the enrichment of trace elements in water samples. One of the most important conditions of the enrichment techniques is simple connection to the subsequent determination techniques. When the desired trace elements can be quantitatively extracted on a small amount of fine particles, a method based on the collection of particles by filtration, the preparation of a suspension in a small volume and the determination by suspensionintroduction GFAAS is favorable. Chelating ionexchange resins 1-7 and ion-exchange resins 8 and activated carbon 9-12 with complexing agents have been used for this purpose. Another technique was recently reported in which a part of the resin thin layer was cut and inserted in a cuvette for the determination by electrothermal AAS. 13The aim of this work was to develop a simple preconcentration method for the determination of cadmium and lead in tap water with the combined use of a finely divided ion-exchange resin and APDC. Fine resin particles are well suited for the rapid collection of the desired trace elements from a large sample of aliquots. 8 Since the ion-exchange resin particles have both hydrophilic and hydrophobic properties, they can act as a hydrophilic organic solid in the bulk solution, and can extract species with hydrophobic properties. APDC was selected for the simultaneous extraction of cadmium and lead on the resin particles. The proposed method was applied to the determination of cadmium and lead in tap water supplied to our laboratory. Experimental ApparatusA Hitachi Zeeman-effect GFAAS (Model Z-8270) equipped with an auto-sampler (Model SSC-300) was used for measuring the atomic absorption of cadmium and lead. The instrumental operating conditions are summarized in Tables 1 and 2. A Toyo KG-25 filter holder with a membrane filter of cellulose nitrate (0.45 mm pore size, 25 mm in diameter) was used for collecting the resin particles by filtration under suction. A Branson Ultrasonic Cleaner B-42 was used for preparing the resin suspension. ReagentsAll reagents used were of analytical grade. A Yamato Model WAR-30 and a WB-21 Auto-Still were employed to purify the water used; the water was first passed through a reverse-osmosis membrane and then A rapid and simple preconcentration method based on the combined use of ammonium pyrrolidinedithiocarbamate (APDC) and a finely divided anion-exchange resin has been described for the determination of trace amounts of cadmium and lead by graphite-furnace atomic absorption spectrometry (GFAAS). Cadmium-and lead-APDC complexes were extracted simultaneously on the resin at pH 6. The resin particles holding the cadmium-and lead-APDC complexes were separated by filtration and dispersed in 1.0 ml of 0.1 mol l -1 hydrochloric ...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.