Determination of cobalt and tungsten in human urine by inductively coupled plasma mass spectrometry / 中华劳动卫生职业病杂志

Objective: To establish a inductively coupled plasma mass spectrometry method for the determination of trace cobalt and tungsten in human urine. Methods: The authors used 1% nitric acid solution as diluent in October-December 2021, the sample dilution factor and internal standard element were optimized by single factor rotation experiment, and the difference between the working curve and the standard curve was compared. Results: The method uses working curve to determine cobalt and tungsten in urine, the linear range of this method was 0.0~10.0 μg/L, the correlation coefficient was 0.999 9, the detection limits respectively were 0.005 μg/L (cobalt) and 0.09 μg/L (tungsten), the recoveries of samples respectively were 87.0%~100.2% (cobalt) and 89.4%~104.8% (tungsten), the relative standard deviations respectively were 0.4%~4.4% (cobalt) and 0.6%~3.8% (tungsten) . Conclusion: A simple and rapid method for determination of cobalt and tungsten in urine has been established. This method has the advantages of simple operation, high sensitivity, low detection limit and good stability. It is suitable for determination of cobalt and tungsten in urine of all kinds of people.

Quantitative Analysis of Metal Contents in Korean Herbs and Herbal Products to Give Advice for Metal Allergic Patient

BACKGROUND: Herbs have been used worldwide as complementary and alternative medicines. In Korea, herbs for medical purpose are strictly controlled by the Korea Food and Drug Administration (KFDA). But it does not provide standards for metal antigens. OBJECTIVE: This study conducted to identify the metal contents of Korean herbs and herbal products and to give information on counselling metal allergic patient. METHODS: The concentration of three metal allergens with high antigenicity, cobalt (Co), chromium (Cr), nickel (Ni) was quantitatively determined using inductively coupled plasma with a mass spectrometer after nitric acid (HNO₃) digestion. The herbal objects are as follows: 1) ten kinds of herb plants, 2) ten herbal products sold in Korean drugstores, and 3) ten herbal extracts prescribed by Korean herbal doctors. RESULTS: In 30 samples, Ni and Cr were detected in all items. Co was not detected in two drugstore products. CONCLUSION: Although the levels of metal detected in this study were very low relative to international guidelines and KFDA regulations, the herbal preparations contained similar or higher metal levels than known metal-rich foods. It can cause problems when it added to the daily diet and cause deterioration of skin lesions of metal sensitized person.

Fenómeno de Raynaud asociado a ácido nítrico: reporte de un caso / Raynaud's phenomenon associated with nitric acid: Case report

RESUMEN El fenómeno de Raynaud es un trastorno clínico, caracterizado por ataques episódicos de vasoespasmo de arterias y arteriolas periféricas, causando así isquemia tisular de porciones distales del cuerpo, como manos y pies, produciendo cambios en la coloración de la piel como: palidez, cianosis e hiperemia. Se ha asociado la aparición del fenómeno de Raynaud en personas que manipulan solventes orgánicos o herramientas vibratorias por un largo período, incluso se ha descrito que los solventes pueden ser gatilladores de algunas enfermedades inmunológicas como la esclerodermia, sin embargo, hasta donde conocemos no existen reportes de la exposición de compuestos químicos utilizados en la metalurgia, como el ácido nítrico y el desarrollo de enfermedades de espectro esclerodérmico. En el presente artículo se presenta un caso clínico relacionado con la aparición de fenómeno de Raynaud frente a la exposición a compuestos químicos utilizados en la metalurgia, en especial al ácido nítrico.

ABSTRACT The Raynaud phenomenon is a clinical disorder, characterized by episodic attacks of vasospasm of peripheral arteries and arterioles, causing tissue ischemia of distal portions of the body, such as hands and feet, causing changes in skin color such as pallor, cyanosis and hyperemia. The occurrence of the Raynaud phenomenon in people who handle organic sol vents or vibratory tools has been associated for a long time, and it has even been described that the solvents may be triggering some immune diseases such as scleroderma, however, as far as we know there are reports of exposure of chemical compounds used in metallurgy, such as nitric acid and the development of scleroderma-spectrum diseases. This article presents a clinical case related to the appearance of Raynaud s phenomenon against exposure to chemical compounds used in metallurgy, especially nitric acid.

Characteristics of Emergency Medical Service Provider Responded Chemical, Biological, Radiological, and Nuclear Incidents: Pilot Analysis of National Emergency Medical Service Rescue Records

PURPOSE: The aim of this study was to evaluate the characteristics of Emergency Medical Service (EMS) provider responded chemical, biological, radiological, and nuclear (CBRN) incidents in Korea. METHODS: Nationwide EMS rescue records from Jan 2012 to Dec 2014 were analyzed. All EMS rescue records were integrated according to the unique accident ID. Cases related to animal rescue, hive removal, and suicide-related were excluded. CBRN-associated keywords were extracted by literature review and pilot survey. In-depth review of cases containing CBRN-associated keywords in the activity summary were conducted by trained emergency medical technicians, and predefined information was abstracted. Descriptive analyses were performed to characterize the EMS provider responded CBRN incidents. RESULTS: A total of 1,571,293 cases were included, and 1,335,205 cases had a unique accident ID; 515,417 cases were excluded because of their association with animal rescue, hive removal, and suicide attempts; 19,663 cases contained CBRN-associated keywords in the activity summary, and in-depth review identified 1,862 cases as CBRN incidents. Among them 1,856 cases were chemical incidents, and 6 cases were radiological incidents; 144 cases were resulted to victims. In chemical incidents, ammonia, hydrogen chloride, sulfuric acid, hydrogen fluoride, and nitric acid were the top 5 toxic substances. In chemical incidents with victims, the proportion of explosion/implosion, and suffocation in sealed space was more prevalent than chemical incidents without victims. Median scene time of all CBRN incidents was 41 minutes (interquartile range 18.0-57.0). CONCLUSION: We evaluated the characteristics of CBRN incidents responded by EMS in Korea.

Superação de dormência em sementes de Bombax malabaricum D. C. (Malvaceae) / Dormancy breaking in seeds of Bombax malabaricum D. C. (Malvaceae)

RESUMOA espécie Bombax malabaricum, popularmente conhecida por paineira-vermelha, apresenta metabólitos secundários de interesse medicinal. Como outras espécies da família Malvaceae, suas sementes possuem dormência tegumentar, o que dificulta sua propagação sexuada. Assim, o presente trabalho objetivou superar a dormência de sementes de B.malabaricum por métodos físicos e químicos. Os métodos utilizados na escarificação mecânica foram: abrasão do tegumento com lixa e corte com tesoura na região oposta ao hilo. Para a escarificação química foram utilizados: ácido clorídrico (HCl), ácido nítrico (HNO3), ácido sulfúrico (H2SO4), hidróxido de sódio (NaOH) e hidróxido de potássio (KOH) por um período de 30 minutos. Também houve imersão de sementes em 40 mg L-1 de GA3 pelo mesmo período. Foram utilizadas quatro repetições por tratamento, constituídas de 25 sementes por placa e conduzidas em Câmara de Germinação. Os dados obtidos foram utilizados para o cálculo da Germinabilidade, Índice de Velocidade de Germinação, Tempo Médio de Germinação, e Porcentagem de Sementes Deterioradas. O HNO3 mostrou-se como o melhor tratamento na variável Germinabilidade (83,5%), seguido do HCl (71,5%) e das técnicas de escarificação mecânica, com lixa (71,5%) e tesoura (67,5%). O HNO3também apresentou o menor número de sementes deterioradas (3,5%); o H2SO4 foi o tratamento que mais causou danos às sementes (36,5%).

ABSTRACTThe species Bombax malabaricum, popularly known as red-cotton tree, presents secondary metabolites of medicinal interest. Like other species of the Malvaceae, their seeds have tegumentary dormancy, which hinders their sexual propagation. Thus, this study aimed to break the dormancy of B. malabaricum through physical and chemical strategies. For mechanical scarification of the seeds it were employed: abrasion of the tegument with sandpaper and cut with scissors in the region opposite to the hilum. For chemical scarification: hydrochloric acid (HCl), nitric acid (HNO3), sulphuric acid (H2SO4), sodium hydroxide (NaOH) and potassium hydroxide (KOH) for a period of 30 minutes. The seeds were also subjected to immersion in 40 mg L-1 of GA3 for the same period. Four replicates of 25 seeds were used for each treatment and then they were conducted for calculation in a B.O.D. germination Chamber. The results obtained were applied in order to calculate: Germination, Germination Speed Index, Average Time of Germination and Percentage of Damaged Seeds. The HNO3proved to be the best treatment in the Germination trials (83.5%), followed by the HCl (71.5%) and the mechanical scarification techniques with sandpaper (71.5%) and scissors (67.5%). The HNO3 also showed the lowest percentage of damaged seeds (3.5%); The H2SO4 was the treatment that caused more damage to the seeds (36.5%).

Dilute acid pretreatment and enzymatic hydrolysis of sorghum biomass for sugar recovery—A statistical approach.

Sorghum is one of the commercially feasible lignocellulosic biomass and has a great potential of being sustainable feedstock for renewable energy. As with any lignocellulosic biomass, sorghum also requires pretreatment which increases its susceptibility to hydrolysis by enzymes for generating sugars which can be further fermented to alcohol. In the present study, sorghum biomass was evaluated for deriving maximum fermentable sugars by optimizing various pretreatment parameters using statistical optimization methods. Pretreatment studies were done with H2SO4, followed by enzymatic saccharification. The efficiency of the process was evaluated on the basis of production of the total reducing sugars released during the process. Compositional analysis was done for native as well as pretreated biomass and compared. The biomass pretreated with the optimized conditions could yield 0.408 g of reducing sugars /g of pretreated biomass upon enzymatic hydrolysis. The cellulose content in the solid portion obtained after pretreatment using optimised conditions was found to be increased by 43.37% with lesser production of inhibitors in acid pretreated liquor.

Examen químico-metalográficocon ácido nítrico en carroceríasy chasis en acero de vehículos / Chemical-metallographic test with nitric acid on the vehicle bodyand chassis of steel / Exame químico e metalográfico com ácido nítriconas carrocerias e no chassi em aço dos veículos

La alteración de sistemas de identificación de vehículos serealiza utilizando lijas o esmeril, y posteriormente se sobreponeuna identificación alfanumérica distinta, con elobjetivo de que no se pueda verificar su origen o propiedad,y se dificulte su rastreo. El ataque químico se reconocecomo la técnica más sensible para recuperar númerosseriales que han sido alterados; en este trabajo se propuso evaluar la efectividad del ácido nítrico (HNO3) 3,15 M parael revelado de números seriales alterados en superficies de carrocerías y chasis con aleaciones en acero y carbonobajo y medio, respectivamente. Se realizaron cuatro pruebas:(i) carrocería, marcación en taco y borrado con pulidora; (ii)carrocería, marcación en lápiz eléctrico y borrado manual;(iii) chasis, marcación en taco y borrado manual, y (iv) chasis, marcación manual en taco y borrado con pulidora. En todas las pruebas realizadas, las marcas borradas se recuperaron en pocos segundos, con definición y contraste. Lo anteriorcoloca el uso de este reactivo como una técnica rápida y confiable para el estudio químico-metalográfico tendiente a larecuperación de marcas adulteradas en aleaciones de acero.

The alteration of a vehicle identification characteristics is carried out with the use of emery and sandpaper to erase the information in order to subsequently superimpose different numeric or alphanumeric codes, thus preventing the verification of its former origin or ownership and hindering its tracking. Chemical attack has been recognized as the most sensitive technique to retrieve altered serial numbers,and this article was aimed at assessing the effectiveness of nitric acid (HNO3) 3.15 M in revealing them on body and chassis surfaces with steel, low-carbon and medium carbon steel alloys respectively. Four tests were performed: (i)Bodywork: marking, and erasing with grinding machine,(ii) bodywork: marking with electric pen, and manual deletion;(iii) chassis: marking, and manual deletion, and (iv)manual marking, and erasing with grinding machine. In all tests carried out, erased markings were retrieved in a fewseconds, with definition and contrast. According to the above, the use of this reactive is acknowledged as a fastand reliable technique for chemical-metallographic tests leading to the retrieval of tempered marks on steel alloys.

A alteração dos sistemas da identificação dos veículos é feito usando lixas ou esmeril, e depois se sobrepõe uma identificação alfanumérica diferente, com o objetivo de que sua origem ou propriedade não podem ser verificadas, e torna-se difícil seu rastreamento. O ataque químico é reconhecido como a técnica mais sensível para recuperar os números seriais que foram alterados; neste trabalho a proposta era avaliar a eficácia do ácido nítrico (3 HNO3) 3.15 ms para o revelado dos números dos seriais alterados nas superfícies das carrocerias e dos chassis com as ligas no aço e no carbono baixo e médio, respectivamente. Quatro testes foram feitos:(i) carroceria, marcação em taco e apagado com polidor; (ii)carroceria, marcação em lápis elétrico e apagado manual; (iii)chassi, marcação em taco e apagado manual, e (iv) chassi,marcação manual em taco e apagado com polidor. Em todos os testes feitos, as marcas apagadas foram recuperadas em poucos segundos, com a definição e os contrastes. O precedente coloca o uso deste reativo como uma técnica rápida e confiável para o estudo químico e metalográfico que visa à recuperação das marcas adulteradas nas ligas de aço.

Comparative analysis between diatom nitric acid digestion method and plankton 16S rDNA PCR method / 法医学杂志

OBJECTIVE@#To compare and explore the application value of diatom nitric acid digestion method and plankton 16S rDNA PCR method for drowning identification.@*METHODS@#Forty drowning cases from 2010 to 2011 were collected from Department of Forensic Medicine of Wenzhou Medical University. Samples including lung, kidney, liver and field water from each case were tested with diatom nitric acid digestion method and plankton 16S rDNA PCR method, respectively. The Diatom nitric acid digestion method and plankton 16S rDNA PCR method required 20 g and 2 g of each organ, and 15 mL and 1.5 mL of field water, respectively. The inspection time and detection rate were compared between the two methods.@*RESULTS@#Diatom nitric acid digestion method mainly detected two species of diatoms, Centriae and Pennatae, while plankton 16S rDNA PCR method amplified a length of 162 bp band. The average inspection time of each case of the Diatom nitric acid digestion method was (95.30 +/- 2.78) min less than (325.33 +/- 14.18) min of plankton 16S rDNA PCR method (P < 0.05). The detection rates of two methods for field water and lung were both 100%. For liver and kidney, the detection rate of plankton 16S rDNA PCR method was both 80%, higher than 40% and 30% of diatom nitric acid digestion method (P < 0.05), respectively.@*CONCLUSION@#The laboratory testing method needs to be appropriately selected according to the specific circumstances in the forensic appraisal of drowning. Compared with diatom nitric acid digestion method, plankton 16S rDNA PCR method has practice values with such advantages as less quantity of samples, huge information and high specificity.

A Case of Chemical Pneumonitis with Gastrointestinal Disturbance Caused by Nitric Acid Inhalation

Nitric acid is a typical strong acid that is colorless, corrosive, and flammable. It is often used for industrial purposes, such as refining, metal cleaning, and electroplating. In Korea, some cases of chemical pneumonitis from nitric acid poisoning have been reported, but to our knowledge, there have been no reports of diarrhea caused by nitric acid poisoning. A 42-year-old man visited a nearby hospital because of continuous diarrhea, coughing, and dyspnea after inhaling nitric acid fumes at his workplace the previous day. He was transferred to our hospital and admitted to the intensive care unit. He showed tachypnea and hypoxemia in our emergency department. Initial chest radiographs showed diffuse interstitial infiltrates and ground glass opacity in both lungs. The patient showed improvements in clinical symptoms and on chest radiographs after receiving oxygen and mechanical ventilation, antibiotics, and systemic glucocorticoid therapy. After 20 days he was discharged and showed no symptoms and sequelae on his 1-year follow-up.

Protective effects of shengmai san and its three fractions on cerebral ischemia-reperfusion injury / 中国天然药物

AIM@#To investigate the antioxidant and anti-inflammatory effects of Shengmai San (SMS) and its ethyl acetate extract (SEa), n-butanol extract (SBu), and aqueous extract (SWe), and clarify the material base of SMS and the roles played by its fractions.@*METHODS@#A mouse model of transient forebrain ischemia/reperfusion (I/R) by means of common carotid artery occlusion (CCAO) was used to investigate the effects of SMS and its three fractions. Histopathological damage, blood-brain barrier disruption, and antioxidant and inflammation-related parameters, including malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), myeloperoxidase (MPO), nitric oxide (NO), tumor necrosis factor-α (TNF-α) were measured. The chemical constituents of each fraction were identified by LC-MS.@*RESULTS@#Eighteen lignans in SEa, and thirteen steroidal glycosides and ginsenosides in SBu were determined. SMS significantly inhibited I/R induced formation of histological injury and cerebral MPO activity. SMS showed the strongest antioxidant and anti-inflammatory effects against the I/R-caused injuries. SEa showed higher antioxidant activity than the other two fractions and SBu has a slightly stronger inhibition on the productions of NO and TNF-α.@*CONCLUSION@#SMS as a whole had the most effective protection against cerebral I/R-caused injuries compared with its fractions, which inferred that it contains different groups of compounds that contribute together to its protective effect.

Apoptosis and oxidative stress in infants and children with convulsions

Apoptosis and oxidative stress will be studied. The study included 150 pediatric patients admitted to Assiut University children Hospital because of convulsions. Their ages ranged from 6 M- 12y. The study also included 10 apparently healthy children of matchable age as controls. All cases and controls had the following investigations done: complete blood count, serum calcium, glucose, urea and creatinine. Nitric oxide [NO], Total thiobarbituric acid reactive species [TBARS], soluble fas, 5 hydroxytryptamine [5HT], gamma aminobutyric acid [GAB4] and DNA fragmentation percentage. All cases had an EEG done on admission. This study showed that apoptois and oxidative stress were significantly higher in cases than controls. Cases with prolonged and/or focal convulsions showed significantly higher % DNA fragmentation. Cases with simple febrile convulsions, higher degree of rise of temperature and shorter duration of convulsion [<5 minutes] showed significantly higher % DNA fragmentation. Younger cases [<2years] showed significantly higher degree of rise of temperature, oxidative stress and % DNA fragmentation. Cases with [temperature > 39 Degree C] also showed significantly higher % DNA fragmentation and significantly lower GABA levels. Correlation study showed significant positive correlation between % DNA fragmentation and rise of temperature

Conclusion and Recommendations. From this study, it can he concluded that the so called simple febrile convulsions showed significantly higher apoptosis

Recommendations: It is recommended that EEG monitoring should be done during the convulsion to be able to correlate the EEG, findings with the type of convulsion

The Comparison of Plankton Detection by Two Analysis Methods in the Seawater of Gageo Island / 대한법의학회지

The acid digestion method for extracting diatoms has been widely used to confirm death by drowning, but its reliability is still disputed because some diatoms can be destroyed during the extraction process due to treatment with strong acid and heat. There is a need to develop an efficient and reliable digestive method to overcome the limitation of the present analytical procedure. In this study, the reliability and efficacy of quantitative and qualitative diatom analysis from seawater by an enzymatic digestion method was evaluated. We confirmed the merit of the enzymatic method that used proteinase K instead of nitric acid in the conventional method. As a result, the enzymatic method showed a higher recovery ratio and better preservation of the diatom structure, which is essential for quantitative (diatom density) and qualitative (species) interpretation of diatom analysis. This result indicates that the enzymatic method can replace the conventional acid digestion method to confirm cases of death by drowning since it is more reliable and yields conclusive results.

Anesthetic management of a patient with nitric acid inhalation injury for extracorporeal membrane oxygenation / 대한마취과학회지

No abstract available.

Molecular characterization of glutathione S-transferase, endothelial nitric oxide synthase and Vitamin D receptor genes in breast cancer cases

Enzymes of the Glutathione S-transferase system [GST] modulate the effects of exposure to several cytotoxic and genotoxic agents. Nitric oxide [NO] is constitutively synthesized in the endothelium by endothelial nitric oxide synthase [eNOS] and acts as a pleiotropic regulator involved in carcinogenesis. Vitamin D levels may influence breast cancer development. The vitamin D receptor [VDR] is a crucial mediator for the cellular effects of vitamin D and additionally interacts with other cell-signaling pathways that influence cancer development. To check for the association of polymorphisms of GST, eNOS3 and VDR genes with the susceptibility and severity of breast cancer in Egyptian cases. This work included 100 cases with breast cancer and 100 healthy individuals. The mean age of cases was 48.31 +/- 11.40 years. They included 100 females. DNA was amplified using PCR-RFLP for detection of polymorphisms related to eNOS3 and VDR, also DNA was amplified using PCR-SSP for detection of polymorphisms related to GST and calculating the odds ratios and their 95% confidence intervals. Total cases showed high significant frequency of eNOS3[-786] CC [P<0.05, OR=18.58] genotypes, GSTT1 [null] [OR = 2.68; CI 95%=1.51-4.75; p=0.001]. These were considered risk genotypes for disease susceptibility. On the other hand, total cases showed low significant frequency with homozygosity for eNOS3[-786] TT [P=0.01] and the GSTT1 gene was present in 42.0% of the cancers and in 66.0% of controls [OR = 0.37; CI 95%= 0.21-0.66; p=0.001]. These may be considered low risk genotypes. No significant difference in frequencies of null and present genotypes of GSTM1 and VDR FOKI in total cases compared to controls. Polymorphisms related to eNOS3[-786], GSTT1 and VDR FOKI genes may be considered genetic markers for BC among Egyptian cases. This may have potential impact on family counselling as well as future management plans

Choose of heavy metals pollution biomonitors: a critic of the method that uses sediments total metals concentration as the benchmark

The study aimed to come up with a list of specific macroalgae species, which could be used to biomonitor specific metal elements in the coastal waters of East Africa. Water extraction, EDTA, aqua regia extraction and optimized BCR 3-step sequential extracts were used to mimic bioavailable metals under various environmental conditions. The results indicated that Viva lactuca could be used as a biomonitor to predict BCR 3-step sequential bioavailable Al, Cd, Co, Fe, Mn, Zn and Ni whereas Sargassum species could be used as a biomonitor for BCR 3-step sequential bioavailable Co, Cu, Fe, Mn and Zn. In Sargassum spp. only Co showed significant correlation with concentration in sediment's aqua regia extracted metals whereas in Viva lactuca only Al, Co, Cu and Fe showed significant correlation with total metals extracted through aqua regia procedure. This study therefore recommends the use of Viva lactuca and Sargassum for biomonitoring of Al, Cd, Co, Fe, Mn, Zn, Ni and Co, Cu, Fe, Mn, Zn respectively. The study recommends the use of labile fraction of BCR sequential extraction for screening of macroalgae to be used for heavy metal pollution monitoring in East Africa region

Intoxicación por ácido nítrico: presentación de caso / Nitric acid Poisoning: case report

El ácido nítrico (HNO3) es un líquido corrosivo que al contacto con agentes reductores genera óxidos del nitrógeno, los cuales son responsables de la intoxicación inhalatoria. Presentamos dos casos de intoxicación por inhalación gases de ácido nítrico secundarios a exposición laboral. Los hallazgos imaginológicos fueron similares en ambos casos y compatibles con el síndrome de dificultad respiratoria del adulto: infiltrados alveolares, bilaterales y difusos en la radiografía de tórax y patrón en empedrado en la tomografía. Uno de los pacientes falleció y el otro evolucionó de manera satisfactoria después del manejo con N-acetil cisteína y ventilación mecánica. El diagnóstico de intoxicación por ácido nítrico fue hecho basado en el antecedente de exposición de estos pacientes y en la evolución de los hallazgos radiológicos.

Quantitative Exposure Assessment of Various Chemical Substances in a Wafer Fabrication Industry Facility

OBJECTIVES: This study was designed to evaluate exposure levels of various chemicals used in wafer fabrication product lines in the semiconductor industry where work-related leukemia has occurred. METHODS: The research focused on 9 representative wafer fabrication bays among a total of 25 bays in a semiconductor product line. We monitored the chemical substances categorized as human carcinogens with respect to leukemia as well as harmful chemicals used in the bays and substances with hematologic and reproductive toxicities to evaluate the overall health effect for semiconductor industry workers. With respect to monitoring, active and passive sampling techniques were introduced. Eight-hour long-term and 15-minute short-term sampling was conducted for the area as well as on personal samples. RESULTS: The results of the measurements for each substance showed that benzene, toluene, xylene, n-butyl acetate, 2-methoxyethanol, 2-heptanone, ethylene glycol, sulfuric acid, and phosphoric acid were non-detectable (ND) in all samples. Arsine was either "ND" or it existed only in trace form in the bay air. The maximum exposure concentration of fluorides was approximately 0.17% of the Korea occupational exposure limits, with hydrofluoric acid at about 0.2%, hydrochloric acid 0.06%, nitric acid 0.05%, isopropyl alcohol 0.4%, and phosphine at about 2%. The maximum exposure concentration of propylene glycol monomethyl ether acetate (PGMEA) was 0.0870 ppm, representing only 0.1% or less than the American Industrial Hygiene Association recommended standard (100 ppm). CONCLUSION: Benzene, a known human carcinogen for leukemia, and arsine, a hematologic toxin, were not detected in wafer fabrication sites in this study. Among reproductive toxic substances, n-butyl acetate was not detected, but fluorides and PGMEA existed in small amounts in the air. This investigation was focused on the air-borne chemical concentrations only in regular working conditions. Unconditional exposures during spills and/or maintenance tasks and by-product chemicals were not included. Supplementary studies might be required.

Validação do método titulométrico para determinação de etanol em sangue utilizando ácido nítrico 54 e ácido sulfúrico concentrado / Validation of chemical titration for blood-alcohol determination using nitric acid 54 and concentrated sulfuric acid

A causa da maioria dos acidentes automobilisticos tern sido há muito associada ao consumo de álcool e, visando diminuir esses acidentes, os países tem estabelecido limites de alcoolemia para os condutores. A determinação da alcoolemia tem se tornado importante para fins de aprendizagem, clínico-legais, administrativos, e particularmente no cumprimento da lei, com aplicação específica nas violações automobilísticas, podendo subsequentemente assumir relevância forense como evidência de intoxicação. A quantificação sanguínea de etanol por titulometria é bastante utilizada, fornecendo boa correlação linear, sensibilidade, precisão, exatidão, baixo custo e relativa facilidade de execução. Devido à proibição da venda de ácido nítrico concentrado pela Polícia Federal, Polfcia Civil e Exército Brasileiro, o objetivo desse trabalho foi avaliar as características de desempenho do método utilizando outros reagentes em substituição ao ácido nítrico concentrado, com isso garantindo a eficiência na quantificação do etanol em sangue. Os melhores resultados foram obtidos com ácido nítrico 54%, necessitando apenas de ajustes em relação aos volumes utilizados na técnica original. A solução sulfocrômica mostrou-se de difícil manipulação em função de sua viscosidade. Os resultados demonstraram que o método modificado apresentou linearidade, precisão e exatidão, de acordo com a resolução especificada pela ANVISA, Agência Brasileira Regulatória.

All over the world, the main cause of traffic accidents has been associated to alcohol use. In many countries, laws have been introduced to control drink-driving, reducing accidents. Accurate blood-alcohol determination has become increasingly important for learning, clinical, forensic and administrative purposes. It is required in law enforcement, with specific application to automobile traffic violations. Blood ethanol determinations carried out for diagnostic purposes can subsequently assume forensic relevance as evidence of intoxication. Blood-alcohol determinations by chemical titration has been used for many years, it supplies good linear correlation, sensitivity, precision, accuracy, low cost and relative easiness of execution. Due to sale prohibition of concentrated nitric acid by Federal Policy, Civil Policy and Brazilian Army is the aim of this work to carry through assays with other reagents in substitution to that one, to evaluate its performance characteristics and to guarantee its efficiency. The best ones resulted had been gotten with nitric acid 54%, needing only volumes adjustments beside original technique. Chromic acid solution prepared with concentrated sulfuric acid had viscosity of difficult manipulation. Based on the results, the method presented good linear correlation, was accurate and precise according to specific resolution from ANVISA, the Brazilian Regulatory Agency.

Recovery of silver residues from dental amalgam

Dental amalgam residues are probably the most important chemical residues generated from clinical dental practice because of the presence of heavy metals among its constituents, mainly mercury and silver. OBJECTIVE: The purpose of this study was to develop an alternative method for the recovery of silver residues from dental amalgam. MATERIAL AND METHODS: The residue generated after vacuum distillation of dental amalgam for the separation of mercury was initially diluted with 32.5 percent HNO3, followed by precipitation with 20 percent NaCl. Sequentially, under constant heating and agitation with NaOH and sucrose, the sample was reduced to metallic silver. However, the processing time was too long, which turned this procedure not viable. In another sequence of experiments, the dilution was accomplished with concentrated HNO3 at 90ºC, followed by precipitation with 20 percent NaCl. After washing, the pellet was diluted with concentrated NH4OH, water and more NaCl in order to facilitate the reaction with the reducer. RESULTS: Ascorbic acid was efficiently used as reducer, allowing a fast reduction, thus making the procedure viable. CONCLUSIONS: The proposed methodology is of easy application and does not require sophisticated equipment or expensive reagents.