Arsenic speciation and valence / 中国中药杂志

As arsenic widely exists in nature and has been used in the pharmaceutical preparations, the traditional Chinese medicine(TCM) with arsenic include realgar(As_2S_2 or As_4S_4), orpiment(As_2S_3), and white arsenic(As_2O_3). Among the above representative medicine, the TCM compound formulas with realgar are utilized extensively. Just in Chinese Pharmacopoeia(2020 edition), there are 37 Chinese patent medicines including realgar. The traditional element analysis focuses on the detection of the total amount of elements, which neglects the study on the speciation and valence of elements. The activity, toxicity, bioavailability, and metabolic pathways of arsenic in vivo are closely related to the existence of its form, and different forms of arsenic have different effects on organisms. Therefore, the study on the speciation and valence of arsenic is of great importance for arsenic-containing TCMs and their compound formulas. This paper reviewed four aspects of the speciation and valence of arsenic, including property, absorption and metabolism, toxicity, and analytical assay.

Arsenic exposure in northern Mexican women / Exposición a arsénico en mujeres del norte de México

Abstract: Objective: To describe interindividual metabolism variations and sociodemographic characteristics associated to urinary arsenic, and to estimate the arsenic contamination in water from urinary total arsenic (TAs). Materials and methods: Women (n=1 028) from northern Mexico were interviewed about their sociodemographic characteristics and their urinary concentrations of arsenic species were measured by liquid chromatography. Inorganic arsenic (iAs) in water was estimated from urinary TAs. Results: Women were 20-88 years old. TAs in urine ranged from p10=3.41 to p90=56.93 μg/L; 74% of women had levels >6.4 μg/L. iAs in water varied from p10=3.04 to p90=202.12 μg/L; 65% of women had concentrations >10 μg/L, and 41%, concentrations >25 μg/L. Large variations in iAs metabolism were observed. TAs was significantly negatively associated with age and schooling, and positively with the state of residence. Conclusion: Exposure to iAs is an environmental problem in Mexico. Individual variations in metabolism are a challenge to design prevention and control programs.

Resumen: Objetivo: Describir las variaciones interindividuales del metabolismo y las características sociodemográficas asociadas con el arsénico urinario, así como estimar su contaminación en el agua. Material y métodos. Se entrevistó a 1 028 mujeres del norte de México; por cromatografía de líquidos se midieron los metabolitos urinarios de arsénico y, a partir de ellos, se estimó la concentración en agua. Resultados: Las mujeres tuvieron 20-88 años. El arsénico urinario varió de p10=3.41 a p90=56.93 μg/L; 74% de las mujeres tuvieron niveles >6.4 μg/L. El arsénico en agua varió de p10=3.04 a p90=202.12 μg/L; 65% de las mujeres tenían concentraciones >10 μg/L, y 41%, >25 μg/L. Se observaron amplias variaciones en el metabolismo del arsénico. El arsénico urinario se asoció negativamente con la edad y escolaridad, y positivamente con el estado de residencia. Conclusión: La exposición a arsénico es un problema ambiental en México. Las variaciones individuales en su metabolismo son un desafío para diseñar programas de prevención y control.

Study on simultaneous determination of six arsenic species by HPLC-ICP-MS / 中国中药杂志

This study aims to establish a method for the determination of As B,As C,DMA,As( Ⅲ),MMA and As( Ⅴ) by using HPLC-ICP-MS. A Dioncx Ion PacTMAS7( 4 mm×250 mm) column was used for the HPLC-ICP-MS method. The mobile phase was 100 mmol·L-1 ammonium carbonate-1. 5 mmol·L-1 ammonium dibasic phosphate( gradient elution) at a flow rate of 1 m L·min-1. The injection volume was 10 μL. The linear relationships of As B,As C,DMA,As( Ⅲ),MMA,As( Ⅴ) were good with the concentration of10-500 μg·L-1. The average recovery rates( n = 6) were 105. 7%,100. 5%,102. 9%,105. 7%,100. 2%,92. 69%. The RSD were0. 50%,2. 4%,0. 93%,1. 3%,0. 89%,1. 5%. The precision and repeatability of this method were good. In this study,six forms of arsenic were separated effectively by this method. With methodological validation and sample determination,this method can be used to determine the morphological valence of arsenic in content determination.

Analysis of arsenic speciation in Sepiae Endoconcha and research on its limit standard / 中国中药杂志

Sepiae Endoconcha is a common marine animal medicine,which generally contains high concentration of arsenic( As).The Chinese Pharmacopoeia( 2010 edition,part I) stipulated that the total As content of Sepiae Endoconcha should not exceed 2 mg·kg~(-1),while this limit was revised to 10 mg·kg~(-1) in the 2015 edition. So far,there is no research on the speciation of As in Sepiae Endoconcha,which made it hard to accurately evaluate its security risk. In this study,32 batches of Sepiae Endoconcha from different sources were collected. The safety risk assessment was carried out by determining the total As content and As speciation,inorganic As[As( Ⅲ),As( Ⅴ) ]and organic As( MMA,DMA,As C,As B) by HPLC-ICP-MS,and then the limit standard was discussed. The results showed that As B was the main form of As in Sepiae Endoconcha,followed by DMA and As( Ⅴ) ． Of the 32 batches of Sepiae Endoconcha,9 batches( accounting for 28%) were detected possessing i As. The maximum concentration of As( Ⅲ) was 103. 3 μg·kg~(-1),and the maximum concentration of As( Ⅴ) was 222. 4 μg·kg~(-1). According to the limit of i As in food,18. 75% of the samples exceeded the standard. The results indicate that there is no simple positive correlation between total As and As morphology in Sepiae Endoconcha. Besides,there is a risk in the total As limit,especially after the relaxation of the total As limit. The problem of high i As content caused by pollution and other factors is difficult to regulate. Since the toxicity of inorganic As is much higher than that of organic As,it is of great practical significance to establish inorganic As form limits in Sepiae Endoconcha.

Optimización y validación metodológica de la cuantificación de arsénico por inyección en flujo -generación de hidruros- espectrometría de absorción atómica (IF-GH-EAA) previa derivatización con L-cisteína / Optimization and validation method for arsenic quantification by flow injection-hydride generation - atomic absorption spectrometry (FI-HG-AAS) after L-cysteine derivatization

El arsénico (As) es un contaminante natural que afecta una amplia zona de Argentina. El nivel de As en agua de consumo es utilizado para evaluar la fuente de exposición y en orina para evaluar exposición a este tóxico. El presente trabajo tuvo como objetivo la optimización y validación metodológica de una técnica para la cuantificación de As [As suma = As inorgánico (AsI) + especies metiladas: ácido monometilarsónico (MMA) y ácido dimetilarsónico (DMA)], producto del metabolismo del AsI, por inyección en flujo- generación de hidruros- espectrometría de absorción atómica (IF-GH-EAA), previa derivatización con L-cisteína. La recuperación de las especies estudiadas: AsI (AsIII y AsV), MMA y DMA fue cercana al 100% en todos los casos. Los límites de detección y cuantificación encontrados fueron para agua y orina: 2 y 3 µg/L; 5 y 8 µg/L respectivamente y el rango dinámico de trabajo establecido fue desde 5 a 75 µg/L, permitiendo cuantificar As en muestras de agua cercanos a los estándares internacionales vigentes para valores máximos de As en agua de consumo y en orina en niveles comparables con los establecidos en población laboralmente no expuesta. Esta propuesta metodológica es una alternativa para evaluar la exposición al As en muestras de agua y orina, sin necesidad de utilizar prolongados pre-tratamientos de muestra, de forma más rápida y económica.

Arsenic (As) is a natural contaminant that affects a large area of Argentina. Quantification of As in drinking water has been used to evaluate the source of exposure and As in urine to assess exposure to this toxic. This study aimed to optimize and validate a methodological technique for the quantification of As [As sum = inorganic As (AsI) + methylated species: monometilarsonic acid (MMA) and dimetilarsinic acid (DMA)], product of AsI metabolism by flow injection hydridegeneration-atomic absorption spectrometry (FI-GH-AAS), after derivatization with L-cysteine. The recovery of the studied species: AsI (AsIII and AsV), MMA and DMA was close to 100% in all cases. The limits of detection and quantitation were foundfor water and urine: 2 and 3 µg/L; 5 and 8 µg/L respectively and a linear working range from 5 to 75 µg/L, allowing quantify As in water close to international standards of maximum As values for drinking water and urine samples with levels comparables with those found in people non exposed ocupacionally . This methodology is a valid alternative for assessing exposure to As in water and urine samples without the need of prolonged pre-treatment sample, more quickly and inexpensively.

Estudio de los niveles de contaminaciónpor Arsénico en trabajadores metalúrgicos del departamento de Oruro / Study of the levels of contamination for Arsenic in metallurgical workers of the departament of Oruro

Utilizando el método de digestión ácida yEspectrofotometría de Absorción Atómica con Horno de Grafito, se determinó la concentración de As, en 390 muestras de orina y 384 muestras de cabellos de trabajadores de una empresa fundidora en Oruro. El promedio de As en orina fue 7,826 mg/L (DE=3,548mg/ L con 95% de confianza), mayor al Límite de Tolerancia Biológico (LTB) de 0,1mg/L sugerido por el Instituto Nacional para Salud y Seguridad en el Trabajo (NIOSH). El promedio de As en cabello fue 0,557mg/g (DE=3,741 con 95% de confianza), mucho mayor al LTB de0,001mg/g. El análisis de promedios de concentración en relación a la edad no determinó diferencias representativas. No se encontraron diferencias significativas tanto por la prueba t student (p>0.05)como por el método de Levene’s (F=2.232; p=0.136), en las áreas de trabajo consideradas de exposición directa e indirecta.