Isolation of methylmercury using distillation and anion-exchange chromatography for isotopic analyses in natural matrices.
Anal Bioanal Chem
; 412(3): 681-690, 2020 Jan.
Article
en En
| MEDLINE
| ID: mdl-31834449
ABSTRACT
The development of mercury (Hg) stable isotope measurements has enhanced the study of Hg sources and transformations in the environment. As a result of the mixing of inorganic Hg (iHg) and methylmercury (MeHg) species within organisms of the aquatic food web, understanding species-specific Hg stable isotopic compositions is of significant importance. The lack of MeHg isotope measurements is due to the analytical difficulty in the separation of the MeHg from the total Hg pool, with only a few methods having been tested over the past decade with varying degrees of success, and only a handful of environmentally relevant measurements. Here, we present a novel anion-exchange resin separation method using AG 1-X4 that further isolates MeHg from the sample matrix, following a distillation pretreatment, in order to obtain ambient MeHg stable isotopic compositions. This method avoids the use of organic reagents, does not require complex instrumentation, and is applicable across matrices. Separation tests across sediment, water, and biotic matrices showed acceptable recoveries (98 ± 5%, n = 54) and reproducible δ202Hg isotope results (2 SDs ≤ 0.15) down to 5 ng of MeHg. The measured MeHg pools in natural matrices, such as plankton and sediments, showed large deviations from the non-speciated total Hg measurement, indicating that there is an important isotopic shift during methylation that is not recorded by typical measurements, but is vital in order to assess sources of Hg during bioaccumulation. Graphical abstract.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Contaminantes Químicos del Agua
/
Monitoreo del Ambiente
/
Cromatografía por Intercambio Iónico
/
Compuestos de Metilmercurio
Tipo de estudio:
Evaluation_studies
Límite:
Animals
Idioma:
En
Revista:
Anal Bioanal Chem
Año:
2020
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
ALEMANHA
/
ALEMANIA
/
DE
/
DEUSTCHLAND
/
GERMANY