Enzymatic probe sonication as a tool for solid-liquid extraction for total selenium determination by electrothermal-atomic absorption spectrometry.
A new fast and reproducible approach is described for the application of the enzymatic probe sonication (EPS) methodology [J.L. Capelo, P. Ximénez-Embún, Y. Madrid-Albarrán, C. Cámara, Anal. Chem. 76 (2004) 233-237] for total selenium determination by electrothermal atomic absorption spectrometry, ET-AAS. Ni(NO3)2 and Pd(NO3)2 were studied as matrix modifiers in conjunction with H2O2, being best results obtained with Pd(NO3)2 plus H2O2. The presence of H2O2 as matrix modifier increases up to 66% the time-life of the graphite tubes, by avoiding the building-up of carbonaceous residues. BCR-414 plankton and ERM-CE 278 mussel tissue reference materials were used for proof-of-the-methodology. Different enzymes, protease XIV, substilisin and trypsin were studied. The use of fresh enzyme was found critical. Good Se recoveries were obtained for oyster tissue, 111%; BCR-414 plankton, 106% and ERM-CE 278 mussel tissue, 93%, when protease XIV was used. Data regarding microwave digestion versus EPS methodology is also presented and discussed.
Vale
G
G
REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Monte da Caparica, Portugal.
Pereira
S
S
Mota
A
A
Fonseca
L
L
Capelo
J L
JL
D000818:Animals; D008872:Microwaves; D010125:Ostreidae / Q000737:chemistry; D010447:Peptide Hydrolases / Q000737:chemistry*; D028222:Picea / Q000737:chemistry; D010933:Plankton / Q000737:chemistry; D012015:Reference Standards; D012643:Selenium / Q000032:analysis*; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction; D013010:Sonication; D013054:Spectrophotometry, Atomic / Q000379:methods*; D013381:Subtilisins / Q000737:chemistry; D013696:Temperature; D014357:Trypsin / Q000737:chemistry
D010447:Peptide Hydrolases; D013381:Subtilisins; D014357:Trypsin; C030732:protease IV; D012643:Selenium