Optimization of a Digestion Method to Determine Total Mercury in Fish Tissue by Cold Vapor Atomic Fluorescence Spectrophotometry
Abstract
1. Introduction
2. Materials and Methods
2.1. Instrumentation
2.2. Chemical and Reagents
2.3. Methodology
2.4. Analytical Quality Assurance
3. Results and Discussion
3.1. Optimization of the Microwave-Assisted Digestion Method
3.2. Analytical Features of the Proposed Method
3.3. Applications
4. Conclusions
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
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Original Features of the References | Modifications | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Digestion Technique | Sample Amount (g) | Reagents for Digestion | Temperature (°C) | Ramp Time (min) | Holding Time (min) | Power (W) | Pressure (psi) | Recovery Obtained (%) | Reference | |
Microwave-assisted digestion | 0.25 | 4 cm3 HNO3 1 cm3 H2O2 0.1 cm3 of 50 mg·dm−3 Au + Lu solution | 190 | 20 | 10 | No power value described | No pressure value described | 54.5 | [43] | 0.3 g of sample amount was used. No addition of 0.1 cm3 of the 50 mg·dm−3 Au + Lu solution to each digestion vessel. Power set to 1440 W. Pressure not applied. MARSXpress vessels were used. |
Wet ashing, hot plate | 0.3 | 5 cm3 HNO3 4 cm3 H2O2 1 cm3 HClO4 | 200 | --- | --- | --- | --- | 55.7 | [44] | 0.3 g of sample amount was used. No addition of 45 mg of V2O5 to samples and no dilution to 50 cm3 with 20 cm3 distilled water and K2Cr2O7 (% 2). Pressure not applied. |
Microwave-assisted digestion | 0.5 g 1.0 g 2.0 g | 1.0 ± 0.01 cm3 NaCl 1% (w/v) 5.0 ± 0.1 cm3 HNO3 | 130 | 10 | --- | 300 | No pressure value described | 49.3 | [31] | 0.3 g of sample amount was used. Ramp temperature was modified from 5 to 10 min for heating from ambient to 130 °C. No dilution to 50 cm3 adding 3.5 ± 0.1 cm3 HCl. Pressure not applied. MARSXpress vessels were used. |
--- | 20 | 1200 | ||||||||
Microwave-assisted digestion | 0.5 | 5 cm3 HNO3 2 cm3 H2O2 | 110 | 5 | 3 | 1600 | No pressure value described | 60.2 | [45] | 0.3 g fish muscle was used. Power at 100% for the equipment used by the reference authors was 1600 W; we used 1800 W as per the CEM MARS 6 specifications. Pressure not applied. MARSXpress vessels were used. |
150 | 4 | 8 | 1600 | |||||||
180 | 3 | 25 | 1600 | |||||||
Microwave-assisted digestion | 0.2 | 8 cm3 HNO3 2 cm3 H2O2 | 180 | 20 | 50 | No power value described | No pressure value described | 66.7 | [46] | 0.3 g fish muscle was used. Power set at 1600 W. Pressure not applied. MARSXpress vessels were used. |
Wet ashing, hot plate | 0.5 | 3 cm3 HNO3 1 cm3 HClO4 5 cm3 H2SO4 | 230 | --- | --- | --- | --- | 90.3 | [47] | Method not modified at CESAQ-PUCE. |
Microwave-assisted digestion | 0.5 | 5 cm3 HNO3 2 cm3 H2O2 | 110 | 15 | 3 | 1600 | No pressure value described | 77.1 | [45] | 0.3 g fish muscle was used. Addition of 1 cm3 of HClO4 to each vessel. Pressure set at 800 psi. Power at 100% for the equipment used by the reference authors was 1600 W; we used 1800 W as per the CEM MARS 6 specifications. MARSEasyPrep vessels were used. |
150 | 4 | 8 | 1600 | |||||||
180 | 3 | 25 | 1600 | |||||||
Microwave-assisted digestion | 0.2 | 1 cm3 HNO3 1 cm3 H2O2 | No temperature value described | Microwave heating program for 2–3 min. | 80% of total power (900 W) | No pressure value described | 65.2 | [48] | 0.3 g fish muscle was used. Power and pressure set at 1400 W and 800 psi, respectively. Temperature set at 210 °C, ramp time: 20 min, holding time: 15 min. No dilution to 25 cm3 of volumetric flask with 0.1 M HCl. MARSEasyPrep vessels were used. |
Type of Vessel | Sample Amount (g) | Reagents for Digestion | Temperature (°C) | Ramp Time (min) | Holding Time (min) | Power (W) | Pressure (psi) | Recovery (%) |
---|---|---|---|---|---|---|---|---|
MARSXpress | 0.3 | 4 cm3 HNO3 1 cm3 H2O2 | 190 | 20 | 10 | 1440 | no pressure control used | 70.5 |
MARSXpress | 0.3 | 5 cm3 HNO3 4 cm3 H2O2 1 cm3 HClO4 | 200 | 20 | 10 | 1440 | no pressure control used | 68.3 |
MARSXpress | 0.3 | 5 cm3 HNO3 4 cm3 H2O2 1 cm3 HClO4 | 180 | 10 | 15 | 1800 | no pressure control used | 62.9 |
MARSXpress | 0.3 | 5 cm3 HNO3 4 cm3 H2O2 1 cm3 HClO4 | 180 | 25 | 15 | 1800 | no pressure control used | 64.3 |
MARSXpress | 0.3 | 5 cm3 HNO3 4 cm3 H2O2 1 cm3 HClO4 | 180 | 25 | 30 | 1800 | no pressure control used | 66.5 |
MARSXpress | 0.3 | 5 cm3 HNO3 4 cm3 H2O2 1 cm3 HClO4 | 200 | 25 | 20 | 1800 | no pressure control used | 67.9 |
MARSXpress | 0.3 | 5 cm3 HNO3 4 cm3 H2O2 1 cm3 HClO4 | 190 | 25 | 20 | 1800 | no pressure control used | 71.0 |
MARSXpress | 0.3 | 5 cm3 HNO3 4 cm3 H2O2 1 cm3 HClO4 | 200 | 25 | 25 | 1200 | no pressure control used | 65.2 |
MARSXpress | 0.3 | 5 cm3 HNO3 4 cm3 H2O2 1 cm3 HClO4 | 200 | 25 | 25 | 1400 | no pressure control used | 61.0 |
MARSXpress | 0.3 | 5 cm3 HNO3 4 cm3 H2O2 1 cm3 HClO4 | 130 | 10 | 300 | no pressure control used | 52.6 | |
20 | 600 | |||||||
MARSXpress | 0.3 | 1 cm3 HNO3 1 cm3 HClO4 5 cm3 H2SO4 | 200 | 20 | 35 | 1800 | no pressure control used | 69.3 |
MARSEasyPrep | 0.3 | 5 cm3 HNO3 4 cm3 H2O2 1 cm3 HClO4 | 200 | 15 | 15 | 1400 | 800 | 79.8 |
MARSEasyPrep | 0.3 | 5 cm3 HNO3 4 cm3 H2O2 1 cm3 HClO4 | 200 | 25 | 25 | 1400 | 800 | 73.5 |
MARSEasyPrep | 0.3 | 5 cm3 HNO3 4 cm3 H2O2 1 cm3 HClO4 | 200 | 25 | 25 | 1400 | 800 | 84.1 |
MARSEasyPrep | 0.3 | 1 cm3 HNO3 1 cm3 H2O2 1 cm3 HClO4 | 200 | 15 | 15 | 1400 | 800 | 86.9 |
MARSEasyPrep | 0.3 | 1 cm3 HNO3 1 cm3 H2O2 1 cm3 HClO4 | 220 | 20 | 15 | 1400 | 800 | 94.4 |
MARSEasyPrep | 0.3 | 1 cm3 HNO3 1 cm3 H2O2 1 cm3 HClO4 | 210 | 20 | 15 | 1400 | 800 | 95.2 |
Step | Temperature (°C) | Ramp Time (min) | Holding Time (min) | Power (watts) | Pressure (psi) |
---|---|---|---|---|---|
1 | 210 | 20 | 15 | 1400 | 800 |
Concentration Expected (mg·kg−1) | Concentration Found a (mg·kg−1) | Highest Repeatability Precision RSD a (%) | Intermediate Precision RSD a (%) | Recovery (%) |
---|---|---|---|---|
0.167 | 0.174 | 3.0 | 4.2 | 104.3 |
0.500 | 0.498 | 1.5 | 1.7 | 99.5 |
0.833 | 0.819 | 2.7 | 3.4 | 98.3 |
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Yánez-Jácome, G.S.; Romero-Estévez, D.; Navarrete, H.; Simbaña-Farinango, K.; Vélez-Terreros, P.Y. Optimization of a Digestion Method to Determine Total Mercury in Fish Tissue by Cold Vapor Atomic Fluorescence Spectrophotometry. Methods Protoc. 2020, 3, 45. https://doi.org/10.3390/mps3020045
Yánez-Jácome GS, Romero-Estévez D, Navarrete H, Simbaña-Farinango K, Vélez-Terreros PY. Optimization of a Digestion Method to Determine Total Mercury in Fish Tissue by Cold Vapor Atomic Fluorescence Spectrophotometry. Methods and Protocols. 2020; 3(2):45. https://doi.org/10.3390/mps3020045
Chicago/Turabian StyleYánez-Jácome, Gabriela S., David Romero-Estévez, Hugo Navarrete, Karina Simbaña-Farinango, and Pamela Y Vélez-Terreros. 2020. "Optimization of a Digestion Method to Determine Total Mercury in Fish Tissue by Cold Vapor Atomic Fluorescence Spectrophotometry" Methods and Protocols 3, no. 2: 45. https://doi.org/10.3390/mps3020045
APA StyleYánez-Jácome, G. S., Romero-Estévez, D., Navarrete, H., Simbaña-Farinango, K., & Vélez-Terreros, P. Y. (2020). Optimization of a Digestion Method to Determine Total Mercury in Fish Tissue by Cold Vapor Atomic Fluorescence Spectrophotometry. Methods and Protocols, 3(2), 45. https://doi.org/10.3390/mps3020045