A new method for the determination of ammonium in the vitreous humour based on capillary electrophoresis and its preliminary application in thanatochemistry
-
Rossella Gottardo
Abstract
Background
Although the post-mortem increase of ammonium in biological fluids is well known, ammonium analysis in vitreous humour has never been used in recent times for the determination of the post-mortem interval. The present work represents a new application of capillary electrophoresis with indirect UV detection in the field of forensic analysis.
Methods
The electrophoretic separation was carried out in a running buffer made of 5 mM imidazole, 5 mM 18-crown-6 ether and 6 mM d,l-α-hydroxybutyric acid (HIBA). To overcome the lack of optical absorption of ammonium, indirect UV detection was applied. The used wavelength was 214 nm.
Results
The method showed good linearity in the concentration range from 0.16 to 5.0 mM. The limit of detection, 0.039 mmol/L, was established on the basis of the linearity curve. Precision and bias studies carried out on the pure ammonium solutions and in real biological samples, revealed %RSDs well below 20%. A preliminary application to real cases where the death time was precisely known (14 bodies) was carried out plotting vitreous humour ammonium vs. post-mortem interval with a resulting good linear correlation until 100 h post-mortem.
Conclusions
After validation in real cases, the present method can become a powerful tool to unravel one of the most challenging issues of forensic investigation: determination of the time of death.
Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: None declared.
Employment or leadership: None declared.
Honorarium: None declared.
Competing interests: The funding organization(s) played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.
References
1. Hubig M, Muggenthaler H, Sinicina I, Mall G. Temperature based forensic death time estimation: the standard model in experimental test. Leg Med 2015;17:381–7.10.1016/j.legalmed.2015.05.005Search in Google Scholar PubMed
2. Saukko P, Knight B. Chapter 2: The pathophysiology of death. In: Knight’s Forensic Pathology, 3rd ed. Oxford, London: CRC Press, 2004:52–97.10.1201/b13642Search in Google Scholar
3. Salam HA, Shaat EA, Aziz MH, MoneimSheta AA, Hussein HA. Estimation of postmortem interval using thanatochemistry and postmortem changes. Alexandria J Med 2012;48:335–44.10.1016/j.ajme.2012.05.004Search in Google Scholar
4. Thierauf A, Musshoff F, Madea B. Post-mortem biochemical investigations of vitreous humor. Forensic Sci Int 2009; 192:78–82.10.1016/j.forsciint.2009.08.001Search in Google Scholar PubMed
5. Balasooriya BA, Hill CA, Williams AR. The biochemistry of vitreous humour. A comparative study of the potassium, sodium and urate concentrations in the eyes at identifical time intervals after death. Forensic Sci Int 1984;26:85–91.10.1016/0379-0738(84)90064-1Search in Google Scholar PubMed
6. Coe JI. Vitreous potassium as a measure of the postmortem interval: an historical review and critical evaluation. Forensic Sci Int 1989;42:201–13.10.1016/0379-0738(89)90087-XSearch in Google Scholar
7. Zhou B, Zhang L, Zhang G, Zhang X, Jiang X. The determination of potassium concentration in vitreous humor by low pressure ion chromatography and its application in the estimation of postmortem interval. J Chromatogr B 2007;852:278–81.10.1016/j.jchromb.2007.01.027Search in Google Scholar PubMed
8. Tagliaro F, Manetto G, Cittadini F, Marchetti D, Bortolotti F, Marigo M. Capillary zone electrophoresis of potassium in human vitreous humour: validation of a new method. J Chromatogr B 1999;733:273–9.10.1016/S0378-4347(99)00338-2Search in Google Scholar PubMed
9. Tagliaro F, Bortolotti F, Manetto G, Cittadini F, Pascali VL, Marigo M. Potassium concentration differences in the vitreous humour from the two eyes revisited by microanalysis with capillary electrophoresis. J Chromatogr A 2001;924:493–8.10.1016/S0021-9673(01)00713-0Search in Google Scholar
10. Madea B. Is there recent progress in the estimation of the postmortem interval by means of thanatochemistry? Forensic Sci Int 2005;151:139–49.10.1016/j.forsciint.2005.01.013Search in Google Scholar PubMed
11. Nikolac N, Omazic J, Simundic AM. The evidence based practice for optimal sample quality for ammonia measurement. Clin Biochem 2014;47:991–5.10.1016/j.clinbiochem.2014.05.068Search in Google Scholar PubMed
12. Scientific Working Group for Forensic Toxicology (SWGTOX). Standard practices for method validation in forensic toxicology. J Anal Toxicol 2013;37:452–74.10.1093/jat/bkt054Search in Google Scholar PubMed
13. Schuff-Werner P, Steiner M. Preanalytical ammonia generation: a race with time but not with temperature. J Clin Pathol 2015;68:757–8.10.1136/jclinpath-2015-203080Search in Google Scholar PubMed
14. Bocaz-Beneventi G, Tagliaro F, Bortolotti F, Manetto G, Havel J. Capillary zone electrophoresis and artificial neural networks for estimation of the post-mortem interval (PMI) using electrolytes measurements in human vitreous humour. Int J Legal Med 2002;116:5–11.10.1007/s004140100239Search in Google Scholar PubMed
©2019 Walter de Gruyter GmbH, Berlin/Boston
Articles in the same Issue
- Frontmatter
- Editorial
- Can Grail find the trail to early cancer detection?
- Reviews
- Aberrant glycosylation and cancer biomarker discovery: a promising and thorny journey
- Application of NMR metabolomics to search for human disease biomarkers in blood
- Mini Review
- Host-response biomarkers for the diagnosis of bacterial respiratory tract infections
- Opinion Paper
- Diabetes alert dogs: a narrative critical overview
- EFLM Paper
- Documenting metrological traceability as intended by ISO 15189:2012: A consensus statement about the practice of the implementation and auditing of this norm element
- General Clinical Chemistry and Laboratory Medicine
- Commutability of external quality assessment materials for serum sodium and potassium measurements
- Standardization of measurement procedures for serum uric acid: 8-year experience from Category 1 EQA program results in China
- Next-generation rapid serum tube technology using prothrombin activator coagulant: fast, high-quality serum from normal samples
- Cannabinoids determination in bronchoalveolar lavages of cannabis smokers with lung disease
- A new method for the determination of ammonium in the vitreous humour based on capillary electrophoresis and its preliminary application in thanatochemistry
- Reference Values and Biological Variations
- Defining reference intervals for a serum growth differentiation factor-15 (GDF-15) assay in a Caucasian population and its potential utility in diabetic kidney disease (DKD)
- Cancer Diagnostics
- Preanalytical stability of [-2]proPSA in whole blood stored at room temperature before separation of serum and plasma: implications to Phi determination
- Cardiovascular Diseases
- A de novo mutation of SMYD1 (p.F272L) is responsible for hypertrophic cardiomyopathy in a Chinese patient
- Infectious Diseases
- Analyzing the capability of PSP, PCT and sCD25 to support the diagnosis of infection in cancer patients with febrile neutropenia
- Mid-regional pro-adrenomedullin predicts poor outcome in non-selected patients admitted to an intensive care unit
- Validation of Mycobacterium tuberculosis real-time polymerase chain reaction for diagnosis of tuberculous meningitis using cerebrospinal fluid samples: a pilot study
- Letters to the Editor
- Methodological issues are important in cannabinoids determination in bronchoalveolar lavage
- Clarifying methodological issues in cannabinoids determination in bronchoalveolar lavages
- Letter to the Editor relating to Clin Chem Lab Med 2018;56(7):1090–1099
- Authors’ reply to the Letter by Infantino et al. commenting on Bonroy et al.: Anti-DFS70 in different settings, CCLM 2018;56:1090–9
- High-sensitivity cardiac troponin-I analytical imprecisions evaluated by internal quality control or imprecision profile
- Procalcitonin as guide to therapy in endovascular infections: caveat emptor!
- A new suggested approach in screening for Bence Jones protein and potential kidney damage
- Establishing assay-specific 97.5th percentile upper reference limit for serum D-2-hydroxyglutarate for the management of patients with acute myeloid leukemia
- Parallel algorithm for myeloproliferative neoplasms testing: the frequency of double mutations is found in the JAK2/MPL genes more often than the JAK2/CALR genes, but is there a clinical benefit?
- CGH array for the identification of a compound heterozygous mutation in the CYP1B1 gene in a patient with bilateral anterior segment dysgenesis
- A very rare interference with the valproate method on the Beckman DxC 800 general chemistry analyser
- Congress Abstracts
- 5th EFLM Conference on Preanalytical Phase Zagreb (HR), 22-23 March 2019
Articles in the same Issue
- Frontmatter
- Editorial
- Can Grail find the trail to early cancer detection?
- Reviews
- Aberrant glycosylation and cancer biomarker discovery: a promising and thorny journey
- Application of NMR metabolomics to search for human disease biomarkers in blood
- Mini Review
- Host-response biomarkers for the diagnosis of bacterial respiratory tract infections
- Opinion Paper
- Diabetes alert dogs: a narrative critical overview
- EFLM Paper
- Documenting metrological traceability as intended by ISO 15189:2012: A consensus statement about the practice of the implementation and auditing of this norm element
- General Clinical Chemistry and Laboratory Medicine
- Commutability of external quality assessment materials for serum sodium and potassium measurements
- Standardization of measurement procedures for serum uric acid: 8-year experience from Category 1 EQA program results in China
- Next-generation rapid serum tube technology using prothrombin activator coagulant: fast, high-quality serum from normal samples
- Cannabinoids determination in bronchoalveolar lavages of cannabis smokers with lung disease
- A new method for the determination of ammonium in the vitreous humour based on capillary electrophoresis and its preliminary application in thanatochemistry
- Reference Values and Biological Variations
- Defining reference intervals for a serum growth differentiation factor-15 (GDF-15) assay in a Caucasian population and its potential utility in diabetic kidney disease (DKD)
- Cancer Diagnostics
- Preanalytical stability of [-2]proPSA in whole blood stored at room temperature before separation of serum and plasma: implications to Phi determination
- Cardiovascular Diseases
- A de novo mutation of SMYD1 (p.F272L) is responsible for hypertrophic cardiomyopathy in a Chinese patient
- Infectious Diseases
- Analyzing the capability of PSP, PCT and sCD25 to support the diagnosis of infection in cancer patients with febrile neutropenia
- Mid-regional pro-adrenomedullin predicts poor outcome in non-selected patients admitted to an intensive care unit
- Validation of Mycobacterium tuberculosis real-time polymerase chain reaction for diagnosis of tuberculous meningitis using cerebrospinal fluid samples: a pilot study
- Letters to the Editor
- Methodological issues are important in cannabinoids determination in bronchoalveolar lavage
- Clarifying methodological issues in cannabinoids determination in bronchoalveolar lavages
- Letter to the Editor relating to Clin Chem Lab Med 2018;56(7):1090–1099
- Authors’ reply to the Letter by Infantino et al. commenting on Bonroy et al.: Anti-DFS70 in different settings, CCLM 2018;56:1090–9
- High-sensitivity cardiac troponin-I analytical imprecisions evaluated by internal quality control or imprecision profile
- Procalcitonin as guide to therapy in endovascular infections: caveat emptor!
- A new suggested approach in screening for Bence Jones protein and potential kidney damage
- Establishing assay-specific 97.5th percentile upper reference limit for serum D-2-hydroxyglutarate for the management of patients with acute myeloid leukemia
- Parallel algorithm for myeloproliferative neoplasms testing: the frequency of double mutations is found in the JAK2/MPL genes more often than the JAK2/CALR genes, but is there a clinical benefit?
- CGH array for the identification of a compound heterozygous mutation in the CYP1B1 gene in a patient with bilateral anterior segment dysgenesis
- A very rare interference with the valproate method on the Beckman DxC 800 general chemistry analyser
- Congress Abstracts
- 5th EFLM Conference on Preanalytical Phase Zagreb (HR), 22-23 March 2019
