Consciousness Energy Healing Treatment Impacted the Isotopic Abundance Ratio of 6-Mercaptopurine (6-MP)
Mahendra Kumar Trivedi1, Alice Branton1, Dahryn Trivedi1 and Snehasis Jana2
1 Trivedi Global, Inc., Henderson, USA
2 Trivedi Science Research Laboratory Pvt. Ltd., Thane (W), Maharashtra, India
Submission:February 03, 2021; Published: March 16, 2021
*Corresponding author: Snehasis Jana, Trivedi Science Research Laboratory Pvt. Ltd., Thane (W), Maharashtra, India
How to cite this article: Mahendra K T, Alice B, Dahryn T, Snehasis J. Consciousness Energy Healing Treatment Impacted the Isotopic Abundance Ratio of 6-Mercaptopurine (6-MP). Nov Appro Drug Des Dev. 2021; 5(5): 555673. DOI: 10.19080/NAPDD.2021.05.555673
Abstract
6-mercaptopurine (6-MP) is an antimetabolite antineoplastic chemotherapy drug. In this research work, the impact of the Trivedi Effect® on the structural properties and the isotopic abundance ratio of 6-MP were evaluated. The 6-MP test sample was divided into two-parts and termed as control and Biofield Energy Treated sample. The treated 6-MP only received the Trivedi Effect®-Consciousness Energy Healing Treatment remotely by a well-known Biofield Energy Healer, Mahendra Kumar Trivedi. The LC-MS spectra of both the 6-MP samples at retention time (Rt) 2.2 minutes showed the mass of the protonated molecular ion peak at m/z 173 [M+H]+. The peak area of the treated 6-MP was significantly increased by 92.07% compared to the control sample. The LC-MS based isotopic abundance ratio of PM+1+PM in the treated 6-MP was significantly increased by 34.79% compared with the control sample. Similarly, the GC-MS based isotopic abundance ratios of PM+1+PM and PM+2/PM in the treated 6-MP was significantly increased by 40.78% and 377.01% compared with the control sample. Thus, 13C, 2H, 15N, 33S, and 18O contributions from (C5H5N4S)+ to m/z 153 and 154 in the Biofield Energy Treated 6-MP were significantly increased as compared to the control 6-MP. The isotopic abundance ratio of PM+1+PM (2H/1H or 13C/12C or 15N/14N or 33S/32S) and PM+2/PM (34S/32S) in the treated 6-MP was significantly improved compared to the control sample. The significant increase in the peak area and isotopic abundance could be due to the interference of neutrino particles in the nucleus via the Trivedi Effect®. The increased isotopic abundance ratio of the treated 6-MP would improve the chemical bond strength, increase the physical and chemical stability of 6-MP in the body. The Biofield Energy Treated 6-MP would be better designing more efficacious pharmaceutical formulations that might offer increased bioavailability and therapeutic response against acute lymphocytic leukemia, Crohn’s disease, chronic myeloid leukemia, and ulcerative colitis, etc.
Keywords: 6-Mercaptopurine; Biofield Energy; The Trivedi Effect®; Consciousness Energy Healing Treatment; LC-MS; GC-MS
Introduction
6-mercaptopurine (6-MP) is an antimetabolite antineoplastic chemotherapy drug. It is most effective at killing tumour cells that are rapidly dividing by interfering with the nucleic acid synthesis by inhibiting purine metabolism [1,2]. It is used as an anticancer and an immunosuppressive agent, i.e., myeloid leukaemia, lymphocytic leukaemia, ulcerative colitis, and Crohn’s disease [2-5]. It has been approved for medical use in the U.S.A. (1953) and also listed as an essential medicine by the WHO [6]. The common side effects related to the mercaptopurine use are immune and bone marrow suppression, liver toxicity, diarrhoea, loss of appetite, mouth sores, fatigue, weakness, fever, sore throat, hair loss, red spots on the skin, darkening of the skin, yellowing of eyes or skin, bloody stools, bloody or dark urine, painful or difficult urination, genetic polymorphisms, etc. [7-9]. Mercaptopurine delivered in the form of a tablet and liquid suspension [10-12]. It is soluble in hot alcohol and dilute alkali solutions; slightly soluble in dilute sulfuric acid; insoluble in water, chloroform, acetone, and diethyl ether [12].
The physicochemical properties of the pharmaceutical compound determine the quality, stability, solubility, and bioavailability [13]. The Trivedi Effect® has been scientifically proved with the significant impact on particle size, surface area, and bioavailability of pharmaceutical and nutraceutical compounds [14-18]. The Trivedi Effect® is a well-proven phenomenon in which a healer can harness this inherently intelligent energy from the Universe and transfer it anywhere on the planet through the possible mediation of neutrinos [19]. The “Biofield” is an electromagnetic energy field which exists surrounding the living beings, which generated by the continuous movement of the charged particles (i.e., ions, cells, blood flow, etc.) in the body [20-22]. The “Biofield” based Energy Therapies reported having significant positive outcomes against various disease [23]. The National Centre of Complementary and Integrative Health has approved the Biofield Energy Therapies as a Complementary and Alternative Medicine (CAM) health care approach in addition to other therapies, medicines, and practices viz. Ayurveda, homeopathy, hypnotherapy, yoga, Reiki, healing touch, Tai Chi, Qi Gong, etc. [24,25]. In similar way, the Trivedi Effect®- Consciousness Energy Healing Treatment also has a significant effect on the metals, ceramics, polymers, organic materials, crops, microbes, biotechnology, cancer cells, bone health, etc. [26-40].
This indicated that the Trivedi Effect®-Consciousness Energy Healing Treatment could be an economical approach to improve the physicochemical properties of 6-MP. The study of stable isotope ratio and its composition helps to understand the atomic bond strength, physicochemical, and thermal properties of the compound [41,42]. Isotope ratio analysis can be performed with the help of gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) in low micromolar concentration with sufficient precision [41,43]. In this study, the structural characterization and isotopic abundance ratio analysis of PM+1+PM (2H/1H or 13C/12C or 15N/14N or 33S/32S) and PM+2/PM (33S/32S) in the Consciousness Energy Healing Treated 6-MP was evaluated compared to the control sample using LC-MS and GC-MS analytical techniques.
Materials and Methods
Chemicals and Reagents
The chemicals and reagents are purchased in India and abroad. The 6-MP powder sample was procured from Tokyo Chemical Industry Co., Ltd., Japan, but the other chemicals were procured in India.
Consciousness Energy Healing Treatment Strategies
The 6-MP powder was divided into two equal parts, i.e., the control part and the treated part. The control 6-MP powder sample did not get the Biofield Energy Treatment, but the sample has received treatment from a “sham” healer, who did not have any knowledge related to Biofield. However, the treated 6-MP was received the Trivedi Effect®-Consciousness Energy Healing Treatment remotely for 3 minutes by the well-known Biofield Energy Healer, Mahendra Kumar Trivedi, USA. The Energy Treatment was provided through the Mahendra Kumar Trivedi’s unique energy transmission process. After the treatment, both the 6-MP samples were kept in the sealed conditions and characterized using LC-MS and GC-MS analytical techniques.
Characterization
Liquid Chromatography-Mass Spectrometry (LC-MS) and Calculation of Isotopic Abundance Ratio Analysis:
The LC-MS of the 6-MP was performed in LC-MS ThermoFisher Scientific (USA), equipped with a triple-stage quadrupole mass spectrometer. A reversed phase Thermo Scientific Synchronis C18 (Length-250 mm X ID 4.6 mm X 5 micron) column was used. For the sample preparation, water and acetonitrile was used as diluent. 10 μL of the 6-MP solution was injected, and the analyte was eluted in gradient mode using 0.1% formic acid in water (mobile phase A; 10%), and acetonitrile (mobile phase B; 95%) pumped at a constant flow rate of 0.5 mL/min. The chromatographic peaks were monitored at 300 nm using the PDA detector, and the mass spectrometric analysis was performed in +ve ESI mode.
The natural abundance of each isotope (C, O, H, N, and S) was predicted by comparing the intensity of the isotope peak with the base peak. The values of the natural isotopic abundance of the elements are obtained from the literature [42,43-46]. The % change in the isotopic abundance ratio (PM+1+PM) was calculated with the help of equation 1.
Where IAR: isotopic abundance ratio in the control and treated sample.
Gas Chromatography-Mass Spectrometry (GC-MS) Analysis
The GC-MS of the 6-MP was analyzed using Perkin Elmer GC equipped with a PE-5MS (30M x 250 micros x 0.250 microns) capillary column and coupled to a single quadrupole mass detector. It was operated with electron impact (EI) ionization method in positive ion mode. The % change in isotopic abundance ratios (PM+1+PM and PM+2/PM) was calculated using equation 1.
Results and Discussion
Liquid Chromatography-Mass Spectrometry (LC-MS)
A single chromatographic peak was observed in both the control and treated 6-MP chromatograms at the retention time (Rt) of 2.2 minutes (Figure 1). In the Biofield Energy Treated 6-MP, the peak area (28285376.87) was significantly increased by 92.07% as compared to the control 6-MP (14726473.48). This indicated that the solubility of the treated 6-MP was significantly improved compared with the control sample. The data were strongly supported by the recently published article in which the Consciousness Energy Healing Treatment significantly decreased the particle size and increased the surface area of 6-MP [14]. This may improve the solubility, bioavailability, and therapeutic efficacy of the treated 6-MP compared to the control sample.
As per the literature 6-MP generally shows the protonated molecular mass [M+H]+ peak at m/z 153 in positive ion mode [47]. The mass spectra of 6-MP (Figure 2) exhibited the protonated molecular ion peak at m/z 173 [M+H]+ (calculated for C5H5N4S+, 153.18) along with the fragmentation peak C5H3N4 + (m/z 119) and C4H7N2 + (m/z 82) in case of both the samples (Figure 3).
The 6-MP showed the molecular ion [M+H]+ peak at m/z 173 (calculated for C5H5N4S+, 153.18) with relative intensity of 100%. The theoretical calculation of PM+1 for 6-MP was presented as below:
P (13C) = [(5 x 1.1%) x 100% (the actual size of the M+ peak)] / 100% = 5.5%
P (2H) = [(5 x 0.015%) x 100%] / 100%= 0.075%
P (15N) = [(4 x 0.4%) x 100%] / 100% = 1.6%
P (33S) = [(1 x 0.08%) x 100%] / 100% = 0.08%
PM+1, i.e. 13C, 2H, 15N, and 33S contributions from (C5H5N4S)+ to m/z 154= 7.26%
The calculated isotope abundance was close to the experimental value (Table 1). It has been found that 13C and 15N have major contribution to m/z 154.
The LC-MS based isotopic abundance ratio analysis PM and PM+1 of the 6-MP at were obtained from the observed relative peak intensities of [M+] and [(M+1)+], respectively in the ESI-MS spectra (Table 1) of both the samples. The isotopic abundance ratio PM+1+PM in the treated 6-MP was significantly increased by 34.79% compared with the control sample (Table 1). Thus, it was concluded that the 13C, 2H, 15N, and 33S contributions from (C5H5N4S)+ to m/z 154 in the treated 6-MP were significantly decreased as compared to the control 6-MP.
Gas Chromatography-Mass Spectrometry (GC-MS) Analysis
A single chromatographic peak at the retention time of 17.46 and 16.17 minutes in the chromatogram control and treated 6-MP (Figures 4 and 5). The parent molecular ion peak of 6-MP at m/z 152 [M]+ (calculated for C5H5N4S+, 152.02) was observed in both the samples, along with the fragment ion peaks (Figures 3-5).
The theoretical calculation of PM+1 for 6-MP was done with respect to the peak intensity of the molecular ion peak [M]+ at m/z 152.
P (13C) = [(5 x 1.1%) x 77% (the actual size of the M+ peak)] / 100% = 4.24%
P (2H) = [(4 x 0.015%) x 77%] / 100%= 0.05%
P (15N) = [(4 x 0.4%) x 77%] / 100% = 1.23%
P (33S) = [(1 x 0.08%) x 77%] / 100% = 0.06%
PM+1, i.e. 13C, 2H, 15N, and 33S contributions from (C5H5N4S)+ to m/z 153 = 5.58%
Based on the above calculation, it has been observed that 13C and 15N have major contribution to m/z 153. The calculated isotopic abundances (5.58) was close to the experimental value 4.79 (Table 2).
Similarly, the theoretical calculation of PM+2 for 6-MP was presented as below:
P (34S) = [(1 x 4.21%) x 77%] / 100% = 3.24%
PM+2, i.e. 34S contributions from (C5H5N4S)+ to m/z 154 = 4.21%
From the above calculation, it has been found that only 34S have the major contribution to m/z 173.
The GC-MS based isotopic abundance PM, PM+1, and PM+2 for the mercaptopurine were obtained from the observed relative peak intensities of [M+], [(M+1)+], and [(M+2)+], respectively (Table 2). The isotopic abundance ratio of PM+1+PM in the Biofield Energy Treated 6-MP was significantly increased by 40.78% compared with the control sample (Table 2). Similarly, the isotopic abundance ratio of PM+2/PM in the treated 6-MP was significantly increased by 377.01% compared with the control sample (Table 2). Thus, 34S contributions from (C5H5N4S)+ to m/z 154 in the treated 6-MP was significantly increased compared with the control sample.
The structure of the 6-MP was confirmed from the spectral characterization. The isotopic abundance ratios of PM+1+PM (2H/1H or 13C/12C or 15N/14N or 33S/32S) and PM+2/PM (34S/32S) in the treated 6-MP were significantly improved compared to the control sample. The changes in isotopic abundance could be due to possibly the changes in nuclei, the interference of neutrino particles via the Trivedi Effect®. The neutrinos have the ability to interact with both protons and neutrons in the nucleus, which indicated a close relation between neutrino and the isotope formation [19,42,43]. The increased isotopic abundance ratios would influence the atomic bond vibration of treated 6-MP. The increased isotopic abundance ratio of the Biofield Treated 6-MP may increase the intra-atomic bond strength, its physical stability, and alter the rate reactions in the body [48]. The Consciousness Energy Healing Treated 6-MP would be very useful to design better pharmaceutical formulations that might offer better therapeutic response against chronic myeloid leukemia, acute lymphocytic leukemia, ulcerative colitis, and Crohn’s disease, etc.
Conclusion
Based on the outcomes, it was observed that the LC-MS spectra of both the 6-MP samples at Rt 2.2 minutes showed the mass of the protonated molecular ion peak at m/z 173 [M+H]+. The peak area of the Biofield Treated 6-MP was significantly increased by 92.07% as compared to the control 6-MP. The LC-MS based isotopic abundance ratio of PM+1+PM in the Biofield Treated 6-MP was significantly increased by 34.79% as compared with the control 6-MP. Similarly, the GC-MS based isotopic abundance ratios of PM+1+PM and PM+2/PM in the Biofield Energy Treated 6-MP was significantly increased by 40.78% and 377.01% compared with the control sample. Thus, 13C, 2H, 15N, 33S, and 18O contributions from (C5H5N4S)+ to m/z 153 and 154 in the Biofield Energy Treated sample were significantly increased compared with the control 6-MP. The isotopic abundance ratio of PM+1+PM (2H/1H or 13C/12C or 15N/14N or 33S/32S) and PM+2/PM (34S/32S) in the Biofield Energy Treated 6-MP was significantly improved compared to the control 6-MP. The significant increase in the peak area and isotopic abundance could be due to the interference of neutrino particles in the nucleus via the Trivedi Effect®-Consciousness Energy Treatment. The increased isotopic abundance ratio of the Biofield Energy Treated 6-MP would improve the chemical bond strength, increase the physical and chemical stability of 6-MP in the body. The Biofield Energy Treated 6-MP would be better designing more efficacious pharmaceutical formulations that might offer increased bioavailability and therapeutic response against acute lymphocytic leukemia, Crohn’s disease, chronic myeloid leukemia, and ulcerative colitis, etc.
Acknowledgements
The authors are grateful to Sophisticated Instrumentation Centre for Applied Research & Testing (SICART) India, Trivedi Science, Trivedi Global, Inc., Trivedi Testimonials, and Trivedi Master Wellness for their assistance and support during this work.
References
- Salser JS, Balis ME (1965) The mechanism of action of 6-mercaptopurine: I. Biochemical effects. Cancer Res 25(4): 539-543.
- Sahasranaman S, Howard D, Roy S (2008) Clinical pharmacology and pharmacogenetics of thiopurines. Eur J Clin Pharmacol 64(8): 753-767.
- Present DH, Korelitz BI, Wisch N, Glass JL, Sachar DB, et al. (1980) Treatment of Crohn’s disease with 6-mercaptopurine: A long-term, randomized, double-blind study. N Engl J Med 302(18): 981-798.
- Schmiegelow K, Glomstein A, Kristinsson J, Björk O (1997) Impact of morning versus evening schedule for oral methotrexate and 6-mercaptopurine on relapse risk for children with acute lymphoblastic leukemia. Nordic Society for Pediatric Hematology and Oncology (NOPHO). J Pediatr Hematol Oncol 19(2): 102-9.
- Sack DM, Peppercorn MA (1983) Drug therapy of inflammatory bowel disease. Pharmacotherapy 3(3): 158-176.
- WHO Model List of Essential Medicines, 19th List, World Health Organization. April 2015. Retrieved 10 August 2019.
- https://en.wikipedia.org/wiki/Mercaptopurine. Retrieved 10 August 2019.
- Yang JJ, Landier W, Yang W, Liu C, Hageman L, et al. (2015) Inherited NUDT15 variant is a genetic determinant of mercaptopurine intolerance in children with acute lymphoblastic leukemia. J Clin Oncol 33(11): 1235-1242.
- Moriyama T, Nishii R, Perez-Andreu V, Yang W, Klussmann FA, et al. (2016) NUDT15 polymorphisms alter thiopurine metabolism and hematopoietic toxicity. Nature Genet 48(4): 367-373.
- Lerner EI, Flashner-Barak M, Achthoven EV, Keegstra H, Smit R (2012) Formulations of 6-mercaptopurine. US patent US8188067 B2.
- Tiphaine Ade B, Hjalgrim LL, Nersting J, Breitkreutz J, Nelken B, et al. (2016) Evaluation of a pediatric liquid formulation to improve 6-mercaptopurine therapy in children. Eur J Pharm Sci 83: 1-7.
- https://pubchem.ncbi.nlm.nih.gov/compound/6-Mercaptopurine.
- Chereson R (2009) Bioavailability, bioequivalence, and drug selection. In: Makoid CM, Vuchetich PJ, Banakar UV (Eds) Basic pharmacokinetics (1st) Pharmaceutical Press, London.
- Nayak G, Trivedi MK, Branton A, Trivedi D, Jana S (2019) Impact of consciousness energy healing treatment on the physicochemical and thermal properties of an anticancer drug 6-mercaptopurine. J Cancer Oncol 3(1): 000137.
- Branton A, Jana S (2017) The use of novel and unique biofield energy healing treatment for the improvement of poorly bioavailable compound, berberine in male Sprague Dawley rats. American Journal of Clinical and Experimental Medicine 5: 138-144.
- Branton A, Trivedi MK, Trivedi D, Nayak G (2018) Evaluation of the physicochemical and thermal properties of the biofield energy healing treated ofloxacin. J Pharm Pharmaceutics 5: 80-87.
- Nayak G, Trivedi MK, Branton A, Trivedi D, Jana S (2018) Physicochemical and thermal properties of consciousness energy healing treated hydroxypropyl β-cyclodextrin. Med & Analy Chem Int J 2(3): 000124.
- Branton A, Jana S (2017) The influence of energy of consciousness healing treatment on low bioavailable resveratrol in male Sprague Dawley rats. International Journal of Clinical and Developmental Anatomy 3(3): 9-15.
- Trivedi MK, Mohan TRR (2016) Biofield energy signals, energy transmission and neutrinos. American Journal of Modern Physics 5: 172-176.
- Rubik B (2002) The biofield hypothesis: Its biophysical basis and role in medicine. J Altern Complement Med 8(6): 703-717.
- Nemeth L (2008) Energy and biofield therapies in practice. Beginnings 28(3): 4-5.
- Rivera-Ruiz M, Cajavilca C, Varon J (2008) Einthoven's string galvanometer: The first electrocardiograph. Tex Heart Inst J 35(2): 174-178.
- Rubik B, Muehsam D, Hammerschlag R, Jain S (2015) Biofield science and healing: history, terminology, and concepts. Glob Adv Health Med 4: 8-14
- Koithan M (2009) Introducing complementary and alternative therapies. J Nurse Pract 5(1): 18-20.
- Barnes PM, Bloom B, Nahin RL (2008) Complementary and alternative medicine use among adults and children: United States, 2007. Natl Health Stat Report 12: 1-23.
- Trivedi MK, Tallapragada RM (2008) A transcendental to changing metal powder characteristics. Met Powder Rep 63(9): 22-28, 31.
- Trivedi MK, Patil S, Tallapragada RM Effect of biofield treatment on the physical and thermal characteristics of Silicon, Tin and Lead powders. J Material Sci Eng 2: 125.
- Nayak G, Trivedi MK, Branton A, Trivedi D, Jana S (2018) Evaluation of the physicochemical and thermal properties of chromium trioxide (CrO3): Impact of consciousness energy healing treatment. Research & Development in Material Science 8: 1-6.
- Nayak G, Trivedi MK, Branton A, Trivedi D, Jana S (2018) Evaluation of the physicochemical and thermal properties of consciousness energy healing treated polylactic-co-glycolic acid (PLGA). Journal of Food Science and Technology 5: 117-125.
- Trivedi MK, Branton A, Trivedi D, Nayak G, Panda P, et al. (2016) Evaluation of the isotopic abundance ratio in biofield energy treated resorcinol using gas chromatography-mass spectrometry technique. Pharm Anal Acta 7: 481.
- Trivedi MK, Branton A, Trivedi D, Nayak G, Panda P, et al. (2016) Gas chromatography-mass spectrometric analysis of isotopic abundance of 13C, 2H, and 18O in biofield energy treated p-tertiary butylphenol (PTBP). American Journal of Chemical Engineering 4: 78-86.
- Trivedi MK, Branton A, Trivedi D, Nayak G, Bairwa K, et al. (2015) Physical, thermal, and spectroscopic characterization of biofield energy treated murashige and skoog plant cell culture media. Cell Biology 3: 50-57.
- Nayak G, Altekar N (2015) Effect of a biofield treatment on plant growth and adaptation. J Environ Health Sci 1: 1-9.
- Trivedi MK, Branton A, Trivedi D, Shettigar H, Nayak G, et al. (2015) Antibiogram, biochemical reactions and genotyping characterization of biofield treated Staphylococcus aureus. American Journal of Bio Science 3: 212-220.
- Trivedi MK, Branton A, Trivedi D, Nayak G, Shettigar H, et al. (2015) Antibiogram of multidrug-resistant isolates of Pseudomonas aeruginosa after biofield treatment. J Infect Dis Ther 3: 244.
- Trivedi MK, Branton A, Trivedi D, Nayak G, Mondal SC, et al. (2015) Morphological characterization, quality, yield and DNA fingerprinting of biofield energy treated alphonso mango (Mangifera indica L.) Journal of Food and Nutrition Sciences 3: 245-250.
- Trivedi MK, Branton A, Trivedi D, Nayak G, Bairwa K, et al. (2015) Physical, thermal, and spectroscopic characterization of biofield energy treated murashige and skoog plant cell culture media. Cell Biology 3: 50-57.
- Koster DA, Trivedi MK, Branton A, Trivedi D, Nayak G, et al. (2018) Evaluation of biofield energy treated vitamin D3 on bone health parameters in human bone osteosarcoma cells (MG-63). Biochemistry and Molecular Biology 3: 6-14.
- Trivedi MK, Patil S, Shettigar H, Mondal SC, Jana S (2015) The potential impact of biofield treatment on human brain tumor cells: A time-lapse video microscopy. J Integr Oncol 4: 141.
- Trivedi MK, Patil S, Shettigar H, Gangwar M, Jana S (2015) In vitro evaluation of biofield treatment on cancer biomarkers involved in endometrial and prostate cancer cell lines. J Cancer SciTher 7: 253-257.
- Schellekens RC, Stellaard F, Woerdenbag HJ, Frijlink HW, Kosterink JG (2011) Applications of stable isotopes in clinical pharmacology. Br J Clin Pharmacol 72(6): 879-897.
- Weisel CP, Park S, Pyo H, Mohan K, Witz G (2003) Use of stable isotopically labeled benzene to evaluate environmental exposures. J Expo Anal Environ Epidemiol 13(5): 393-402.
- Muccio Z, Jackson GP (2009) Isotope ratio mass spectrometry. Analyst 134(2): 213-222.
- Rosman KJR, Taylor PDP (1998) Isotopic compositions of the elements 1997 (Technical Report). Pure Appl Chem 70: 217-235.
- Smith RM (2004) Understanding Mass Spectra: A Basic Approach, Second Edition, John Wiley & Sons, Inc.
- Jürgen H (2004) Gross Mass Spectrometry: A Textbook (2nd) Springer: Berlin.
- Supandi S, Harahap Y, Harmita H, Andalusia R (2018) Quantification of 6-mercaptopurine and its metabolites in patients with acute lympoblastic leukemia using dried blood spots and UPLC-MS/MS. Sci Pharm 86(2): 18.
- Santesteban LG, Miranda C, Barbarin I, Royo JB (2014) Application of the measurement of the natural abundance of stable isotopes in viticulture: A review. Australian Journal of Grape and Wine Research 21(2): 157-167.