Biodegradation of crude oil saturated fraction supported on clays

The role of clay minerals in crude oil saturated hydrocarbon removal during biodegradation was investigated in aqueous clay/saturated hydrocarbon microcosm experiments with a hydrocarbon degrading microorganism community. The clay minerals used for this study were montmorillonite, palygorskite, saponite and kaolinite. The clay mineral samples were treated with hydrochloric acid and didecyldimethylammonium bromide to produce acid activated- and organoclays respectively which were used in this study. The production of organoclay was restricted to only montmorillonite and saponite because of their relative high CEC. The study indicated that acid activated clays, organoclays and unmodified kaolinite, were inhibitory to biodegradation of the hydrocarbon saturates. Unmodified saponite was neutral to biodegradation of the hydrocarbon saturates. However, unmodified palygorskite and montmorillonite were stimulatory to biodegradation of the hydrocarbon saturated fraction and appears to do so as a result of the clays’ ability to provide high surface area for the accumulation of microbes and nutrients such that the nutrients were within the ‘vicinity’ of the microbes. Adsorption of the saturated hydrocarbons was not significant during biodegradation.     

Adsorption/Desorption of toluene on clay minerals

Adsorption/desorption of toluene on montmorillonite, illite, and kaolinite was studied using the batch equilibrium method. The isotherms measured fit the Freundlich equation (r² >0.95). Montmorillonite adsorbed more toluene than illite or kaolinite; the adsorption of toluene on illite and kaolinite was not significantly different. Adsorption of toluene by montmorillonite showed an exponential increase as the ratio of toluene to clay was increased from 5 to 100. The rate studies showed that 62% of the adsorption was completed within 6 h. A rapid desorption was observed initially, followed by slow desorption after 1 h. The desorption rate decreased as the time of adsorption was increased. Almost all of the adsorbed toluene was extracted with water from the clay when the adsorption time was 0.1 h, but only 61% of the toluene could be desorbed when the adsorption time was 24 h.     

Biodegradation of Dispersed Oil in Arctic Seawater at -1°C

As offshore oil and gas exploration expands in the Arctic, it is important to expand the scientific understanding of arctic ecology and environmental impact to mitigate operational risks. Understanding the fate of oil in arctic seawater is a key factor for consideration. Here we report the chemical loss due to the biodegradation of Alaska North Slope (ANS) crude oil that would occur in the water column following the successful dispersion of a surface oil slick. Primary biodegradation and mineralization were measured in mesocosms containing Arctic seawater collected from the Chukchi Sea, Alaska, incubated at −1°C. Indigenous microorganisms degraded both fresh and weathered oil, in both the presence and absence of Corexit 9500, with oil losses ranging from 46−61% and up to 11% mineralization over 60 days. When tested alone, 14% of 50 ppm Corexit 9500 was mineralized within 60 days. Our study reveals that microorganisms indigenous to Arctic seawater are capable of performing extensive biodegradation of chemically and physically dispersed oil at an environmentally relevant temperature (−1°C) without any additional nutrients.     

Specificity of virus adsorption to clay minerals

Competitive adsorption studies indicated that reovirus type 3 and coliphage T1 did not share common adsorption sites on kaolinite and montmorillonite. Compounds in the minimal essential medium (e.g., fetal bovine serum, amino acids) in which the reovirus was maintained blocked adsorption of coliphage T1 to kaolinite and partially to montmorillonite in synthetic estuarine water, but they had no effect on coliphage adsorption to montmorillonite in distilled water or on the adsorption of the reovirus to either clay. The blockage of positively charged sites on kaolinite or montmorillonite by treatment of the clays with sodium metaphosphate or with the supernatants from montmorillonite or kaolinite, respectively, had no effect on adsorption of the reovirus. These data indicate that there was a specificity in adsorption sites for mixed populations of reovirus type 3 and coliphage T1 and emphasize the importance of using more than one type of virus, especially in combination, to predict virus behavior (e.g., adsorption, loss of infectivity) in soils and sediments containing clay minerals.     

Adsorption and separation of proteins by a smectitic clay mineral

The adsorption of proteins by a smectitic clay mineral was investigated. The clay used in this study is a mixture of montmorillonite and amorphous SiO₂. Due to the high porosity the montmorillonite units are accessible for protein adsorption. The amorphous silica prevents the montmorillonite from swelling and allows column packing. Protein adsorption was performed at different pH under static conditions. Furthermore, static capacities were determined. The material reveals high adsorption capacities for proteins under static conditions (270–408 mg/g), whereby proteins are mainly adsorbed via electrostatic interactions. The Freundlich isotherm is suggested as an adsorption model. For desorption a pH shift was found to be most effective. Binding and elution of human serum albumin and ovalbumin were tested under dynamic conditions. Dynamic capacities of about 40 mg/g for ovalbumin at 764 cm/h were found. The clay mineral provides suitable properties for the application as cost-efficient, alternative separation material.     

Adsorption of coliphages T1 and T7 to clay minerals.

Coliphages T1 and T7 of Escherichia coli were absorbed by kaolinite (K) and montmorillonite (M). Maximum adsorption of T7 (96%) to M was greater than that of T1 (84%), but the adsorption of both coliphages to K was the same (99%). Positively charged sites (i.e., anion exchange sites) on the clays appeared to be primarily responsible for the adsorption of T1 to K but only partially responsible for the adsorption of T1 to M; equilibrium adsorption isotherms of T1 to K and M did not show a correlation between adsorption and the cation exchange capacity of the clays, and the reduction in adsorption caused by sodium metaphosphate (a polyanion that interacts with positively charged sites on clay) was more pronounced with K than with M. The equilibrium adsorption isotherms of T7 to K and M suggested a correlation between adsorption and the cation exchange capacity of the clays. However, studies with sodium metaphosphate indicated that T7 also adsorbed to positively charged sites on the clays, especially on K. Adsorption of the coliphages to positively charged sites was greater with K than with M, probably because the ratio of positively charged sites to negatively charged sites was greater on K than on M.     

Binding of the protoxin and toxin proteins ofBacillus thuringiensis subsp.kurstaki on clay minerals

The equilibrium adsorption and binding of the delta-endotoxin proteins, i.e., the protoxins (M_r=132 kDa) and toxins (M_r=66 kDa), fromBacillus thuringiensis subsp.kurstaki were greater on montmorillonite than on kaolinite (five-fold more protoxin and three-fold more toxin were adsorbed on montmorillonite). Approximately two- to three-fold more toxin than protoxin was adsorbed on these clay minerals. Maximum adsorption occurred within 30 min (the shortest interval measured), and adsorption was not significantly affected by temperatures between 7° and 50°C. The proteins were more easily desorbed from kaolinite than from montmorillonite; they could not be desorbed from montmorillonite with water or 0.2% Na₂CO₃, but they could be removed with Tris-SDS (sodium dodecyl sulfate) buffer. Adsorption was higher at low pH and decreased as the pH increased. Adsorption on kaolinite was also dependent on the ionic nature of the buffers. The molecular mass of the proteins was unaltered after adsorption on montmorillonite, as shown by SDS-PAGE (polyacrylamide gel electrophoresis) of the desorbed proteins; no significant modifications occurred in their structure as the result of binding on the clay, as indicated by infrared analysis; and there was no significant expansion of the clay by the proteins, as shown by x-ray diffraction analysis. The bound proteins appeared to retain their insecticidal activity against the third instar larvae ofTrichoplusia ni.     

Effect of proteins on reovirus adsorption to clay minerals

Organic matter in sewage, soil, and aquatic systems may enhance or inhibit the infectivity of viruses associated with particulates (e.g., clay minerals, sediments). The purpose of this investigation was to identify the mechanisms whereby organic matter, in the form of defined proteins, affects the adsorption of reovirus to the clay minerals kaolinite and montmorillonite and its subsequent infectivity. Chymotrypsin and ovalbumin reduced the adsorption of reovirus to kaolinite and montmorillonite homoionic to sodium. Lysozyme did not reduce the adsorption of the virus to kaolinite, but it did reduce adsorption to montmorillonite. The proteins apparently competed with the reovirus for sites on the clay. As lysozyme does not adsorb to kaolinite by cation exchange, it did not inhibit the adsorption of reovirus to this clay. The amount of reovirus desorbed from lysozyme-coated montmorillonite was approximately 38% less (compared with the input population) than that from uncoated or chymotrypsin-coated montmorillonite after six washings with sterile distilled water. Chymotrypsin and lysozyme markedly decreased reovirus infectivity in distilled water, whereas infectivity of the virus was enhanced after recovery from an ovalbumin-distilled water-reovirus suspension (i.e., from the immiscible pelleted fraction plus supernatant). The results of these studies indicate that the persistence of reovirus in terrestrial and aquatic environments may vary with the type of organic matter and clay mineral with which the virus comes in contact.     

Isolation and characterization of Halomonas sp. strain C2SS100, a hydrocarbon-degrading bacterium under hypersaline conditions

Aims:  To isolate and characterize an efficient hydrocarbon-degrading bacterium under hypersaline conditions, from a Tunisian off-shore oil field.
Methods and Results:  Production water collected from 'Sercina' petroleum reservoir, located near the Kerkennah island, Tunisia, was used for the screening of halotolerant or halophilic bacteria able to degrade crude oil. Bacterial strain C2SS100 was isolated after enrichment on crude oil, in the presence of 100 g l⁻¹ NaCl and at 37°C. This strain was aerobic, Gram-negative, rod-shaped, motile, oxidase + and catalase +. Phenotypic characters and phylogenetic analysis based on the 16S rRNA gene of the isolate C2SS100 showed that it was related to members of the Halomonas genus. The degradation of several compounds present in crude oil was confirmed by GC–MS analysis. The use of refined petroleum products such as diesel fuel and lubricating oil as sole carbon source, under the same conditions of temperature and salinity, showed that significant amounts of these heterogenic compounds could be degraded. Strain C2SS100 was able to degrade hexadecane (C₁₆). During growth on hexadecane, cells surface hydrophobicity and emulsifying activity increased indicating the production of biosurfactant by strain C2SS100.
Conclusions:  A halotolerant bacterial strain Halomonas sp. C2SS100 was isolated from production water of an oil field, after enrichment on crude oil. This strain is able to degrade hydrocarbons efficiently. The mode of hydrocarbon uptake is realized by the production of a biosurfactant which enhances the solubility of hydrocarbons and renders them more accessible for biodegradation.
Significance and Impact of the Study:  The biodegradation potential of the Halomonas sp. strain C2SS100 gives it an advantage for possibly application on bioremediation of water, hydrocarbon-contaminated sites under high-salinity level.     

Effect of proteins on reovirus adsorption to clay minerals.

Organic matter in sewage, soil, and aquatic systems may enhance or inhibit the infectivity of viruses associated with particulates (e.g., clay minerals, sediments). The purpose of this investigation was to identify the mechanisms whereby organic matter, in the form of defined proteins, affects the adsorption of reovirus to the clay minerals kaolinite and montmorillonite and its subsequent infectivity. Chymotrypsin and ovalbumin reduced the adsorption of reovirus to kaolinite and montmorillonite homoionic to sodium. Lysozyme did not reduce the adsorption of the virus to kaolinite, but it did reduce adsorption to montmorillonite. The proteins apparently competed with the reovirus for sites on the clay. As lysozyme does not adsorb to kaolinite by cation exchange, it did not inhibit the adsorption of reovirus to this clay. The amount of reovirus desorbed from lysozyme-coated montmorillonite was approximately 38% less (compared with the input population) than that from uncoated or chymotrypsin-coated montmorillonite after six washings with sterile distilled water. Chymotrypsin and lysozyme markedly decreased reovirus infectivity in distilled water, whereas infectivity of the virus was enhanced after recovery from an ovalbumin-distilled water-reovirus suspension (i.e., from the immiscible pelleted fraction plus supernatant). The results of these studies indicate that the persistence of reovirus in terrestrial and aquatic environments may vary with the type of organic matter and clay mineral with which the virus comes in contact.     

Assessment of C:N Ratios and Water Potential for Nitrogen Optimization in Diesel Bioremediation

Sandy clay loam soil contaminated with 5000, 10,000 or 20,000 mg/kg of diesel fuel no. 2 was amended with 0 (ambient nitrogen only), 250, 500, or 1000 mg/kg nitrogen (NH₄Cl) to evaluate the role of C:N ratios and soil water potential on diesel biodegradation efficacy. The soil was incubated at 25°C for 41 days and microbial O₂ consumption measured respirometrically. Highest microbial respiration was observed in the 250 mg N/kg soil treatments regardless of diesel concentration. Higher levels of nitrogen fertilization decreased soil water potential and resulted in an extended lag phase and reduced respiration. Application of 1000 mg/kg nitrogen reduced maximum respiration by 20% to 52% depending on contaminant levels. Optimal C:N ratios among those tested were 17:1, 34:1, and 68:1 for the three diesel concentrations, respectively, and were dependent on contaminant concentration. Nitrogen fertilization on the basis of soil pore water nitrogen (mg N/kg soil H₂O) is independent of hydrocarbon concentration but takes into account soil moisture content. This method accounts for both the nutritional and osmotic aspects of nitrogen fertilization. In the soil studied the best nitrogen augmentation corresponded to a soil pore water nitrogen level of 1950 mg N/kg H₂O at all diesel concentrations.     

Biodegradation study by Pseudomonas sp. of flexible polyurethane foams derived from castor oil

The synthesis and biodegradation of polyurethane foams obtained from environmentally benign processes were studied.Flexible polyurethane foams based on castor oil modified with maleic anhydride (MACO) were synthesized. The synthesis involved a single-stage process by mixing castor oil/MACO (weight ratios 75:25 and 25:75) and 2-4 toluene diisocyanate (TDI) in stoichiometric amount of OH:NCO. The biodegradability studies with cultures of a Pseudomonas sp. strain (DBFIQ-P36) involved incubation periods of 2 months at 37 °C. Polymers were characterized before and after biodegradation by Fourier Transform Infrared Spectroscopy (FT-IR), INSTRON mechanical tester, and Scanning Electron Microscopy (SEM). The results showed that the addition of MACO produces a considerable increase in the rate of degradation and an important change in the chemical and morphological structures. This is due to the presence of ester groups that are vulnerable to chemical hydrolysis and enzymatic attack. The eco-toxicity after the biodegradation was evaluated. Toxic compounds such as primary amines were identified by Gas Chromatography–Mass Spectrometry (GC–MS) in combination with Nuclear Magnetic Resonance (NMR) as degradation products.     

Adsorption of reovirus to clay minerals: effects of cation-exchange capacity, cation saturation, and surface area

The adsorption of reovirus to clay minerals has been reported by several investigators, but the mechanisms defining this association have been studied only minimally. The purpose of this investigation was to elucidate the mechanisms involved with this interaction. More reovirus type 3 was adsorbed, in both distilled and synthetic estuarine water, by low concentrations of montmorillonite than by comparable concentrations of kaolinite containing a mixed complement of cations on the exchange complex. Adsorption to the clays was essentially immediate and was correlated with the cation-exchange capacity of the clays, indicating that adsorption was primarily to negatively charged sites on the clays. Adsorption was greater with low concentrations of clays in estuarine water than in distilled water, as the higher ionic strength of the estuarine water reduced the electrokinetic potential of both clay and virus particles. The addition of cations (as chloride salts) to distilled water enhanced adsorption, with divalent cations being more effective than monovalent cations and 10(-2) M resulting in more adsorption than 10(-3) M. Potassium ions suppressed reovirus adsorption to montmorillonite, probably by collapsing the clay lattices and preventing the expression of the interlayer-derived cation-exchange capacity. More virus was adsorbed by montmorillonite made homoionic to various mono-, di-, and trivalent cations (except by montmorillonite homoionic to potassium) than by comparable concentrations of kaolinite homoionic to the same cations. The sequence of the amount of adsorption to homoionic montmorillonite was Al greater than Ca greater than Mg greater than Na greater than K; the sequence of adsorption to kaolinite was Na greater than Al greater than Ca greater than Mg greater than K. The constant partition-type adsorption isotherms obtained when the clay concentration was maintained constant and the virus concentration was varied indicated that a fixed proportion of the added virus population was adsorbed, regardless of the concentration of infectious particles. A heterogeneity within the reovirus population was indicated.     

Adsorption of reovirus to clay minerals: effects of cation-exchange capacity, cation saturation, and surface area.

The adsorption of reovirus to clay minerals has been reported by several investigators, but the mechanisms defining this association have been studied only minimally. The purpose of this investigation was to elucidate the mechanisms involved with this interaction. More reovirus type 3 was adsorbed, in both distilled and synthetic estuarine water, by low concentrations of montmorillonite than by comparable concentrations of kaolinite containing a mixed complement of cations on the exchange complex. Adsorption to the clays was essentially immediate and was correlated with the cation-exchange capacity of the clays, indicating that adsorption was primarily to negatively charged sites on the clays. Adsorption was greater with low concentrations of clays in estuarine water than in distilled water, as the higher ionic strength of the estuarine water reduced the electrokinetic potential of both clay and virus particles. The addition of cations (as chloride salts) to distilled water enhanced adsorption, with divalent cations being more effective than monovalent cations and 10(-2) M resulting in more adsorption than 10(-3) M. Potassium ions suppressed reovirus adsorption to montmorillonite, probably by collapsing the clay lattices and preventing the expression of the interlayer-derived cation-exchange capacity. More virus was adsorbed by montmorillonite made homoionic to various mono-, di-, and trivalent cations (except by montmorillonite homoionic to potassium) than by comparable concentrations of kaolinite homoionic to the same cations. The sequence of the amount of adsorption to homoionic montmorillonite was Al greater than Ca greater than Mg greater than Na greater than K; the sequence of adsorption to kaolinite was Na greater than Al greater than Ca greater than Mg greater than K. The constant partition-type adsorption isotherms obtained when the clay concentration was maintained constant and the virus concentration was varied indicated that a fixed proportion of the added virus population was adsorbed, regardless of the concentration of infectious particles. A heterogeneity within the reovirus population was indicated.     

Efficiency of Indigenous and Inoculated Cold-Adapted Soil Microorganisms for Biodegradation of Diesel Oil in Alpine Soils

Biodegradation of diesel oil (5 g(middot)kg [soil dry weight](sup-1)) was investigated in five alpine subsoils, differing in soil type and bedrock, in laboratory experiments during 20 days at 10(deg)C. The biodegradation activities of the indigenous soil microorganisms and of a psychrotrophic diesel oil-degrading inoculum and the effect of biostimulation by inorganic fertilization (C/N/P ratio = 100:10:2) were determined. Fertilization significantly enhanced diesel oil biodegradation activity of the indigenous soil microorganisms. Biostimulation by fertilization enhanced diesel oil biodegradation to a significantly greater degree than bioaugmentation with the psychrotrophic inoculum. In none of the five soils did fertilization plus inoculation result in a higher decontamination than fertilization alone. A total of 16 to 23% of the added diesel oil contamination was lost by abiotic processes. Total decontamination without and with fertilization was in the range of 16 to 31 and 27 to 53%, respectively.     

Assessment of C:N Ratios and Water Potential for Nitrogen Optimization in Diesel Bioremediation

Sandy clay loam soil contaminated with 5000, 10,000 or 20,000 mg/kg of diesel fuel no. 2 was amended with 0 (ambient nitrogen only), 250, 500, or 1000 mg/kg nitrogen (NH₄Cl) to evaluate the role of C:N ratios and soil water potential on diesel biodegradation efficacy. The soil was incubated at 25°C for 41 days and microbial O₂ consumption measured respirometrically. Highest microbial respiration was observed in the 250 mg N/kg soil treatments regardless of diesel concentration. Higher levels of nitrogen fertilization decreased soil water potential and resulted in an extended lag phase and reduced respiration. Application of 1000 mg/kg nitrogen reduced maximum respiration by 20% to 52% depending on contaminant levels. Optimal C:N ratios among those tested were 17:1, 34:1, and 68:1 for the three diesel concentrations, respectively, and were dependent on contaminant concentration. Nitrogen fertilization on the basis of soil pore water nitrogen (mg N/kg soil H₂O) is independent of hydrocarbon concentration but takes into account soil moisture content. This method accounts for both the nutritional and osmotic aspects of nitrogen fertilization. In the soil studied the best nitrogen augmentation corresponded to a soil pore water nitrogen level of 1950 mg N/kg H₂O at all diesel concentrations.     

Effect of environmental parameters on the biodegradation of oil sludge.

A laboratory study was conducted with the aim of evaluating and optimizing the environmental parameters of "landfarming", i.e., the disposal by biodegradation in soil of oily sludges generated in the refining of crude oil and related operations. Oil sludge biodegradation was monitored by CO2 evolution and by periodic analysis of residual hydrocarbons. The parameters studied were soil moisture, pH, mineral nutrients, micronutrients, organic supplements, treatment rate, teratment frequency, and incubation temperature. Oil sludge biodegradation was optimal at a soil water-holding capacity of 30 to 90%, a pH of 7.5 to 7.8, C:N and C:P ratios of 60:1 and 800:1, respectively, and a temperature of 20 degrees C or above. Addition of micronutrients and organic supplements was not beneficial; sewage sludge interfered with hydrocarbon biodegradation. Breakdown of the saturated hydrocarbon (alkane and cycloalkane) fraction was the highest at low application rates, but higher application rates favored the biodegradation of the aromatic and asphaltic fractions. An application rate of 5% (wt/wt) oil sludge hydrocarbon to the soil (100,000 liters/hectare) achieved a good compromise between high biodegradation rates and efficient land use and resulted in the best overall biodegradation rate of all hydrocarbon classes. Frequent small applications resulted in higher biodegradation than single large applications. Two 100,000-liter/hectare (255 barrels per acre) or four 50,000-liter/hectare oil sludge hydrocarbon applications per growing season seem appropriate for most temperate zone disposal sites.     

Effect of varying Mg/Ca ratio and electrolyte concentration in the irrigation water on the soil properties and growth of wheat

This paper discusses the results of a pot experiment conducted to study the effect of irrigation waters having varying Mg/Ca ratio (2, 4, 8 and 16) and electrolyte concentration (20 and 80 meq/l) on the soil properties and growth of wheat crop in two different soils. The development of salinity in the soils generally increased at higher electrolyte concentration of the irrigation water, but it was of a greater magnitude in the heavy-textured black soil dominated by montmorillonite clay mineral than in the light-textured alluvial soil having illite type of clay mineral. The accumulation of soluble salts as a result of saline water irrigation was higher in the surface layer than in the subsurface layer in both soils. The adsorption of Na and Mg in the soils increased with an increase in the Mg/Ca ratio and electrolyte concentration of the irrigation water. These changes in soil properties were adequately reflected by the grain and dry matter yields of wheat crop, which showed a significant reduction with an increase in the Mg/Ca ratio and electrolyte concentration of the irrigation water. However, the effects of these treatments were more pronounced in the heavy black clay soil than in the alluvial soil. Thus, the role of Mg is different from that of Ca under the conditions used in the experiment.     

Physical and Biological Treatment of Oil-Contaminated Soil in a Baffled Roller Bioreactor

Physical and biological removal of diesel oil from contaminated soil was studied in a baffled roller bioreactor. Initially, the effects of four factors (soil loading, temperature, pH, and surfactant) on physical removal of diesel oil were investigated. Only the presence of a surfactant (sodium dodecyl sulfate [SDS]) demonstrated a significant effect on diesel oil removal. Diesel oil removal efficiency was increased from 32.0% to 63.9% in the presence of 100 mg/L SDS. Using a microbial culture enriched from contaminated soil, biological treatment of diesel oil polluted soil under different soil loadings (15% to 50%), different diesel oil concentrations (1 to 50 g/L), and different types of soil (sand, silt, and clay) was then investigated in the baffled roller bioreactor. Biodegradation consisted of both fast and slow stages for degradation of light and heavy compounds, respectively. All biodegradation experiments demonstrated significant decreases in diesel oil concentrations (88.3% in 14 days for initial diesel oil concentrations of 1000 mg/L and a wide range of soil loadings). The presence of silty or sandy soils enhanced the biodegradation rate compared to the control bioreactor (without soil). The sandy soil loading had no effect on the biodegradation results. Using the enriched culture, the baffled roller bioreactor was able to biodegrade high diesel concentrations (up to 50 g/L) with biodegradation rates of 112.2 and 39.3 mg/L· h during fast and slow stages, respectively.     

Differentiation and quantification of C1 and C2 C-labeled glucose by tandem mass spectrometry

The fragmentation patterns of various ¹³C-labeled glucose molecules were analyzed by electrospray ionization tandem mass spectrometry. Derivatization of glucose to yield methylglucosamine makes the C-C bond between C1 and C2 a favored cleavage site. This is in contrast to underivatized glucose, which favorably undergoes loss of a fragment containing both C1 and C2. Based on the fragmentation pattern of methylglucoasmine, we developed a method to distinguish and quantify C1 and C2 ¹³C-labeled glucose by derivatization with methylamine followed by multiple reaction monitoring scans in a Q-trap mass spectrometer. Fragment ion ratios in the tandem mass spectra showed an isotope effect with ¹³C or deuterium labeling, so a “correction factor” was introduced to make the quantification more accurate. The current approach can be applied to individually monitor the metabolic origin and fate of C1 and C2 atoms in ¹³C-labeled glucose. This method provides a new means of quantifying glucose isotopomers in metabolic studies.