Influence Of Citrate Research Articles

Influence of citrate- and phosphate-based calcium sequestering salts on the disruption of casein micelles

The disruption of casein micelles through the addition of calcium sequestering salts (CSS) disodium phosphate (DSP), disodium pyrophosphate (DSPP) and tetrasodium pyrophosphate (TSPP), sodium tripolyphosphate (STPP), sodium hexametaphosphate (SHMP) and trisodium citrate (TSC) at 10, 15, 20 and 30 mEq/L levels was investigated in 5% micellar casein isolate (MCI) solution. All the CSS, except DSPP and TSPP, showed a decrease in particle size and viscosity with increasing concentration. The addition of 10–30 mEq/L of CSS to MCI decreased the protein-bound sedimentable Ca and P at pH 6.5 10 kDa-permeable Ca decreased with increasing concentration of DSP, DSPP, TSPP, STPP and SHMP. These results indicate that orthophosphates, pyrophosphates and polyphosphates combined with Ca to form insoluble Ca phosphate complexes together with casein. Higher amount of 10 kDa permeable Ca for MCI samples with TSC confirms the formation of soluble Ca-citrate complexes.

Influence of Citrate and Phosphate on the Adsorption of Adenosine-5′-Monophosphate at the Hematite Water Interface

Nucleic acid derived organic phosphorus (Po) is an important source of plant available P when degraded to inorganic phosphate (P(V)i). It is known that when nucleic acids or components are adsorbed on mineral surfaces, the enzymatic degradation is hindered or delayed. Thus, understanding adsorption/desorption mechanisms of nucleic acids and their derivatives are key to assess the biogeochemical pathways of Po cycling. Here we report adsorption mechanisms of adenosine-5′-monophosphate (AMP) on hematite, a common iron oxide mineral, under various solution properties using macroscopic and in situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopic probes. The effects of citrate, mimicking organic acids from roots exudates, and the influence of P(V)i, representing inorganic fertilizer application, were also evaluated on the release of adsorbed AMP under various solution properties. The results suggested that AMP adsorbed with the hematite surface via the phosphate moiety, N7 atom and the π electron systems of the adenine moiety. The presence of citrate significantly decreased the AMP adsorption, which was also corroborated by the negative phosphate IR bands in the results of AMP and citrate competitive adsorption experiments monitored by in situ ATR-FTIR probe. Like citrate, P(V)i also reduced AMP adsorption on hematite. Our findings suggest a potential novel pathway of nucleic acid derived Po cycling in the soil environment.

Influence of citrate and PEG coatings on the bioaccumulation of TiO2 and CeO2 nanoparticles following dietary exposure in rainbow trout

BackgroundThis study was conducted to provide much needed information on the potential of low solubility, highly biodurable nanoparticles (NPs) (TiO2 and CeO2 NPs), to bioaccumulate in fish and to investigate the relationship between an engineered nanomaterials surface coating, uptake and biokinetics in vivo. Rainbow trout (Oncorhynchus mykiss) were fed diets spiked with uncoated or surface coated (polyethylene glycol (PEG) or citrate (CIT)) TiO2 and CeO2 NPs (100 mg NPs/kg feed) for 10 days and thereafter fish were allowed to depurate for 42 days. Special care was taken to measure the real dispersed and actual administered concentrations, taking into consideration any potential losses from leaching, and to characterise the form (size, aggregation state, charge) of the NPs to which the fish were exposed.ResultsThe coatings had an influence on levels of uptake and distributions. Most notably a higher uptake of PEG and CIT coated TiO2 and CeO2 NPs compared to fish exposed to uncoated materials was observed. The elimination of any Ti from tissues was rapid during the first day of depuration, whereas Ce levels remained in fish tissues (stomach, intestine and liver) with differences in depuration and redistribution of the three types of CeO2 NPs. However, no bioaccumulation potential for both tested metal oxide NPs in fish irrespective of coatings is expected according to BMF values < 1.ConclusionsDistinct uptake, distribution and depuration kinetics in rainbow trout have been evidenced for different metal oxide NPs (TiO2 and CeO2 NPs). Coatings influenced uptake and in some cases led to slower depuration and distinct distributions, but do not make the uncoated NPs studied bioaccumulative (BMF > 1).Graphical

Вплив цитрату цинку на антиоксидантний захист у печінці та підшлунковій залозі щурів за експериментального діабету

Вплив цитрату цинку на антиоксидантний захист у печінці та підшлунковій залозі щурів за експериментального діабету

Influence of Citrate on Metal Dissolution and Respiration Rate of Microbial Leaching Cultures

The application of acidophilic iron oxidizing bacteria is an established technique in tank and heap leaching of mainly sulfidic minerals. Even though bioleaching is broadly studied, there are still several issues to solve. Especially, the formation of iron precipitates, leading to co-precipitation of valuable metals, as well as the inhibition due to coating, considerably decrease the leaching efficiency. Consequently, the addition of chelating agents should result in an increased dissolution rate.However, organic acids, which have chelating characteristics, are generally regarded as highly toxic for leaching bacteria. Nonetheless, we found that both the addition of sodium citrate and citric acid leads to an increased iron oxidation rate of 42% and 84%, respectively, compared to standard culture medium without citrate. Chemical leaching tests with ZnS and ferric iron showed similar concentrations of dissolved zinc with and without citrate. However, the actual leaching efficiency is yet to be evaluated.

The influence of citrate and oxalate on 99TcVII, Cs, NpV and UVI sorption to a Savannah River Site soil

Batch sorption experiments were conducted with 0.5–50 ppb 99Tc, 133Cs, 237Np and U in the presence and absence of citrate and/or oxalate in a 25 g/L Savannah River Site (SRS) soil suspension. Citrate and oxalate were the ligands of choice due to their relevancy to plant exudates, the nuclides were selected for their wide range of biogeochemical behavior, and the soil from SRS was selected as a model Department of Energy (DOE) site soil. Batch samples were continually mixed on a rotary shaker and maintained at a pH of approximately 5. Analysis via ICP-MS indicated that sorption of 237Np increased with ligand concentration compared to baseline studies, as did sorption of 99Tc although to a lesser extent. The increased sorption of 237Np is proposed to be due to a combination of factors that are dependent on the ligand(s) present in the specific system including, ligand dissolution of the soil by citrate and formation of tertiary soil-oxalate-Np complexes. The increased 99Tc sorption is attributed to the dissolution of the soil by the ligands, leading to an increase in the number of available sorption sites for 99Tc. Uranium sorption decreased and dissolution of native uranium was also observed with increasing ligand concentration, thought to be a result of the formation of strong U-ligand complexes remaining in the aqueous phase. The majority of these effects were observed at the highest ligand concentrations of 50 mgC/L. No notable changes were observed for the 133Cs system which is ascribed to the minimal interaction of Cs+ with these organic ligands.

Geochemical and microbial controls of the effect of citrate on phosphorus availability in a ferralsol

The secretion of organic anions, particularly citrate, by plant roots may be an effective process to mobilize phosphate (PO4) from solid constituents. However, microbial growth and corresponding phosphorus (P) immobilization can act adversely. This experimental study was aimed at studying the relative influence of geochemistry and microbiology on the influence of citrate on P availability in a tropical soil. We carried out water extractions with different citrate concentrations (0–500μM). A first set of experiment was performed at low temperature (T=2°C) in order to have only geochemical effects. We performed two other set of experiments at room temperature (T=25°C), without and with addition of glucose and nitrate, in order to investigate the influence of an increase of microbial activity. We measured an overall increase of P availability with citrate concentration in all the treatments. Results obtained at low temperature were consistent with the lack of significant P immobilization by microbial activity. The concomitant increase of dissolved Si, Al and Fe suggested that citrate enhanced the dissolution of PO4-adsorbing minerals. This geochemical process should release PO4 and increase P availability. The overall increase of P availability with temperature further suggested that the dissolution of Al- and Fe-PO4 minerals was also responsible of the effect of citrate. Lastly, results obtained at 25°C without addition of glucose and nitrate exhibited a weak effect of microbial activity, as a decrease of P availability was only observed at the lowest citrate concentration (2μM). The addition of glucose and nitrate enhanced microbial activity as a net immobilization of PO4 was observed up to 20μM of citrate. Beyond this threshold, microbial growth appeared limited by other factors as time. Our study revealed that the effect of citrate on P availability was mainly controlled by complex geochemical interactions in a range of temperature conditions. The adverse influence of microbial growth increased with temperature and nutrient supply but revealed limited. The nature and intensity of controlling geochemical processes depend on soil type and fertilization.

Citrate-enhanced release of arsenic during pyrite oxidation at circumneutral conditions

The release of arsenic (As) from the oxidation of As-rich pyrite is an important source of the high arsenic in groundwater. As a widespread low-molecular-weight organic acid, citrate plays an important role on the cycling of Fe(II)/Fe(III) through complexation in circumneutral subsurface environments, while the influence of citrate on the release of As from the oxidation of As-rich pyrite is poorly understood. In this study, As was loaded onto pyrite particles under anoxic conditions, and its release was investigated in the presence of 0–1 mM citrate at pH 7.4 under oxic conditions. As-loaded pyrite suspension was prepared by the equilibrium of 2.67 μM As(III) in 10 g/L pyrite under anoxic conditions with the decrease in dissolved As(III) concentration to 1 μM. The suspension was subsequently exposed to air for oxygenation. In the absence of citrate, the oxygenation decreased the partitioning of As in the solution because of the re-adsorption of aqueous As by the in situ generated Fe(III) oxyhydroxides. However, with the increase in citrate concentration from 0.1 to 1 mM, the As partitioned in the solution increased from 0.3 to 2.67 μM. In the presence of 1 mM citrate, the As(III) was almost completely oxidized to As(V) during the oxygenation. The mechanisms of citrate-enhanced release of As were mainly attributed to the ligand exchange of citrate with As for pyrite surface sites, the competitive adsorption of citrate with As on Fe(III) oxyhydroxides and pyrite, and the partitioning of As on the newly formed Fe(III) colloids. This finding presents an overlooked mechanism of the release of pyrite-associated As under oxic and circumneutral conditions.

The influence of Citrate or PEG coating on silver nanoparticle toxicity to a human keratinocyte cell line.

Surface coating of silver nanoparticles may influence their toxicity, in a way yet to decipher. In this study, human keratinocytes (HaCaT cells) were exposed for 24 and 48h to well-characterized 30nm AgNPs coated either with citrate (Cit30 AgNPs) or with poly(ethylene glycol) (PEG30 AgNPs), and assessed for cell viability, reactive oxygen species (ROS), cytokine release, apoptosis and cell cycle dynamics. The results showed that Cit30 AgNPs and PEG30 AgNPs decreased cell proliferation and viability, the former being more cytotoxic. The coating molecules per se were not cytotoxic. Moreover, Ag(+) release and ROS production were similar for both AgNP types. Cit30 AgNPs clearly induced apoptotic death, while cells exposed to PEG30 AgNPs appeared to be at an earlier phase of apoptosis, supported by changes in BAX, BCL2 and CASP-3 expressions. Concerning the impact on cell cycle dynamics, both Cit30 and PEG30 AgNPs affected cell cycle regulation of HaCaT cells, but, again, citrate-coating induced more drastic effects, showing earlier downregulation of cyclin B1 gene and cellular arrest at the G2 phase. Overall, this study has shown that the surface coating of AgNPs influences their toxicity by differently regulating cell-cycle and cell death mechanisms.

The effect of citrate and sulfate of copper on the biomass composition of the medicinal mushroom Trametes versicolor (Polyporales, Polyporaceae)

The aim of our research was to study the influence of citrate and sulfate of copper on the biomass composition of the mycelium of the medicinal mushroom Trametes versicolor (L.) Lloyd, (1920) cultivated in a liquid medium. The studied strain of Trametes versicolor 353 was obtained from the Culture Collection of Mushrooms (IBK) from M.G. Kholodny Institute of Botany, National Academy of Sciences of Ukraine. Copper citrate was obtained from the Institute of Nanobiotechnologies and Resource Conservation of Ukraine, Kyiv. In this study we used glucose-peptone-yeast extract medium. Cu2+ (sulfate or citrate form) was added to the medium in concentration 4 mg/L. Mycelium was grown in a submerged culture on a rotary shaker (120 rpm) at 26 °C in 250 ml Erlenmeyer flasks, containing 50 ml of liquid media. The biomass was harvested after 9 days of cultivation in the liquid medium, filtered, washed, dried to a constant weight at 105 °C and weighed. Total nitrogen content (Ntotal) in the mycelium determined by the Kjeldahl method, crude protein content was determined as Ntotal x 6.25. The ash was obtained by the standard method. Total lipids were extracted from undried mycelium by a modified method of Bligh and Dyer. Amino acid composition was analyzed by high-performance liquid chromatography Agilent 1200 (Agilent technologies, USA). The methyl ethers of fatty acids were determined by gas chromatography-mass spectrometry (GC/MS) Agilent 6890N/5973 inert. The results of our research demonstrated that sulfates and citrates of copper increased the amount of crude protein on the mycelium of T. versicolor 353. Also both form of copper increased the amount of ash by a third relative to the control medium. At the same time, both forms of copper reduced the amount of total carbohydrates on mycelial biomass. But copper sulfate reduced the amount of total lipids relative to the control medium and medium with copper citrate. It should be noted, that given the significant growth of biomass in both cases, the yield of the same biomass compounds (gram per liter of medium) was raised relative to the control medium. So the yield of total carbohydrates was increased by 72% (on the medium with copper citrate) and 43% (on the medium with copper sulfate) relative to the control medium. The yield of crude protein was raised by 94% (on the medium with copper citrate) and 63% (on the medium with copper sulfate) relative to the control medium. Assay of amino acid composition showed that the quality of crude protein didn’t change. Thus the yield of essential amino acids was increased in conjunction with the yield of crude protein. The yield of total lipids increased only on the medium with copper citrate (by 57%) and in this case the content of fatty acids was unchanged significantly relative to the control medium. But sulfate of copper decreased the amount of cis-linoleic acids by 7%, in return the amount of oleic acid was increased relative to the control medium without copper.

The effect of citrate and sulfate of different metals on carbohydrates composition of medicinal mushroom Trametes versicolor (Polyporales, Polyporaceae)

The aim of our research was to study the influence of citrate and sulfate of copper, manganese and zinc on the carbohydrates composition of biomass of the medicinal mushroom Trametes versicolor (L.) Lloyd. cultivated in a liquid medium. The studied strain of Trametes versicolor 353 was obtained from the Culture Collection of Mushrooms (IBK) from the M. G. Kholodny Institute of Botany, National Academy of Sciences of Ukraine. Citrates of copper, manganese and zinc were obtained from the Institute of Nanobiotechnologies and Resource Conservation of Ukraine, Kyiv. In this study we used glucose-peptone-yeast extract medium (GPY) with the following composition of (g/L): glucose – 25, peptone – 3, yeast extract – 3, K2HPO4 – 1, KH2PO4 – 1, MgSO4 ∙ 7H2O – 0.25, distilled water – 1,000 ml; pH 6,5 (control medium). Cu2+ (sulfate form or citrate form) were added to control medium in concentration 4 mg/L, Zn2+ and Mn2+ (sulfate form or citrate form) were added to control medium in concentration 1 mg/L. Mycelium was grown in a submerged culture on a rotary shaker (120 rpm) at 26 °C in 250 ml Erlenmeyer flasks, containing 50 ml of liquid medium. The biomass was harvested after 9 days of cultivation in the liquid medium. Monosaccharides and sugar alcohols was analyzed by high-performance liquid chromatography Agilent 1200 (Agilent technologies, USA). The results of our research demonstrated that the fraction of total carbohydrates from T. versicolor 353, which were cultivated on the control medium, consists of glucose (91.5%), galactose (1.9%), mannose (5.4%), fucose (0.6%) and xylose (0.7%). The adding of sulfate of zinc or copper to the liquid medium didn’t change the content of monosaccharides of T. versicolor 353 biomass relative to the control medium. At the same time, in the medium with citrate of zinc the amount of glucose increased and the amount of mannose decreased relative to the control medium. Xylose and fucose were not detected in this case. In mycelium of T. versicolor 353 that was cultivated in the medium with manganese sulfate or manganese citrate we detected a small amount of ribose. But the content of other monosaccharides didn’t change in the medium with sulfate of manganese. At the same time, the addition of citrate of manganese to the medium raised the amount of mannose and reduced the amount of glucose in the biomass of T. versicolor 353 relative to the control medium. Also copper citrate reduced the content of glucose in mycelium of T. versicolor 353 relative to the control medium. But in this case we detected mannitol and sorbitol in the biomass. This data indicates that synthesis of sugur alcohols in T. versicolor 353 depend on copper ions in bioactive forms of citrate.

The influence of citrate on surface dissolution and alteration of the micro- and nano-structure of biotite

Unraveling the kinetics and mechanisms of K-bearing mineral dissolution in the presence of organic acids on the nanometer scale is important for understanding the effectiveness of organic acids present in most soil environments.

Reductive Leaching of Jarosites by &lt;i&gt;Shewanella putrefaciens -&lt;/i&gt; Influence of Humic Substances and Chelators in Mineral Dissolution

The anaerobic bioreduction of three Fe (III) ores by a type strain of Shewanella putrefaciens has been investigated. The release of ferrous ion indicated the microbial reduction of jarosite and promotes the subsequent secondary mineralization, leading to the formation of various iron-nearing minerals. In addition, the influence of citrate and EDTA in the medium acting as chelating agents, and an electron shuttling molecule were studied. While the citrate and humic substances increased the iron reduction rate, AQDS inhibit the mineral bioreduction and dissolution. S. putrefaciens do not have the necessity of the direct contact between cells and jarosites and, in consequence, cell attachment and biofilm formation on the mineral surface is scant.

Competitive effect of organic anions on phosphorus attenuation capacity of acid mine drainage floc

This study examines the phosphorus attenuation capacity of acid mine drainage (AMD) floc (also called ocher or sludge)—generated by neutralizing AMD with ammonia, lime, and sodium hydroxide—in the face of competition from two major organic companions, citrate and oxalate, of phosphorus in manure. Lime-treated floc (LF) was the least effective of the three flocs in attenuating both inorganic phosphorus and organic phosphorus (OP: represented by inositol hexaphosphate or phytate). Out of the remaining two flocs, ammonia-treated floc (AF) attenuated more inorganic phosphorus and less organic phosphorus than did sodium hydroxide-treated floc (SF). Increasing citrate:phosphorus molar ratio in the solution from 0:1 to 1:1 decreased the inorganic P attenuation capacity (IPAC) from 53 to 29 % in AF, 33 to 16 % in LF, and from 49 % to 27 % in SF at pH 4. The corresponding figures for organic P attenuation capacity (OPAC) were from 73 to 54 % in AF, 58 to 45 % in LF, and from 76 to 58 % in SF. Increasing oxalate:phosphorus molar ratio from 0:1 to 1:1 decreased IPAC and OPAC similarly, but to a lesser extent. The competitive influence of citrate and oxalate went on weakening with increase in pH. A likely increase in pH following prolonged manure application may undermine the competitive ability of citrate and oxalate. The study shows that manure P attenuation potential of waste of AMD treatment, notwithstanding the peer anion competition to P, warrants its effectiveness in controlling buildup of P in heavily manured soils.

The influence of citrate, EDTA, and heparin anticoagulants to human plasma LC–MS lipidomic profiling

Lipid profiling of human plasma by liquid chromatography-electrospray ionization coupled to mass spectrometry (LC–ESI-MS) is being used to identify biomarkers of health, disease, and treatment efficacy. However, there is no consensus on the choice of anticoagulant to perform and compare lipidomic measurements. This study assessed the effect of the anticoagulants citrate, EDTA, and heparin, on eight synthetic and 80 plasma lipids, and compared lipidomic data among anticoagulants. Lipid extraction was affected distinctively by the anticoagulant of choice likely due to the different physico-chemical properties among anticoagulants. Peak areas of seventy endogenous lipids showed significant differences between citrate–heparin and EDTA–heparin comparisons similar to those observed for synthetic lipids. Only ten endogenous lipid species showed comparable peak areas among the three anticoagulants. Correction by a structurally related internal standard only partly eliminated differences among anticoagulants (ANOVA, P value <0.001). However, comparisons among anticoagulants were possible for most endogenous lipids after correction of peak areas by the sum of areas of its lipid class. Our observations indicate that the choice of anticoagulant distinctively impact the peak response of most lipid species by LC–ESI-MS. Lipidomic data from plasma obtained with different anticoagulants should address differences in matrix effects and extraction procedures since ion strength, plasma pH, and different physicochemical properties among anticoagulants influence lipid extraction and LC–ESI-MS analysis.

Study of dissolution kinetics of manganese dioxide in oxalic and citric acids solutions

The paper studies the influence of citrate and oxalates - ions on kinetics of dissolution of manganese dioxide. It is found that the speed of dissolution increases along with concentration of citric and oxalic acids. Orders on citrate and to oxalates - ions are designed. The empirical formulas describing dependence of speed of dissolution from concentration of the specified acids are offered. In order to obtain the optimal modes of leaching of manganous oxide from anthropogenic raw material the authors investigate the influence рН on the speed of MnO2 dissolution in oxalic acid.

Citrate influence on oxidative status of rats tissues under experimental toxic hepatitis

The effect of citrate free-radical oxidation intensity and aconitate hydratase, superoxide dismutase and catalase activities in liver and blood serum of rats with experimental toxic hepatitis has been investigated. Citrate administration to rats with hepatitis decreased biochemiluminescence parameters and conjugated diene content in rats tissues, increased under conditions of CCl4-induced liver damage. At the same time aconitase activity, decreased at the pathology, increases. The superoxide dismutase and catalase activities increased in at experimental toxic hepatitis, tended towards control values after citrate administration.

The influence of citrate, maltolate and fluoride on the gastrointestinal absorption of aluminum at a drinking water-relevant concentration: A 26Al and 14C study

The objectives were to test the null hypotheses that (1) citrate, maltolate, and fluoride do not significantly influence oral Al bioavailability, Cmax or Tmax at an Al dose relevant to drinking water exposure; and (2) Al citrate and maltolate are absorbed intact from the gastrointestinal tract. Male Fisher rats were given 1ml of solution intra-gastrically containing 1 nCi 26Al (65nmol total Al) as the Al3+ ion, or as complexes with 14C-citrate, 14C-maltolate or fluoride, during concurrent 27Al iv infusion. Blood was repeatedly collected for serum 26Al, total Al and 14C quantification. Absorption parameters were estimated using WinNonlin. Al bioavailability, Cmax and Tmax from the ion, citrate, maltolate, and fluoride were 0.29±0.11%, 0.61±0.31%, 0.50±0.25%, and 0.35±0.10%; 659±195, 1073±250, 881±356, and 880±295fg/ml; and 1.2±0.9, 1.0±1.1, 1.3±1.0, and 1.0±0.9h (X±SD) respectively. Serum 14C was ∼100 times higher than 26Al. The results suggest a non-significant enhancement of oral Al bioavailability by citrate and maltolate, some Al complex dissociation in the GI tract, and less absorption of Al than citrate or maltolate. The presence of citrate, maltolate and fluoride, at a similar molar concentration to Al, would not be expected to greatly influence Al absorption from drinking water.

Electroless Deposition of Thin-Film CoB alloys: The Influence of Some Bath Parameters on its Magnetic Behavior

The influence of citrate and glycine at different concentrations on the morphology and magnetic properties of thin film CoB alloys is studied. With both additives, coercivity (Hc) is inversely proportional to the complexant concentration. In deposits obtained from glycine containing baths higher magnetization saturation (Ms) values were obtained (1.3 T). Possibly the higher Ms in deposits grown from glycine baths is due to the low boron content (less than 1%). In deposits obtained in citrate containing baths, the boron content increased until a maximum of c.a. 15 % as the citrate concentration was increased. There are evidences that not only boron but the additive influences microstructure and therefore the magnetic properties of such films.

The role of citrate and phthalate during Co(II) coprecipitation with calcite

The influence of citrate and phthalate on Co coprecipitation with calcite was investigated using a combination of batch experiments, Fourier-transform infra-red (FT-IR) spectroscopy, and thermogravimetric analysis (TGA) over a wide range of precipitation rates. Steady-state growth conditions (at constant [Ca], [Co], DIC, and pH) were generally achieved within 3–5 h, after which Co(II) partitioning into calcite was evaluated. Only minor differences are observed in the partition coefficient ( K d) trends with and without citrate and phthalate as a function of calcite precipitation rate except at very low rates. Slight inhibition of calcite growth is observed in the presence of citrate or phthalate, which can be attributed to adsorption at surface sites. TGA curves for samples coprecipitated with citrate show a significant mass loss between 375 and 550 °C, whereas the weight-loss curves for the Co–phthalate coprecipitates are indistinguishable from those of the organic-free Co coprecipitates. This indicates that citrate is incorporated into calcite during calcite crystallization, whereas phthalate is excluded. FT-IR spectra for the sample with citrate show a broad absorption in the range 3700–3100 cm −1, which is attributable to water molecules coordinated to citrate coprecipitated with calcite. The preferential incorporation of citrate over phthalate likely reflects differences in both aqueous speciation and conformation of the carboxylate groups. This new finding may provide new insight to the factors that control the behavior of macromolecules and their incorporation into the structure of calcium carbonate during biomineralization.