Changes In Solute Concentration Research Articles

Effect of mass transfer processes on accumulation and crystallization of boric acid in WWER core in emergency cases

In this paper the processes of boric acid mass transfer in a WWER-TOI nuclear reactor in case of the accidents with main coolant circuit rupture and operation of passive safety systems (the hydro accumulators systems of the first, second and third stages, as well as the passive heat removal system) are considered. The results of the calculation of changes in the boric acid solution concentration in the core for the WWER emergency mode are presented. According to the results of the calculation a significant excess of the ultimate concentration of boric acid in accidents with main coolant circuit rupture after 43 hours of emergency mode is observed. The positive influence of the boric acid droplet entrainment on the processes of its crystallization and accumulation in the core is shown. The mass of boric acid deposits on the internals is determined. The received results allow concluding that the accumulation and crystallization of boric acid in the core may lead to blocking the flow cross section and to deterioration of heat removal from fuel rods. The necessity of an experimental studies of the processes of boric acid drop entrainment under conditions specific to the WWER emergency modes is shown.

Comparing in situ colorimetric DET and DGT techniques with ex situ core slicing and centrifugation for measuring ferrous iron and dissolved sulfide in coastal sediment pore waters

In productive coastal sediments the separation between different biogeochemical zones (e.g. oxic, iron(III)-reducing and sulfate-reducing) may be on the scale of millimetres. Conventional measurement techniques simply cannot resolve changes in pore water solute concentrations over such small distances. The diffusive equilibration in thin films (DET) and the diffusive gradients in thin films (DGT) techniques allow in situ determination of pore water solute concentration profiles with one-dimensional profiles and/or two-dimensional distributions on the millimetre scale. Here we compare measurements of pore water iron(II) and sulfide using conventional core sampling (slicing and centrifugation) and colorimetric DET-DGT techniques. DET-DGT samplers were deployed within replicate sediment cores from three different sites, which were processed by slicing and centrifugation following retrieval of the samplers, so that the measurements were approximately co-located. Iron(II) concentrations were determined by DET at all three sites (0.3–262 μmol L−1), while dissolved sulfide was consistently measured by DGT at one site only (0.003–112 μmol L−1). Pore water concentrations of iron(II) and sulfide determined conventionally following pore water extraction (iron(II); 0.4–88 μmol L−1 and sulfide; 0.05–36 μmol L−1), were systematically lower than the colorimetric DET and DGT measurements in the same sample. This underestimation was most likely due to the mixing of sediment from different biogeochemical zones during pore water extraction, which resulted in the precipitation of iron(II) and sulfide. This study shows that conventional pore water extraction methods can be unreliable for the determination of redox-active solutes due to artefacts associated with pore water mixing.

The rheological anomaly in water-silicate systems: a possible thermodynamic explanation

A rheological anomaly, consisting in the reversible increase in solution viscosity with increasing temperature, is a typical property of aqueous solutions of aminosilicates (polysilicates of aliphatic amines, amino alcohols and other amino compounds). To explain this anomaly, a simple mathematical model of interrelated acid-base and polycondesation equilibria in such solutions is proposed. The proposed calculation model assumes a direct dependence of the solution viscosity on the polymerization degree of silicate anions, as well as the independence of the dissociation constant of silanols and the polycondensation equilibrium constant on the degree of anions polymerization. Based on the assumptions made, a system of eight linear and nonlinear equations was constructed and solved. The results of calculations performed for concentrated solutions of aminosilicates (methylamine and piperidine silicates), as well as sodium and tetramethylammonium silicates, confirm the presence of a positive temperature dependence of the polymerization degree of silicate anions in the aminosilicate solutions, in contrast to the solutions of silicates of the strong bases. Thus, the proposed mathematical model of polymerization-hydrolysis equilibria in aqueous silicate solutions qualitatively explains the existence of the rheological anomaly in aqueous solutions of aminosilicates and its absence in solutions of alkali silicates and silicates of quaternary ammonium bases. In addition, this model correctly reproduces the displacements of the molecular mass distribution of silicate anions with changes in chemical composition and concentration of solutions. The proposed approach makes it possible to clarify the mechanism of the rheological anomaly, to understand the roles of various thermodynamic factors in its occurrence, and, as a consequence, to conduct a more meaningful search for new silicate and non-silicate systems with the same anomaly.

The role of eddies in solute transport and recovery in rock fractures: Implication for groundwater remediation

AbstractA better understanding of solute transport and retention mechanism in rock fractures has been challenging due to difficulty in their direct observations in microscale rough‐walled fractures. Six representative troughs in a rough‐walled fracture were selected for microscale observations of eddy formation with increasing flow velocity and its effect on spatiotemporal changes of solute concentration. This experimental study was enabled by a microscale visualization technique of micro particle image velocimetry. With increasing flow velocity (Re ≤ 2.86), no eddies were generated, and solutes along the main streamlines transported rapidly, whereas those near the wall moved slowly. A larger amount of solutes remained trapped at all troughs at Re = 2.86 than Re < 1. For Re = 8.57, weak eddies started to be developed at the troughs on the lee side, which little contributed to overall solute flushing in the fracture. Accordingly, a large of amount of water was needed for solute flushing. The flow condition of 1 < Re < 10, before a full development of eddies, was least favourable in terms of time and amount of remediation fluid required to reach a target concentration. After large eddies were fully developed at troughs on the lee side for Re = 17.13, solutes were substantially reduced by eddies with less amount of water. Fully developed eddies were found to enhance solute transport and recovery, as opposed to a general consensus that eddies trap and delay solutes. Direct inflow into troughs on the stoss side also made a great contribution to solute flushing out of the troughs. This study indicates that fully developed eddies or strong inflows at troughs are highly possible to form for Re > 10 and this flow range could be favourable for efficient remediation.

From Starting Formation to the Saturation Content of the β-Phase in Poly(9,9-dioctylfluorene) Toluene Solutions

In this research, the relationship between chain aggregation and poly(9,9-dioctylfluorene) (PFO) β-phase content with a change of the PFO solution concentration is investigated. Photoluminescence and UV–vis absorption spectra are used to explore the PFO β-phase and its content. Chain aggregation is explored by dynamic light scattering (DLS). It is found that the chain aggregation size of the starting to form PFO β-phase is approximately 100 nm. The β-phase content increases with the chain aggregation degree. When the β-phase content is in the range of 44% ± 2%, the maximum value of the content (saturation content) of the β-phase is reached and cannot be changed by any external field that could induce β-phase formation. Therefore, the concept of the saturation content of the PFO β-phase is first proposed. The mechanism from PFO β-phase formation to saturation content is explored by DLS and atomic force microscopy. This research is significant to understand and control the molecular chain condensed-state process as well as phase transition from solution to film to achieve a photoelectric device with high charge carrier mobility, stability, and efficiency.

Utilização de efluente tratado em complexo industrial automotivo

RESUMO Neste trabalho, realizaram-se modificações nos sistemas produtivo e de tratamento de efluentes em um complexo industrial automotivo a fim de possibilitar a utilização do efluente tratado no sistema de torres de resfriamento. Inicialmente, realizou-se um balanço hídrico nos processos industriais para determinar o consumo de água e analisou-se a qualidade do efluente tratado quanto aos parâmetros físico-químicos em dois pontos do sistema de tratamento de efluentes: no decantador secundário (P1) do tratamento físico-químico e na saída da lagoa de polimento (P2). Essas análises mostraram que o efluente tratado no decantador secundário não tem capacidade de atender às especificações da água de circulação das torres de resfriamento sem a realização de muitas alterações em seu tratamento, optando-se pela utilização do efluente tratado na saída da lagoa de polimento após modificações, como: alteração na concentração de ácido fosfórico e de ácido nítrico da solução de limpeza dos tanques de fosfatização, elevação em 50% da capacidade de aeração da lagoa aerada e troca do coagulante sulfato de alumínio pelo cloreto férrico no tratamento físico-químico. Assim, os parâmetros do efluente tratado na lagoa de polimento aproximaram-se aos parâmetros especificados para água de torres de resfriamento. A introdução desse efluente na proporção de 40% do volume da água de circulação na torre de resfriamento resultou em elevação do ciclo de dureza e redução no ciclo de sílica. A utilização de um filtro abrandador na saída da lagoa de polimento proporcionou a redução dos parâmetros de qualidade da água para valores similares aos da água de recirculação nas torres de resfriamento.

Hydrated Micellar Structure of Ethoxylated Nonyl Phenols from PGSE NMR

Abstract Solvent self-diffusion coefficients $D_{w}^{*}$ and Dw are respectively determined by PGSE NMR in the bulk solvent and in suitably prepared aqueous micellar solutions of a series of commercial ethoxylated nonyl phenols (ENPs) at 298 and 317 K. The capability of ENP micelles for obstructing the free diffusion of solvent molecules is characterized by the obstruction ratio $K = D_{w}/D_{w}^{*}$, which turns out to depend merely on the volume fraction of EO units present—regardless of significant changes in solute concentration, distribution of EO chain length, micellar aggregation number and temperature. The experiments are interpreted in terms of a renewed analytical model of ENP micellar structure, based on Tanford’s concept of hydrodynamic particle. The results from model fitting return the characteristic sizes of ENP monomers, support the ellipsoid shape of the micelles, indicate a stable EO shell, follow the trend in the variation of hydration number vs. the chain length predicted by thermal analysis in PEO solutions.

Nanoscale monolayer adsorption of polyelectrolytes at the solid/liquid interface observed by quartz crystal microbalance

The adsorption properties of cationic polyelectrolytes (poly (diallyl dimethylammonium chloride) (PDDA) and poly (allylamine hydrochloride) (PAH)) on solid surfaces were observed using quartz crystal microbalance. The response of adsorption was different with the change of polyelectrolyte solution concentration and pH value. The influence of pH value on the PDDA adsorption process is inconspicuous, while PAH shows strong dependence on the pH value. Furthermore, the change of molecular conformation of polyelectrolyte molecule is the main factor that affects the adsorption properties and structures.

Measurements of Concentration differences between Liquid Mixtures using Digital Holographic Interferometry

Abstract We present an alternative method to detect and measure the concentration changes in liquid solutions. The method uses Digital Holographic Interferometry (DHI) and is based on measuring refractive index variations. The first hologram is recorded when a wavefront from light comes across an ordinary cylindrical glass container filled with a liquid solution. The second hologram is recorded after slight changing the liquid’s concentration. Differences in phase obtained from the correlation of the first hologram with the second one provide information about the refractive index variation, which is directly related to the changes in physical properties related to the concentration. The method can be used − with high sensitivity, accuracy, and speed − either to detect adulterations or to measure a slight change of concentration in the order of 0.001 moles which is equivalent to a difference of 0.003 g of sodium chloride in solutions. The method also enables to measure and calculate the phase difference among each pixel of two samples. This makes it possible to generate a global measurement of the phase difference of the entire sensed region.

Performance of Egg-Shell and Fish-Scale as Adsorbent Materials for Chromium (VI) Removal from Effluents of Tannery Industries in Eastern Uganda

The performance of egg-shells and fish-scales biomaterials in separating chromium (VI) ions from tannery effluents obtained from tannery industries in Jinja town of Eastern Uganda was investigated. Using crushed egg-shell and fish-scales as adsorbents, sorption tests were carried out to determine the effects of bio-sorbent concentration and particle size on chromium (VI) removal. The adsorbate concentration in the tannery effluents before and after adsorption was analyzed using the UV-vis Spectrophotometer at wavelength of 540 nm. The adsorbent concentration was calculated from concentration change in aqueous solution before and after equilibrium sorption. Results showed that chromium (VI) ions adsorb on the surfaces of both biomaterials. The optimum conditions for chromium (VI) removal were found at pH of 6.8, particle size of 300 μm and bio-sorbent concentration of 0.5 g. The correlation coefficient (R2) showed that chromium (VI) adsorption fitted Langmuir adsorption isotherms. It was concluded that the adsorption process of chromium (VI) on the fish-scales and egg-shells was highly feasible.

Kinetics of Pressure Cycling Extraction of Solute from Leaves of Mate (Ilex paraguariensis) Dispersed in Water

A set of seven extraction experiments was performed to investigate the influence of pressure cycles on the kinetics of solute removal from leaves of mate dispersed in water. The mass ratio of liquid to dry solid (40), the temperature (32°C), and time of extraction (3600 s) were not varied. Five extraction runs were under cyclic pressurization (1 cycle = 300 s at 91.4 kPa + 300 s at 182.8 kPa) and stirring speeds (S) of 0, 150, 500, 1500, and 2000 rpm, while the two other ones were at constant pressure (182.8 kPa) and S close to 1500 and 2000 rpm. Based on seven pairs of parameters of a reliable second-order kinetic model (R2 ≥ 0.967), cyclic pressurization had no effect on equilibrium and kinetics of extraction (p > 0.05) when the role of convection on solute transfer was negligible (S ≥ 500 rpm). In the stirring speed range from 500 to 2000 rpm, the operation was controlled by diffusion (Bi > 1.7 × 103), so a transient two-dimensional diffusion model was able to describe correctly the changes of solute concentration with time. Below 500 rpm, solute transfer was governed by a combination of diffusion and convection with the external resistance to mass transfer as a function of S (16 ≤ Bi ≤ 28).

Electric Bipole Antenna Model Study of a Basin Scale Fault System

The generation of electric fields with electric bipole transmitters are applicable at a wide range physical scales and for many subsurface exploration endeavors. Increase in transmitter power for a wide range of waveforms combined with receiver sensitivity has led to deeper exploration with electromagnetic methods. We investigate the optimal design of grounded bipole EM system for generation of electromagnetic fields over a basin-scale fault in Perth, W.A. The technical objective is to recover detailed electrical conductivity distribution proximal to and within a large fault system to depths of as much as 1000m below the surface. The ultimate geological imperative for the exercise is reveal possible change in solute concentration or hydraulic across these large fault systems. For example, imaging of the difference composition of fault core zone would be a valuable outcome. We investigate various combinations of receiving and transmitting antenna geometries in preparation for a field campaign intended to r...

Well-ordered vertically aligned ZnO/CdS core/shell nanowires with enhanced photocatalytic performance

Well-ordered vertically aligned ZnO/CdS core/shell nanowires (NWs) were successfully synthesized on Si substrates through two-step ion exchange approaches. The morphology, crystal structure and composition were characterized by scanning electron microscope, X-ray diffraction, and high-resolution transmission electron microscope. The shell thickness can be easily tuned between 10 and 25nm via changing ion exchange time and solution concentration. It is found that ZnO/CdS core/shell NWs exhibit enhanced light-harvesting ability in both UV and visible light range which leads to improved photocatalytic performance as compared to bare ZnO. In addition, the mechanism of the photo-performance is discussed to illustrate the efficiency enhancement of ZnO/CdS photocatalysts.

Spatial model of convective solute transport in brain extracellular space does not support a "glymphatic" mechanism.

A "glymphatic system," which involves convective fluid transport from para-arterial to paravenous cerebrospinal fluid through brain extracellular space (ECS), has been proposed to account for solute clearance in brain, and aquaporin-4 water channels in astrocyte endfeet may have a role in this process. Here, we investigate the major predictions of the glymphatic mechanism by modeling diffusive and convective transport in brain ECS and by solving the Navier-Stokes and convection-diffusion equations, using realistic ECS geometry for short-range transport between para-arterial and paravenous spaces. Major model parameters include para-arterial and paravenous pressures, ECS volume fraction, solute diffusion coefficient, and astrocyte foot-process water permeability. The model predicts solute accumulation and clearance from the ECS after a step change in solute concentration in para-arterial fluid. The principal and robust conclusions of the model are as follows: (a) significant convective transport requires a sustained pressure difference of several mmHg between the para-arterial and paravenous fluid and is not affected by pulsatile pressure fluctuations; (b) astrocyte endfoot water permeability does not substantially alter the rate of convective transport in ECS as the resistance to flow across endfeet is far greater than in the gaps surrounding them; and (c) diffusion (without convection) in the ECS is adequate to account for experimental transport studies in brain parenchyma. Therefore, our modeling results do not support a physiologically important role for local parenchymal convective flow in solute transport through brain ECS.

Synthesis of Au@CdS core–shell nanoparticles and their photocatalytic capacity researched by SERS

High-quality Au@CdS core–shell nanoparticles (CSNs) have been synthesized to improve photo-conversion efficiency in photocatalysis. They demonstrate higher photocatalytic activity in the experiment of photocatalytic degradation of rhodamine 6G (R6G) solution than that of CdS counterparts. Au@CdS CSNs can broaden the absorption range in visible region compared to CdS counterparts. The heterojunction interface between Au and CdS facilitates the separation of photo-generated electron–hole pairs, and transfers electrons from CdS region to Au core. The two advantages are crucial to improve the photocatalytic activity of Au@CdS CSNs. Charge transfer mechanism between metal and semiconductor is efficient that can be used to guide the design of photocatalysts, photovoltaics, and other optoelectronic devices to effectively utilize the solar power. In this paper, we research the photocatalytic process by surface-enhanced Raman scattering (SERS). The combination of photocatalysis and SERS not only can show the change in concentration of R6G solution, but also can provide the information of the change of R6G molecular structure in photocatalytic process.

A model for the evolution in water chemistry of an arsenic contaminated aquifer over the last 6000 years, Red River floodplain, Vietnam

Aquifers on the Red River flood plain with burial ages ranging from 500 to 6000years show, with increasing age, the following changes in solute concentrations; a decrease in arsenic, increase in Fe(II) and decreases in both pH, Ca and bicarbonate. These changes were interpreted in terms of a reaction network comprising the kinetics of organic carbon degradation, the reduction kinetics of As containing Fe-oxides, the sorption of arsenic, the kinetics of siderite precipitation and dissolution, as well as of the dissolution of CaCO3. The arsenic released from the Fe-oxide is preferentially partitioned into the water phase, and partially sorbed, while the released Fe(II) is precipitated as siderite. The reaction network involved in arsenic mobilization was analyzed by 1-D reactive transport modeling. The results reveal complex interactions between the kinetics of organic matter degradation and the kinetics and thermodynamic energy released by Fe-oxide reduction. The energy released by Fe-oxide reduction is strongly pH dependent and both methanogenesis and carbonate precipitation and dissolution have important influences on the pH. Overall it is the rate of organic carbon degradation that determines the total electron flow. However, the kinetics of Fe-oxide reduction determines the distribution of this flow of electrons between methanogenesis, which is by far the main pathway, and Fe-oxide reduction. Modeling the groundwater arsenic content over a 6000year period in a 20m thick aquifer shows an increase in As during the first 1200years where it reaches a maximum of about 600μg/L. During this initial period the release of arsenic from Fe-oxides actually decreases but the adsorption of arsenic onto the sediment delays the build-up in the groundwater arsenic concentration. After 1200years the groundwater arsenic content slowly decreases controlled both by desorption and continued further, but diminishing, release from Fe-oxide being reduced. After 6000years the arsenic content has decreased to 33μg/L. The modeling enables a quantitative description of how the aquifer properties, the reactivity of organic carbon and Fe-oxides, the number of sorption sites and the buffering mechanisms change over a 6000year period and how the combined effect of these interacting processes controls the groundwater arsenic content.

Magmatic and post-magmatic phenomena in the Karkonosze granite and its metamorphic envelope (West Sudetes, SW Poland)

AbstractMineralogical studies of the Karkonosze granite (ca. 322-312 Ma) and its surroundings in West Sudetes (SW Poland) have provided data on Nb-Ta-REE minerals from pegmatites in the NE part of the pluton and several new finds of Ag minerals and 15 oxygenic Bi phases, hitherto not reported from the massif. The Karkonosze pegmatites are enriched in HREE as fergusonite-(Y) or xenotime-(Y) appear in almost every studied pegmatite, together with a subordinate assemblage of the aeschynite, euxenite or columbite group. The abundance of LREE minerals such as allanite-( Ce) and the monazite group, correlates inversely with the Nb-Ta-Ti minerals, whilst an early generation of monazite-(Ce) revealed an exceptionally high amount of Nd (up to 22 wt.% of Nd2O3). The physical and chemical conditions during the magmatic and post-magmatic processes were reconstructed and the effects of contact metamorphism in amphibolites from hornfelsed zones examined. Changes in solution composition and concentration at the early magmatic stage (825-920°C), pegmatitic stage overlapping with hydrothermal (560°C which ended at 160-90°C) and clearly hydrothermal stage (400 to 110°C) were studied in detail by means of melt and fluid inclusions in quartz. Furthermore, post-magmatic fluids, including some enriched in Li and B, were identified in rock-forming quartz from the whole pluton. In turn, study of the amphibolites indicates that the pair cummingtonite + anorthite or the presence of Ca-rich plagioclase with actinolite seem to be reliable mineral proxies of the thermal impact of the granitoid body on amphibolites in its envelope. The inferred conditions of the contact processes (450-550°C, 2.5- 4.8 kbar) point to an elevated geothermal gradient (ca. 32-45°C/km) probably reflecting the heat flow induced by the Karkonosze intrusion. Moreover, despite the textural and mineral changes imposed by regional and contact metamorphism, the amphibolites have their pre-metamorphic (magmatic) geochemical features undisturbed.

Interfacial Adsorption of Silk Fibroin Peptides and Their Interaction with Surfactants at the Solid-Water Interface.

Regenerated silk fibroin (RSF) is a Food and Drug Administration-approved material and has been widely used in many biomedical and cosmetic applications. Because of the amphiphilic nature of the primary repeat amino acid sequence (e.g., AGAGAS), RSF peptides can significantly reduce the water surface tension and therefore have the potential to be used as a surface active component for many applications, particularly in the biomedical, cosmetic, pharmaceutical, and food industries. In this paper, the adsorption of RSF peptides separated into molecular fractions of 5-30, 30-300, and >300 kDa has been studied at the solid-water interface by neutron reflection and spectroscopic ellipsometry to assess its surface active behavior. A stable layer of RSF was found to be irreversibly adsorbed at the hydrophilic SiO2-water interface. Changes in solution concentration, pH, and ionic strength all had an impact on the final adsorbed amount found at the interface. There were no significant differences between the final adsorbed amounts or layer structure among the three RSF molecular fractions studied; however, >300 kDa RSF was more stable to changes in solution ionic strength. Adsorption of conventional anionic and cationic surfactants, sodium dodecyl sulfate (SDS) and dodecyl trimethylammonium bromide (C12TAB), to the preadsorbed 5-30 kDa RSF revealed penetration of the surfactant into the RSF layer, at concentrations below the critical micellar concentration (CMC). SDS was found in the preadsorbed RSF layer and gradually removed RSF from the surface with an increase in SDS concentration. At concentrations above the CMC, there is near complete removal of RSF by SDS at the interface. C12TAB adsorbed into the preadsorbed RSF layer with considerably less removal of RSF from the interface compared to SDS. At concentrations above the CMC, both C12Tab and RSF were found to coexist at the interface, forming a less thick layer but with a considerable amount of RSF still present.

A Rheological Study of Xanthan Polymer for Enhanced Oil Recovery

ABSTRACTThis study explored the potential application of xanthan gum as a polymer-flooding agent for oil recovery applications in a specific Devonian oil field. Rheological measurements using oscillatory and steady shear were carried out to examine the change in shear viscosity when the polymer was applied under reservoir conditions. The xanthan rheological properties were described by the Herschel–Bulkley and Ostwald models to characterize its non-Newtonian behavior. As expected, the results showed that higher xanthan concentrations raised the polymer viscosity and increased the degree of shear thinning. Addition of alkalis caused the viscosity of the xanthan solutions to decrease, but they maintained their shear-thinning properties. Polymer solutions in typical oil field brine increased in viscosity by ca. 400% for 720 hours storage time. On the other hand, as expected, the solutions lost their viscosity gradually with increasing temperature. However, at reservoir temperature (68°C), the polymer solutions kept more than 60% of their initial viscosity. In oscillatory deformation tests it was observed that all the measured viscoelastic properties were influenced by temperature and confirmed that xanthan solution behaved as a weak-gel. An order-disorder transition exists within the xanthan-brine solutions which responds to changes in solution concentration, temperature and alkalis.

ESI FT-MS and DFT studies of aqueous Au(I) complexes with cysteine and its disulfide form cystine

Aqueous complexes of [Au(CySSCy)(CySH)n]+ containing gold(I), cysteine (CySH) and the disulfide cystine (CySSCy) have been examined by electrospray ionization (ESI) Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry, and the identities of individual Au complexes have been confirmed by infrared multiphoton dissociation (IRMPD)- and collision-induced dissociation (CID) experiments. Results from positive-mode ESI–MS experiments show that the aqueous Au(III)/cysteine system has a strong tendency to auto-oxidize toward cystine and form aurous-disulfide complexes of the type [Au(CySSCy)]+ and [Au(CySSCy)(CySH)n]+. An examination of the concentration- and time-dependent complexation behavior of Au(I) with CySSCy and CySH shows that the abundance of [Au(CySSCy)(CySH)]+ and [Au(CySSCy)(CySH)2]+ increases with increasing ESI solution concentration, consistent with the aqueous ionization of cysteine at pKa1=1.92. In general, the response of individual ESI mass spectra of [Au(CySSCy)(CySH)n]+ to changes in solution concentration is indicative of a direct correlation between gas-phase and aqueous Au speciation, a feature that is likely rooted in gold complexation processes occurring in solution prior to electrospraying. Finally, equilibrium geometries of Au(I) complexes with cystine and cysteine have been predicted using M06 and PCM/TD-DFT calculations, and these results have been employed to predict stepwise complexation energies of [Au(CySSCy)(CySH)n]+ and to pinpoint the most important UV–vis absorption features in aqueous solution.