H2O Vapor Pressure Research Articles

Microstructure and strength of microporous MgO refractory aggregates with nano-sized pores

ABSTRACT In this work, microporous MgO refractory aggregates with nano-sized pores were prepared by in situ decomposition method using Mg(OH)2 as raw material. The effects of firing temperatures (1600–1700°C) and compacting pressures (100–200 MPa) on the microstructures and properties of microporous MgO refractory aggregates were thoroughly studied. The results showed that the microporous MgO refractory aggregates contained two types of pore structures, which were intra-particle pores with pore sizes of 180.0–230.0 nm formed by in situ decomposition of Mg(OH)2 and inter-particle pores with pore sizes of 1.5–3.0 μm derived from particle packing between Mg(OH)2 pseudomorph particles, respectively. Besides, the firing temperatures had a great influence on the intra-particle pore size and microcrystallite size. And the compacting pressures not only influenced the intra-particle pore size via packing behaviors but also affected the inner firing behaviors of the pseudomorph particles due to the increase in H2O vapor pressure. Overall, at a compacting pressure of 150 MPa and firing temperature of 1650°C, the sample had the best comprehensive performance with a bulk density of 1.92 g/cm3, a compressive strength of 11.9 MPa, an apparent porosity of 45.0%, a relative aggregate tube strength of 25.2% and a median pore size of 262.3 nm.

Copper in Hydrothermal Systems: a Thermodynamic Description of Hydroxocomplexes

The experimental data available in the literature on the solubility of Cu(met.) and Cu2O (cuprite) in water under hydrothermal conditions have been processed. Key experiments were carried out on the solubility of cuprite at 300 C, saturated vapor pressure of H2O, vs. pH of the solution. As a result, a set of values of thermodynamic properties for 25°C, 1 bar and parameters of the HKF (Helgeson-Kirkham-Flowers) and AD (Akinfiev-Diamond) equation of states for Cu(I) hydroxocomplexes was obtained, which make it possible to describe their behavior in a wide range of temperatures (0 – 600 C), pressures (1 – 3000 bar) and densities of aqueous fluid (0.01 – 1 gcm–3). As it has been shown by thermodynamic modeling the Cu+ ion is prevalent in the acidic and weakly alkaline regions of the aqueous solvent over the entire temperature and pressure range studied. The effect of the neutral CuOH hydroxocomplex begins to show up in the alkaline region at T 300 C and grows with increasing temperature. The second copper hydroxocomplex Cu(OH)2– shows up only in the strongly alkaline region, and the temperature has almost no effect on its behavior

High crystalline hydroxyapatite coating by eclipse type pulsed-laser deposition for low annealing temperature

The eclipse type pulsed-laser deposition (PLD) scheme as a droplet-eliminated method with irradiation on a β-tricalcium phosphate (β-TCP) slab target was employed to achieve high density without holes, high purity, and high crystallinity hydroxyapatite (HAp) coating on a zirconia substrate with a low annealing temperature under an H2O vapor pressure. An obstacle ball was set between the target and the substrate so that ablated droplets would collide with the ball and be eliminated, while other ablated atoms went around the ball and were deposited on the substrate. A flat, transparent, and high-density coating layer was deposited on the substrate in an H2O vapor atmosphere at 0.1 Torr for different substrate surface temperatures from 20 °C to 650 °C. The phase of the coating layers was significantly changed from amorphous calcium phosphate to crystalline HAp when the temperature was set to over 360 °C, as determined from Raman microscopy measurements. Raman spectroscopy also showed that the HAp crystal size became larger as the temperature was increased to over 360 °C. It was concluded that the eclipse type PLD method with irradiation on a β-TCP target would improve the quality of HAp coatings and allow effective lowering of the annealing temperature.

A tenuous, collisional atmosphere on Callisto

A simulation tool which utilizes parallel processing is developed to describe molecular kinetics in 2D, single- and multi-component atmospheres on Callisto. This expands on our previous study on the role of collisions in 1D atmospheres on Callisto composed of radiolytic products (Carberry Mogan et al., 2020) by implementing a temperature gradient from noon to midnight across Callisto’s surface and introducing sublimated water vapor. We compare single-species, ballistic and collisional O2, H2 and H2O atmospheres, as well as an O2+H2O atmosphere to 3-species atmospheres which contain H2 in varying amounts. Because the H2O vapor pressure is extremely sensitive to the surface temperatures, the density drops several orders of magnitude with increasing distance from the subsolar point, and the flow transitions from collisional to ballistic accordingly. In an O2+H2O atmosphere the local temperatures are determined by H2O near the subsolar point and transition with increasing distance from the subsolar point to being determined by O2. When radiolytically produced H2 is not negligible in O2+H2O+H2 atmospheres, this much lighter molecule, with a scale height roughly an order of magnitude larger than that for the heavier species, can cool the local temperatures via collisions. In addition, if the H2 component is dense enough, particles originating on the day-side and precipitating into the night-side atmosphere deposit energy via collisions, which in turn heats the local atmosphere relative to the surface temperature. Moreover, the difference between H2 atmospheric escape rates in single-species and multi-species atmospheres is small: the H2 only has to diffuse through a few hundred km of the heavier gases before it is the lone species in the atmosphere out to the Hill sphere. Finally, we discuss the potential implications of this study on the presence of H2 in Callisto’s atmosphere and how the simulated densities correlate with expected detection thresholds at flyby altitudes of the proposed JUpiter ICy moons Explorer (JUICE) spacecraft.

Crystalline hydroxyapatite coating by hydrolysis using β-tricalcium phosphate target by pulsed-laser deposition

Α β-tricalcium phosphate target was employed to decrease the annealing temperature for crystalline hydroxyapatite coating through a hydrolysis process by pulsed-laser deposition. The crystalline hydroxyapatite content of calcium phosphate coating layers was quantitatively evaluated using Raman spectroscopy and X-ray diffraction, and compared with that of pure polycrystalline powder. Calcium phosphate changes from an amorphous phase to crystalline hydroxyapatite through a crystalline α-tricalcium phosphate phase at around 400 °C under an H2O vapor pressure of 0.1 Torr. The crystalline hydroxyapatite content increases steeply by hydrolysis at 500 °C as the H2O vapor pressure is increased from vacuum to 0.15 Torr, but then decreases somewhat at higher pressure. These results indicate that excessive gas pressure blocks small ablated particles such as atoms, ions, molecules, and clusters that would typically be completely hydrolyzed instantaneously following deposition on the substrate.

A model of the 3-μm hydration band with Exponentially Modified Gaussian (EMG) profiles: Application to hydrated chondrites and asteroids

We present here a new method to model the shape of the 3-μm absorption band in the reflectance spectra of meteorites and small bodies. The band is decomposed into several OH/H2O components using Exponentially Modified Gaussian (EMG) profiles, as well as possible organic components using Gaussian profiles when present. We compare this model to polynomial and multiple Gaussian profile fits and show that the EMGs model returns the best rendering of the shape of the band, with significantly lower residuals. We also propose as an example an algorithm to estimate the error on the band parameters using a bootstrap method. We then present an application of the model to two spectral analyses of smectites subjected to different H2O vapor pressures, and present the variations of the components with decreasing humidity. This example emphasizes the ability of this model to coherently retrieve weak bands that are hidden within much stronger ones.

Vapor Pressure Measurement of Ternary Systems LiCl + [Emim]Cl + H2O, LiBr + [Emim]Cl + H2O, and LiCl + [Emim]Br + H2O

1-Ethyl-3-methylimidazolium chlorine ([Emim]Cl) and 1-ethyl-3-methylimidazolium bromide ([Emim]Br) as an additive to working fluid [lithium bromide aqueous solution (H2O/LiBr) and lithium chloride aqueous solution (H2O/LiCl)] of absorption cycles were proposed. The vapor pressure of H2O + LiCl + [Emim]Cl (mass ratio LiCl/[Emim]Cl = 2) in the temperature from 314.79 to 435.48 K, H2O + LiCl + [Emim]Br (mass ratio LiCl/[Emim]Br = 2) in the temperature from 317.62 to 431.27 K, and H2O + LiBr + [Emim]Cl (mass ratio LiBr/[Emim]Cl = 2) in the temperature from 303.10 to 409.91 K was measured by the boiling point method. The mass fractions of the absorbent were from 0.30 to 0.60. The experimental data were regressed using the Antoine-type equation, and the average absolute relative deviation (AARD %) between the experimental data and calculated values of three systems was 0.44, 0.51, and 0.54%. Compared with that of the previously reported ionic liquids, ([Emim]Ac) as an absorbent for LiBr + H2O, vapor pressure of...

H2O-content and temperature limit the explosive potential of rhyolite magma during Plinian eruptions

Recent rhyolite eruptions on Earth have demonstrated their capacity to produce a multitude of hazards, including ash formation lasting months and impacting the large reaches of the southern hemisphere. Nevertheless, the underlying mechanisms driving these eruptions are not yet fully understood. Magmatic volatiles, especially H2O, dictate whether volcanic eruptions proceed explosively or effusively. Experimental evidence for the role played by H2O in driving explosive fragmentation is rare, in particular in the eruption of rhyolitic magma. Here we show that when hydrous rhyolitic obsidians from Chaitén Volcano (Chile) are experimentally heated above their glass transition temperatures at ambient 1 atm-conditions, two different behaviors result, depending on starting H2O concentration and temperature: obsidians vesiculate to stable or quasi-steady state foams when H2O is ≤1 wt.% for a wide range of temperatures (728–1032°C), but will explode within just tens of seconds (<30 s) of the foaming process when H2O is 1.4 wt.% and T is >874°C. Explosive activity occurs above Chaitén's estimated eruption temperature but, for lower temperatures, only foaming occurs. Whether a foaming sample remains coherent or explodes depends on two interrelated factors, the Peclet number (Pe), a dimensionless ratio of diffusive and viscous timescales, and the timescale or rate of decompression, which is dictated in part by the H2O-vapor pressure gradient between bubbles and atmosphere. At or above 1.4 wt.% H2O, and for a range of permissible Chaitén eruption temperatures (∼780–825°C), Pe is large (>10), meaning viscous deformation aiding vapor expansion is the dominant mode of growing bubbles. Consequently, vesiculation can proceed rapidly due to high initial overpressure and low melt viscosity, until the point is reached that the melt deforms at a rate greater than its relaxation rate, resulting in fragmentation. Below 1.4 wt.% H2O and for temperatures equal to or lower than Chaitén's eruption, decompression and deformation rates, inferred from experimental clast expansion and bubble growth behavior, are at least an order of magnitude smaller than the explosive cases, which is insufficient for critical melt-rupturing. Pe estimations highlight the first order influence of temperature and H2O content on physical degassing behavior. Since the starting H2O content and temperature dictate many the parameters that govern bubble growth—pressure gradient, melt viscosity, and chemical diffusivity—our experiments shed light on what limits fragmentation in natural eruptions and offer an alternative explanation for H2O contents measured in Plinian fall deposits from Chaitén and other rhyolite centers. In essence, pyroclastic obsidian H2O contents could reflect temperature and P-H2O limitations on fragmentation. Furthermore, since foam expansion under low-P, high-T-H2O conditions can foster strain rates in excess of the melt's relaxation rate and thus drive fragmentation, we contend that, in addition to rapid magma ascent (and high magma supply rates), rapid clast expansion under low pressure conditions may also be important for explosive magma fragmentation.

The influence of HCl on the evaporation rates of H2O over water ice in the range 188 to 210 K at small average concentrations

Abstract. The evaporation flux Jev(H2O) of H2O from HCl-doped typically 1.5 µm or so thick vapor-deposited ice films has been measured in a combined quartz crystal microbalance (QCMB)–residual gas mass spectrometry (MS) experiment. Jev(H2O) has been found to show complex behavior and to be a function of the average mole fraction χHCl of HCl in the ice film ranging from 6×1014 to 3×1017 molecule cm−2 s−1 at 174–210 K for initial values χHCl0 ranging from 5×10-5 to 3×10-3 at the start of the evaporation. The dose of HCl on ice was in the range of 1 to 40 formal monolayers and the H2O vapor pressure was independent of χHCl within the measured range and equal to that of pure ice down to 80 nm thickness. The dependence of Jev(H2O) with increasing average χHCl was correlated with (a) the evaporation range rb∕e parameter, that is, the ratio of Jev(H2O) just before HCl doping of the pure ice film and Jev(H2O) after observable HCl desorption towards the end of film evaporation, and (b) the remaining thickness dD below which Jev(H2O) decreases to less than 85 % of pure ice. The dependence of Jev(H2O) with increasing average χHCl from HCl-doped ice films suggests two limiting data sets, one associated with the occurrence of a two-phase pure ice/crystalline HCl hydrate binary phase (set A) and the other with a single-phase amorphous HCl∕H2O binary mixture (set B). The measured values of Jev(H2O) may lead to significant evaporative lifetime extensions of HCl-contaminated ice cloud particles under atmospheric conditions, regardless of whether the structure corresponds to an amorphous or crystalline state of the HCl∕H2O aggregate.

Fluor‑carbonated hydroxyapatite coatings by pulsed laser deposition to promote cell viability and antibacterial properties

Fluorine, an essential element present in bone and dental tissues, promotes mineralization and is directly involved in the bone formation process. The antibacterial effects of fluorine on oral bacteria are also well known. In this study, metallic implants were coated with a thin layer of calcium phosphate enriched with fluorine to improve osteointegration and protect against infections. These coatings were obtained by pulsed laser deposition (PLD) using, as a target, a bioceramic of marine origin, mainly composed of fluorapatite from the enameloid of shark teeth. The compositional dependence of coatings on H2O vapor pressures applied during PLD was analyzed in order to optimize physicochemical properties. Physicochemical characterization to evaluate morphology (SEM), thickness (interferometric profilometry), structure (XRD) and composition (FTIR, XPS) was performed. To evaluate the biological response, both MC3T3-E1 pre-osteoblasts and bacterial strains Staphylococcus aureus and Staphylococcus epidermidis, most responsible for 77% of infections associated with prosthetic implants, were tested. Proper cell proliferation (MTT assay) and ALP synthesis up to 21 days were confirmed. Antibacterial properties were also demonstrated: compared to synthetic hydroxyapatite coatings, there was a significant reduction in colony-forming units (CFUs) for both strains.

Evaluation of Water Activity in H2O–PEG400–PEG6000 Solutions between 318.15 and 348.15 K

The vapor pressure of H2O(1)-polyethylene glycol 400(2)-polyethylene glycol 6000(3) solutions was evaluated experimentally in a temperature range between 318.15 and 348.15 K and in a broad range of concentrations. The dependence of the solvent activity on composition was evaluated and correlated by means of a polynomial expression, in terms of concentrations, volumetric and mass fractions, and temperature, obtaining in all cases standard deviations less than 0.0086 and 0.0106 for a1(ϕ2,ϕ3,T) and a1(w2,w3,T), respectively.

The structural impact of water sorption on device-quality melanin thin films.

The melanins are a class of pigmentary bio-macromolecules ubiquitous in the biosphere. They possess an intriguing set of physico-chemical properties and have been shown to exhibit hybrid protonic-electronic electrical conductivity, a feature derived from a process termed chemical self-doping driven by the sorption of water. Although the mechanism underlying the electrical conduction has been established, how the sorbed water interacts with the melanin structure at the physical level has not. Herein we use neutron reflectometry to study changes in the structure of synthetic melanin thin films as a function of H2O and D2O vapour pressure. Water is found to be taken up evenly throughout the films, and by employing the contrast effect, the existence of labile protons through reversible deuterium exchange is demonstrated. Finally, we determine a sorption isotherm to enable quantification of the melanin-water interactions.

Persistent Water-Nitric Acid Condensate with Saturation Water Vapor Pressure Greater than That of Hexagonal Ice.

A laboratory chilled mirror hygrometer (CMH), exposed to an airstream containing water vapor (H2O) and nitric acid (HNO3), has been used to demonstrate the existence of a persistent water-nitric acid condensate that has a saturation H2O vapor pressure greater than that of hexagonal ice (Ih). The condensate was routinely formed on the mirror by removing HNO3 from the airstream following the formation of an initial condensate on the mirror that resembled nitric acid trihydrate (NAT). Typical conditions for the formation of the persistent condensate were a H2O mixing ratio greater than 18 ppm, pressure of 128 hPa, and mirror temperature between 202 and 216 K. In steady-state operation, a CMH maintains a condensate of constant optical diffusivity on a mirror through control of only the mirror temperature. Maintaining the persistent condensate on the mirror required that the mirror temperature be below the H2O saturation temperature with respect to Ih by as much as 3 K, corresponding to up to 63% H2O supersaturation with respect to Ih. The condensate was observed to persist in steady state for up to 16 h. Compositional analysis of the condensate confirmed the co-condensation of H2O and HNO3 and thereby strongly supports the conclusion that the Ih supersaturation is due to residual HNO3 in the condensate. Although the exact structure or stoichiometry of the condensate could not be determined, other known stable phases of HNO3 and H2O are excluded as possible condensates. This persistent condensate, if it also forms in the upper tropical troposphere, might explain some of the high Ih supersaturations in cirrus and contrails that have been reported in the tropical tropopause region.

Preparation of organic–inorganic hybrid zeolites with highly-conserved framework carbon by an improved DGC route

Methylene-bridged mordenite zeolite with highly-conserved framework carbon is successfully prepared by an improved DGC route for the first time, which is facile, controllable, and efficient. By the improved DGC method, the C content reserved in the framework of the hybrid materials is calculated to be from 88.4 to 99.2 wt%, much higher than those synthesized by conventional hydrothermal (<32 wt%) and conventional DGC (<59 wt%) methods, indicating that only a little amount of Si–CH2–Si linkage cleaved during the crystallization under relative low H2O vapour pressure. Compared with the conventional DGC route and hydrothermal synthesis method, the improved DGC route has obvious advantages, inclusive of highly-conserved organic framework carbon, highly-efficient usage of autoclaves, highly-efficient usage of chemical sources, saving of energy and low pressure. Moreover, the high competitive adsorptivity for organics and water over the hybrid materials is studied. The new crystallization methodology is instructive for the preparation and application of other organic–inorganic hybrid zeolite analogues.

SEM studies of vacuum condition influence on thermally induced Au self-organization on Ge(001) surface

Vacuum condition influence on the thermally induced self-organization of thin film of 6 monolayers (ML) of Au on atomically flat Ge(001) surface was studied by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) techniques. Metallic islands, up to 100nm in size, were found on samples annealed at Ultra High Vacuum (UHV) conditions just after Au deposition. Annealing of air exposed samples resulted in the formation of big islands, up to 400nm in size together with small ones, 10nm in size. In opposite, samples annealed at 3mbar of H2O vapour pressure were found to have surface etched into the inverted pyramid pits formed around Au clusters. The size of the etched pits is proportional to the size of Au clusters.

Scanning electron microscopy cathodoluminescence of quartz: Principles, techniques and applications in ore geology

Scanning electron microscopy cathodoluminescence (SEM-CL) of quartz has been a prevalent research technique in porphyry and epithermal systems for the past two decades. Quartz from specific geological environments reveals unique textures in SEM-CL, which can be used to constrain the evolution of these ore-bearing systems when complemented by fluid inclusion, hyperspectral mapping, and trace element studies. We review SEM-CL principles and instrumentation, sample preparation and handling, and experimental conditions of quartz SEM-CL imaging that result in the high quality CL images. The effects of sample polishing, accelerating voltage, beam spot size, working distance, vacuum conditions, image acquisition, and post-processing were examined through experimental trial. For the XL 30 ESEM and the attached Gatan PanaCL detector used, the optimum experimental conditions to obtain high quality panochromatic SEM-CL images of quartz at high vacuum mode for carbon-coated conductive samples are as follows: 15kV accelerating voltage, relative beam spot size 6 (approximately 500nm in diameter), HT −570V to −580V photomultiplier tube (PMT) voltage. Low vacuum mode (with chamber H2O vapor pressure from 0.1 to 1.0Torr) working conditions are similar to the conditions at high vacuum mode except the PMT voltage should be reduced to −550V to −560V. Working distances vary based on the position of user's retractable CL detector. The sample surface should be as close as possible to the CL detector, but a 1mm clearance between the detector and the sample surface is recommended to prevent detector from possible damage by the sample. Several minutes of beam exposure prior to image acquisition at 320second scan speeds at 50×–1500× magnifications is recommended to generate the greatest CL emission. Monochromatic CL imaging requires three scans over the same area using red, green, and blue optical filters that can be merged to produce a “true color” image. The red and green filters require stronger PMT voltages to produce sufficient CL emissions by an increase of −200V to −300V and −150V to −200V, respectively, from the PMT voltage used for panochromatic imaging. Special attention is given to the challenges associated with imaging hydrothermal quartz veining in ore deposits and the value of CL data as a foundation for geochemical studies. SEM-CL imaging of vein quartz is explored through case studies of the Red Hills Porphyry Cu–Mo Deposit, Texas, USA, and the Ertsberg–Grasberg Cu–Au District, Papua, Indonesia to aid in vein paragenesis. The most common application of quartz SEM-CL in ore geology is to reveal the relative timing of mineral precipitation, mineral dissolution, and inherited structural features. Understanding of temporal relations among these events makes it possible to select specific generations of quartz within a vein for further studies such as the TitaniQ thermometry and fluid inclusion microthermometry in order to establish T–P–X fluctuations throughout the development of a hydrothermal system.

Determination of thermodynamic stability of lanthanum chloride hydrates (LaCl3⋅xH2O) by dynamic transpiration method

The decomposition pattern of LaCl3⋅7H2O(s) was studied by thermogravimetric technique. Thermal decomposition of LaCl3⋅7H2O(s) proceeded through the formation of LaCl3⋅3H2O(s), LaCl3⋅H2O(s) and LaCl3(s) in the temperature range 313 to 413K. Thermodynamic stability of the LaCl3⋅7H2O(s) and its intermediate products were determined by measuring the vapor pressure of water over the compounds employing dynamic transpiration technique. Two independent sets of experiments were carried out to measure the vapor pressure of each step. The average vapor pressure of H2O(g) over LaCl3⋅7H2O(s), LaCl3⋅3H2O(s) and LaCl3⋅H2O(s) could be expressed by the relations: lnpH2O/atm (±0.02)=−7422 (±211)/T+17.5 (±0.6) (327⩽T/K⩽334), lnpH2O/atm (±0.02)=−8287(±566)/T+17.5 (±1.5) (365⩽T/K⩽369) and lnpH2O/atm (±0.01)=−8566(±346)/T+16.4(±1) (391<T/K<396). The standard molar Gibbs energy of formation of LaCl3⋅7H2O(s), LaCl3⋅3H2O(s) and LaCl3⋅H2O(s) derived from the vapor pressure data are found to be: ΔfG°(LaCl3⋅7H2O,s)=−3226 (±13)+1.6(±0.1)T (327⩽T/K<334), ΔfG°(LaCl3⋅3H2O,s)=−2006(±11)+0.8(±0.1)T (365⩽T/K⩽369) and ΔfG°(LaCl3⋅H2O,s)=−1383(±10)+0.4(±0.01)⋅T (391<T/K<396), kJmol−1, respectively.

Effects of vapor pressure on thermodynamic equilibrium in multiphase flow for thermochemical hydrogen production

This paper examines the effects of H2O vapor pressure on the equilibrium conditions of a CuCl2 hydrolysis reactor in the thermochemical Cu–Cl cycle of hydrogen production. A new predictive model is developed to determine the minimum steam requirement in the reactor based on the chemical equilibrium condition, reactor pressure and fraction of gaseous reactant. Experimental data, at three separate vapour pressures of steam, compared well with the new predictive formulation.

Relation between water adsorption in polymer-electrolyte fuel cell and its electric power

The amount of H2O adsorbed on a Nafion® 117 membrane mounted inside a polymer-electrolyte fuel cell (PEFC) system is determined as a function of temperature and H2O vapor pressure. Its experimental values are related with a product of electric current and terminal voltage when the anode and cathode compartments are supplied with partially moist (0% to 90% in relative humidity) H2 and O2 gases at atmospheric pressure, respectively. Under conditions of H2O vapor pressure lower than 2×104Pa, the amount of H2O adsorbed on the membrane mounted inside the PEFC module is near to its original one that was determined under an unfixed force-free condition, where it is not mounted in cell. However, under conditions of H2O vapor pressure higher than 2×104Pa, the adsorption amount under the mounted state becomes smaller than its original value determined under the unfixed force-free state. At the higher vapor pressure, the electric power generated under the mounted state also becomes lower than its value expected from the adsorption amount under the unfixed state. Thus, it is experimentally clarified that the FC power is deeply related with the amount of H2O adsorbed on the membrane. The H2O adsorption amount depends on whether it is compressed in a FC by an outside mold or not.

Organic ion yield enhancement in secondary ion mass spectrometry using water vapour injection

The effects of water (H2O) and deuterated water (D2O) vapour, injected closely to the analyzed surface at relatively high pressure, on the enhancement of the ion yield in secondary ion mass spectrometry (SIMS) was investigated for a set of organic samples. The results show that the same signal enhancements occurred either upon Ga+ or C60+ bombardment. In addition, the increase of H2O vapour pressure during the bombardment causes a specific enhancement of the protonated ion intensity. For instance, the presence of H2O vapour induces an enhancement by one order of magnitude of the [M + H]+ static SIMS intensity for the antioxidant Irgafos 168 and by more than two times for the amino acids. Copyright © 2012 John Wiley &amp; Sons, Ltd.