Fourier Transform Infrared Photoacoustic Spectroscopy Research Articles

Application of fourier transform infrared photoacoustic spectroscopy for quantification of nutrient contents and their plant availability in manure and digestate

In this study, we assess the feasibility of using Fourier Transform Infrared Photoacoustic Spectroscopy (FTIR-PAS) to predict macro- and micro-nutrients in a diverse set of manures and digestates. Furthermore, the prediction capabilities of FTIR-PAS were assessed using a novel error tolerance-based interval method in view of the accuracy required for application in agricultural practices. Partial Least-Squares Regression (PLSR) was used to correlate the FTIR-PAS spectra with nutrient contents. The prediction results were then assessed with conventional assessment methods (root mean square error (RMSE), coefficient of determination R2, and the ratio of prediction to deviation (RPD)). The results show the potential of FTIR-PAS to be used as a rapid analysis technique, with promising prediction results (R2 > 0.91 and RPD >2.5) for all elements except for bicarbonate-extractable P, K, and NH4+-N (0.8 < R2 < 0.9 and 2 < RPD <2.5). The results for nitrogen and phosphorus were further evaluated using the proposed error tolerance-based interval method. The probability of prediction for nitrogen within the allowed limit is calculated to be 94.6 % and for phosphorus 83.8 %. The proposed error tolerance-based interval method provides a better measure to decide if the FTIR-PAS in its current state could be used to meet the required accuracy in agriculture for the quantification of nutrient content in manure and digestate.

Selective Removal of Chlorophyll and Isolation of Lutein from Plant Extracts Using Magnetic Solid Phase Extraction with Iron Oxide Nanoparticles.

In recent years, there has been a growing interest in plant pigments as readily available nutraceuticals. Photosynthetic pigments, specifically chlorophylls and carotenoids, renowned for their non-toxic antioxidant properties, are increasingly finding applications beyond their health-promoting attributes. Consequently, there is an ongoing need for cost-effective methods of isolation. This study employs a co-precipitation method to synthesize magnetic iron oxide nanoparticles. Scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS) confirms that an aqueous environment and oxidizing conditions yield nanosized iron oxide with particle sizes ranging from 80 to 140 nm. X-ray photoelectron spectroscopy (XPS) spectra indicate the presence of hydrous iron oxide FeO(OH) on the surface of the nanosized iron oxide. The Brunauer-Emmett-Teller (BET) surface area of obtained nanomaterial was 151.4 m2 g-1, with total pore volumes of pores 0.25 cm3 g-1 STP. The material, designated as iron oxide nanoparticles (IONPs), serves as an adsorbent for magnetic solid phase extraction (MSPE) and isolation of photosynthetic pigments (chlorophyll a, lutein) from extracts of higher green plants (Mentha piperita L., Urtica dioica L.). Sorption of chlorophyll a onto the nanoparticles is confirmed using UV-vis spectroscopy, Fourier transform infrared photoacoustic spectroscopy (FT-IR/PAS), and high-performance liquid chromatography (HPLC). Selective sorption of chlorophyll a requires a minimum of 3 g of IONPs per 12 mg of chlorophyll a, with acetone as the solvent, and is dependent on a storage time of 48 h. Extended contact time of IONPs with the acetone extract, i.e., 72 h, ensures the elimination of remaining components except lutein, with a spectral purity of 98%, recovered with over 90% efficiency. The mechanism of chlorophyll removal using IONPs relies on the interaction of the pigment's carbonyl (C=O) groups with the adsorbent surface hydroxyl (-OH) groups. Based on molecular dynamics (MD) simulations, it has been proven that the selective adsorption of pigments is also influenced by more favorable dispersion interactions between acetone and chlorophyll in comparison with other solutes. An aqueous environment significantly promotes the removal of pigments; however, it results in a complete loss of selectivity.

Copaiba Oil-Based Emulsion as a Natural Chemotherapeutic Agent for the Treatment of Bovine Mastitis: In Vivo Studies

Copaiba oil-resin (COR) extracted from Copaifera reticulata Ducke has been used as a natural chemotherapeutic agent for a wide range of therapeutic applications. This study presents an emulgel design with a high concentration of COR, designed to prevent and treat mastitis. The COR was stabilized in a gel matrix constituted by carbopol C934P and Pluronic® F127 (ECO formulation) ratios. The permeation study of ECO was accessed by Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS). The results reveal a high capacity of ECO to permeate deep skin layers. Dairy cows with a history of mastitis were used as in vivo models and exposed to ECO treatment. Monitoring of the teat's inflammatory response showed that ECO effectively prevents mastitis. Furthermore, the ECO formulation was able to form a thin film gel on the application side, preventing fly proliferation and significantly reducing the pathogen load. This study reveals a drug that can used as an alternative application for mastitis in human or veterinary clinics.

Ex vivo UV-vis and FTIR photoacoustic spectroscopy of natural nanoemulsions from cellulose nanocrystals and saponins topically applied into the skin: Diffusion rates and physicochemical evaluation.

Nanoemulsions are increasingly gaining importance in the development of topically applied medicine and cosmetic products because their small droplets favor the penetration rates of active compounds into the body. In this scenario, the measurements of their diffusion rates as well as eventual physicochemical changes in the target tissues are of utmost importance. It is also recognized that the use of natural surfactants can avoid allergic reactions as frequently observed for synthetic products. The natural saponins extracted from Sapindus Saponaria have the property of forming foam and are exploited as biocompatible and biodegradable, while cellulose nanocrystals are known to increase the stability of a formulation avoiding the coalescence of drops at the interface. Therefore, nanoemulsions combining natural saponins and cellulose nanocrystals are promising systems that may facilitate greater diffusion rates of molecules into the skin, being candidates to substitute synthetic formulations. This study applied the Photoacoustic Spectroscopy technique to measure the diffusion rates and the physicochemical properties of nanoemulsified formulations containing saponins and cellulose nanocrystals topically applied to the skin. The ex vivo study combined the first-time photoacoustic measurements performed in both ultraviolet-visible and mid-infrared spectral regions. The toxicity of these formulations in L929 cells was also evaluated. The results showed that the formulations were able to propagate throughout the skin to a depth of approximately 756μm, reaching the dermal side. The non-observation of absorbing band shifting or new bands in the FTIR spectra suggests that there were no structural changes in the skin as well as in the formulations after the nanoemulsions administration. The cytotoxicity results showed that the increase of cellulose nanocrystals concentration decreased cellular toxicity. In conclusion, the results demonstrated the advantage of combining photoacoustic methods in the ultraviolet-visible and mid-infrared spectral regions to analyze drug diffusion and interaction with the skin tissues. Both methods complement each other, allowing the confirmation of the nanoemulsion diffusion through the skin and also suggesting there were no detectable physicochemical changes in the tissues. Formulations stabilized with saponins and cellulose nanocrystals showed great potential for the development of topically administered cosmetics and drugs.

Non-destructive assessment of milk quality using pulsed UV photoacoustic, fluorescence and near FTIR spectroscopy

The work describes the application of photoacoustic (PA), fluorescence spectroscopy, and Fourier transform near-infrared spectroscopy as non-destructive optical techniques to examine the quality of milk. The amplitude of the acoustic wave was linearly proportional to the absorbed fluence. The acoustic velocity and the fluence threshold for onset of non-linearity were decreased as the fat % increased. Initially, the PA pressure was increased with fluence but it exhibited non-linearity and occurred earlier i.e. faster as the fat % was increased. The peak pressures of 120, 160, and 180 kPa were determined for 1%, 2%, and 3.5% respectively. The corresponding acoustic transient times of 0.5, 0.44, and 0.36 µs were calculated for 1%, 2%, and 3.5% milk respectively. The absorption coefficient of milk samples was determined using the pressure-fluence slope and Grüneisen constant, which increased with fat %. The bandwidths between 350–450 nm and 450–550 nm correspond to tryptophan or valine, and Methionine amino acids respectively, and the peak at ≈315 nm is thought to be due to tyrosine. The fluorescence intensity of the sample day 1 (D1-open) decreased with time more significantly due to variations in the environmental condition. The bands between 4000 and 4500 cm−1 correspond to CH-stretch, and day 4 (D4-closed) showed the highest peak amplitudes compared to the others. Combination of N–H and O–H stretch was mainly observed between 4500 and 5000 cm−1, and the bands at 4581, 4655 cm−1 in fresh sample disappeared in D1-open and D1-closed. New bands of 4717, 4792, and 4829 cm−1 were observed.

FTIR Photoacoustic and ATR Spectroscopies of Soils with Aggregate Size Fractionation by Dry Sieving.

Granulometric fractionation as a source of additional information on organic-matter and inorganic matrix components of soils using FTIR–photoacoustic spectroscopy (FTIR–PAS) supported by attenuated–total reflection FTIR spectroscopy (ATR–FTIR) for a wide range of aggregate fractions (10–5000 μm) was used to compare the sensitivity, reproducibility, information contents, and representativity of fractionated samples. For chernozem and sod-podzolic soils and different agricultural-use chernozem samples, differences in the composition were found, manifested in normalized spectra of microaggregate fractions, with the range of 10–100 μm bearing the complete information. Most changes are observed in the soil organic matter range (1900–1340 cm–1), although these changes are slight, and in the soil-matrix region (550–300 cm–1). The latter region increases the intensity of bands corresponding to amorphous silica and clay minerals in fine fractions, while the intensity of bands attributed to quartz lattice vibrations decreases. FTIR–PAS spectra do not differ considerably at high interferometer modulation frequencies as the signal-penetration depth is comparable with particle sizes. The soil fractions below 20 μm result in the maximum sensitivity, reproducibility, and signal-to-noise ratio, showing no changes from coarser fractions by the information content and, thus, providing representative samples for analysis. The fractionation shows more differences in the sod-podzolic and chernozem soil fractions than the whole soil spectra. FTIR–PAS provides better sensitivity and reproducibility in the 4000–2000 cm–1 region and ATR–FTIR in the 2000–100 cm–1 region.

A method for bivalve shells characterization by FT-IR photoacoustic spectroscopy as a tool for environmental studies

Fourier Transform Infrared Spectroscopy has been employed to investigate the composition of the shells of two marine bivalves Mytilus galloprovincialis and Corbula gibba from four samples collected from the Mar Piccolo of Taranto (Ionian Sea, Southern Italy). Bivalve shells are composed of 95–99.9% calcium carbonate (CaCO3), while the remaining portion is constituted by organic matrix, which in some cases may incorporate pollutants from the surrounding environment. Recognizing the role of bivalves in the carbon biogeochemical cycle and their economic importance for aquaculture, we aimed to develop a methodology for shells powder samples preparation and analysis. The main objective of the study was to demonstrate the feasibility of Fourier Transform Infrared photoacoustic spectroscopy to perform a fast sample analysis in order to detect the possible presence of pollutants in the shells.The results revealed an unbiased differentiation between the shell compositions of the two bivalve selected species. Moreover, the spectra interpretation indicated that C. gibba specimens recorded a shell matrix contaminated by organic pollutants present in the surrounding environment. In conclusion, the described methodology including sample preparation tailored for photoacoustical investigations demonstrated to be a tool for the characterization of bivalve shells contamination enhancing environmental studies of polluted marine areas.•Bivalve species were collected from sampling stations located in the Mar Piccolo of Taranto (Ionian Sea, Southern Italy).•Samples preparation stages include: sonication, grinding and fractioning by sieving.•FT-IR PAS spectral region of interest is in the mid-infrared between 4000 and 400 cm−1.

Application of Ftir-Photoacoustic Spectroscopy for Rapid Assessment of Phosphorus Availability in Digestates and Digestate-Amended Soils

Application of Ftir-Photoacoustic Spectroscopy for Rapid Assessment of Phosphorus Availability in Digestates and Digestate-Amended Soils

Mature Landfill Leachate as a Medium for Hydrodynamic Cavitation of Brewery Spent Grain

In this study, we evaluate the usefulness of mature landfill leachate (MLL) as a carrier allowing hydrodynamic cavitation (HD) of brewery spent grain (BSG). The HD experiments were conducted using an orifice plate with a conical concentric hole of 3/10 mm (inlet/outlet diameter) as a constriction in the cavitation device. The initial pressure was 7 bar and the number of recirculation passes through the cavitation zone reached 30. The results showed that complex organic matter was degraded and solubilized when cavitating the MLL and BSG mixture. The biochemical oxygen demand (BOD5) increased by 45% and the BOD5/total chemical oxygen demand (COD) ratio increased by 69%, whereas the COD, total solids, and nutrient concentration dropped noticeably. However, Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) revealed the generation of possibly toxic HD byproducts such as aromatic compounds. This seems to indicate that MLL could not be regarded as a suitable carrier for BSG cavitation.

Application of FTIR-PAS in Rapid Assessment of Rice Quality under Climate Change Conditions.

Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS), versus attenuated total reflectance spectroscopy (FTIR-ATR) and diffuse reflectance spectroscopy (DRIFT), was firstly applied in quick assessment of rice quality in response to rising CO2/temperature instead of conventional time-consuming chemical methods. The influences of elevated CO2 and higher temperature were identified using FTIR-PAS spectra by principal component analysis (PCA). Variations in the rice functional groups are crucial indicators for rice identification, and the ratio of the intensities of two selected spectral bands was used for correlation analysis with starch, protein, and lipid content, and the ratios all showed a positive linear correlation (R2 = 0.9103, R2 = 0.9580, and R2 = 0.9246, respectively). Subsequently, changes in nutritional components under future environmental conditions that encompass higher CO2 and temperature were evaluated, which demonstrated the potential of FTIR-PAS to detect the responses of rice to climate change, providing a valuable technique for agricultural production and food security.

Effect of Weathering on Surface Functional Groups of Charred Norway Spruce Cladding Panels

Norway spruce cladding panels were surface charred with a prototype device utilizing a hot plate method. The panels were used to construct a test wall that was exposed to natural weathering for a period of two years. The changes in functional groups were evaluated with photoacoustic FTIR spectroscopy. The analysis revealed degradation of the thermally modified lignin component, indicating poor stability in weathering. Improvements in the prototype device process conditions, such as increased surface pressure and slower feed speed, and future research needs regarding surface charred wood are discussed.

Tailoring surface properties of carbon nanofibers via oxidation and its influence on dental pulp stem cell viability of PCL/CNF composites

The effect of oxidation time on the surface chemical and morphological properties of carbon nanofibers (CNFs) and their suitability for use as a reinforcement agent in the development of bone scaffolds was assessed. The CNFs were modified using a 3:1 v/v mixture of concentrated sulfuric (H2SO4) and nitric acid (HNO3) for different periods of time. Several analytical techniques were used to characterize the oxidized CNF surface properties. Photoacoustic Fourier transform infrared spectroscopy (PAS-FTIR) showed the creation of carboxylic groups due to the acid treatments. Scanning electron microscopy images revealed differences in the nanofibers before and after acid treatment. The relationship between the CNF crystals and their defects when varying the oxidation time were determined by Raman spectroscopy. The CNF FTIR results, contact angle measurements, and dispersion tests showed the formation of carboxylic groups due to the oxidative treatment. The results confirmed the presence of microstructures with defects, as well as chemically active functional surface groups, such as carboxyls and hydroxyls. Furthermore, a composite was prepared using polycaprolactone (PCL) as a matrix and the CNF as the reinforcement. The storage module of the oxidized CNFs was improved with respect to the nonoxidized CNFs. Furthermore, the scaffolds of PCL with oxidized CNFs enhanced the cell proliferation.

FTIR photoacoustic spectroscopy for identification and assessment of soil components: Chernozems and their size fractions

FTIR photoacoustic spectroscopy was used to approach inorganic matrix components and organic-matter constituents of chernozem size fractions (1–5000 μm, by dry sieving) with a different history of use (from intact steppe to permanent bare fallow, a continuous long-term field experiment). The conditions of FTIR photoacoustic measurements in continuous-scan modes were compared with attenuated total reflection measurements, the advantages of photoacoustic measurements resulting from a higher intensity of the incident radiation and signal-generating volume were discussed. Overtone peaks of quartz as a soil matrix component at 2000–1700 cm–1 were selected as a possible internal-standard (guide) bands for the comparison of photoacoustic spectra. For different land-use samples, differences in the composition were found, which are differently manifested in normalized spectra of size fractions, with millimeter-size, 20–100 μm, and silt fraction bearing the maximum information.

Responses of Leaf Cuticles to Rice Blast: Detection and Identification Using Depth-Profiling Fourier Transform Mid-Infrared Photoacoustic Spectroscopy.

Cuticle is the first barrier for rice to resist blast fungus on the surface of the leaf. Studies on how the rice leaf cuticle responds to rice blast and attempts to perform early detection of rice blast are limited, and these two issues were explored in this study via depth-profiling Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS). Rice leaves with four different scales of injury (healthy leaves as CK, asymptomatic leaves from mildly diseased seedlings as S1, infected leaves with fewer than five lesions as S2, and infected leaves with more than 10 lesions as S3) were scanned by three moving mirror velocities 0.32, 0.47, and 0.63 cm/s for the depth profiling of the rice leaf surface. The response patterns were acquired via chemometrics to analyze the variations of the chemical group absorptions in the different layers of a sample and in the same layer between different samples. Results showed that the leaf cuticle tended to be thicker and the relative content of fatty alcohols and cutin, unsaturated compounds, and aromatics in the cuticle increased when rice seedlings were infected by blast fungus. Together with the principal component analysis, the probabilistic neural network was applied to identify the samples in early stages (CK and S1), which reached an accuracy of 90% for the samples in the greenhouse and 82% for the samples in the field. Thus, depth-profiling FTIR-PAS was good at analyzing the variation in cuticle layers and showed great potential in the early detection of rice blast or other diseases in different species.

Evaluation of Inter and Intraspecific Differences in the Venom Chemical Compositions of Polybia paulista Wasps and Ectatomma brunneum Ants Using FTIR-PAS

Wasps can synthesize chemical compounds called venom whose function is to overcome prey and assist in defense of the colonies. Geographic Parameters such as sex, age, the season of the year, and diet determined the composition of the venom location, genetics, environment. However, studies on the compositional variability of venom are still limited due to the difficulty in obtaining samples and the complexity of these substances. This work describes the use of the Fourier Transform Infrared Photoacoustic Spectroscopy (FTIR-PAS) to investigate inter- and intraspecific variability in the venom chemical composition (VCC) of the social wasp Polybia paulista (Von Ihering 1896) and the ant Ectatomma brunneum (Smith 1858). The results reveal significant differences in VCC among the ant and wasp, even for samples obtained from the same environment. The genetic component, therefore, seemed to be the predominant factor determining the compounds present. The findings also showed that exogenous factors, such as diet, could also be responsible for intraspecific differences, especially in wasps. The FTIR-PAS technique proved to be a reliable way of assessing intra- and interspecific differences in social Hymenoptera VCC.

In situ detection of rice leaf cuticle responses to nitrogen supplies by depth-profiling Fourier transform photoacoustic spectroscopy

Plant cuticle is an important interface on the outmost region of plant and will make the response to environmental changes. However, research about how the variable nutritional status affect plant cuticle is limited. This was the first report about the manners of rice leaf cuticle in answer to different nutritional circumstances of nitrogen detected by the Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) which with a main superiority for in situ and depth-profiling in mid-infrared range. Rice leaves from the seedlings treated with three nitrogen levels designed as low (22N1), medium (N2) and high (N3) concentration were scanned by three moving mirror velocities (0.32 cm s-1, 0.47 cm s-1, and 0.63 cm s-1) at 900-4000 cm-1 to acquire the spectra of leaf surfaces. Well-resolved peaks had been detected at 3400, 2800, 1650, 1520 and 1050 cm-1. Combining with the structures and compositions of cuticle, the spectra recorded with 0.63 cm s-1 were identified to be from cuticle, and were used to analyze the responses of cuticle. Through curve-fitting, the absorption ratio of the peaks at (cm-1) 1050/3400, 1050/2800 and 1650/2800 shown regular changes，which were suggested to corresponded with ν(CO)/ν(OH), ν(CO)/ν(CH) and ν(C=C)/ν(CH) mainly. These ratios were supported to reflect the amount or variation of cuticle components, such as cutin, fatty alcohols, acids and unsaturated compounds. It provided insights about how nitrogen affected cuticles and showed great potentials to utilized FTIR-PAS for detecting cuticle variations.

Intraspecific Cuticular Chemical Profile Variation in the Social Wasp Mischocyttarus consimilis (Hymenoptera, Vespidae).

Chemical compounds present on the cuticle of social insects are important in communication, as they are used in recognition of nestmates and sexual partners as well as in caste distinction, varying according to several factors, such as genetic and environmental. In this context, some studies have explored the cuticular chemical profile as a tool for assessing intra- and interspecific differences in social insects, although few studies have investigated this in social wasps. This study aimed to assess the differences in cuticular chemical profiles among different geographic samples of the wasp Mischocyttarus consimilis Zikán. Our hypothesis was that environmental factors are decisive to compose the cuticular chemical profiles of colonies of these social wasps and that there are differences regarding the geographic distribution among colonies. We used Fourier Transform Infrared-Photoacoustic Spectroscopy (FTIR-PAS) to assess the chemical profiles of samples. Our results show that despite there are differences between the cuticular chemical composition of the wasps' samples from different populations, there is no significant correlation compared to the spatial distribution of the colonies nor with the environment. Thus, our hypothesis was refuted, and we can infer that in this species neither exogenous nor genetic factors stand out to differentiate the chemical signature of their colonies, but a combination of both.

Rapid diagnosis of nitrogen status in rice based on Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS)

BackgroundAn effective and expeditious approach to assess plant nitrogen status is urgently needed in rice production and management as the conventional chemical methods are laborious and time-consuming.ResultsFourier transform infrared photoacoustic spectroscopy (FTIR-PAS) was used to record the spectra of rice leaves for the effective diagnosis of nitrogen nutrition status. The band in the wavenumber range of 1680 to 1630 cm−1 was associated with amide I and that from 1570 to 1510 cm−1 with amide II. We attempted to use this information to characterize the nitrogen status in rice plants at different growth stages. The ratio of photoacoustic intensity of amide II to amide I was measured and applied as nitrogen status index, and considering the yields, the ratio showed a positive linear correlation (R2 = 0.9) with the total nitrogen of rice leaves. The ratio at the tillering and full panicle stages were more suitable for diagnosis, a ratio of 0.4–0.55 indicated an adequate nitrogen status, ratios lower than 0.4 indicated a poor nitrogen status; whereas ratios greater than 0.55 indicated excessive nitrogen supply.ConclusionOur study provides an effective and rapid strategy for nitrogen-supply assessment in rice based on FTIR-PAS, which can guide rational fertilization in rice production.

Photoacoustic infrared spectroscopic studies of silica surface functionalized by dendrimers

Fourier Transform Infrared Photoacoustic Spectroscopy (FT-IR/PAS) is one of the types of classic Infrared Spectroscopy (IR), which is based on recording the pressure changes in a measuring cell, caused by vibrations of particular bonds, triggered by periodically changed wavelengths of infrared radiation. The main advantages offered by FT-IR/PAS technique are the possibility of characterization of non-homogenous or opaque materials and no need of samples dilution.The following article is concerned with characterization of a series of silica-based hybrid materials grafted with dendritic structures, by FT-IR/PAS measurements. The study involved immobilization of poly(amidoamine) (PAMAM) and poly(hydroxyl) (bis-MPA-OH) dendrimers on silica platform with either isocyanate or maleimide surface functional groups. It was expected that the loading of dendritic structures on silica platforms was relatively low, however, the recorded spectra showed distinct and measurable signals originating from each bonding type. Unless the signals had overlapped each other, the distinguished bands were assigned to several functional groups, which confirmed successful anchoring of dendritic structures on silica matrices.

How does aquatic macrophyte Salvinia auriculata respond to nanoceria upon an increased CO2 source? A Fourier transform-infrared photoacoustic spectroscopy and chlorophyll a fluorescence study

With the continued increase of technological uses of cerium oxide nanoparticles (CeO2 NPs or nanoceria) and their unregulated disposal, the accumulation of nanoceria in the environment is inevitable. Concomitantly, atmospheric carbon dioxide (CO2) levels continue to rise, increasing the concentrations of bicarbonate ions in aquatic ecosystems. This study investigates the influence of CeO2 NPs (from 0 to 100 μgL−1) in the presence and absence of an elevated bicarbonate (HCO3−) ion concentration (1 mM), on vibrational biochemical parameters and photosystem II (PSII) activity in leaf discs of Salvinia auriculata. Fourier transform-infrared photoacoustic spectroscopy (FTIR-PAS) was capable of diagnostic use to understand biochemical and metabolic changes in leaves submitted to the CeO2 NPs and also detected interactive responses between CeO2 NPs and HCO3− exposure at the tissue level. The results showed that the higher CeO2 NPs levels in the presence of HCO3− increased the non-photochemical quenching (NPQ) and coefficient of photochemical quenching in dark (qPd) compared to the absence of HCO3. Moreover, the presence of HCO3− significantly decreased the NPQ at all levels of CeO2 NPs demonstrating that HCO3− exposure may change the non-radiative process involved in the operation of the photosynthetic apparatus. Overall, the results of this study are useful for providing baseline information on the interactive effects of CeO2 NPs and elevated HCO3− ion concentration on photosynthetic systems.