Different Types Of Instruments Research Articles

Instrumental variables estimation: Assumptions, pitfalls, and guidelines

Researchers striving to ensure rigor in their scientific findings face a common pitfall: Endogeneity. To tackle this problem, scholars have increasingly adopted instrumental variables estimation (IVE). Although there are many published works showing how IVE should be used, many applied researchers still have trouble understanding how to use the method correctly. In this article, we provide a methodological overview of IVE by discussing the underlying conditions valid instruments must satisfy as well as common mistakes made in using IVE. Using simulated data, we further demonstrate the sensitivity of IVE to violations of its conditions. We then take stock of the literature in a social science discipline (i.e., leadership research) and provide insights regarding trends and shortcomings in the application of IVE. Based on our review, we categorize the different types of instruments used and discuss the potential appropriateness of each type. We conclude by providing non–technical guidelines targeted at the study design, analysis, and reporting phases, which will help applied social science researchers to ensure they use IVE correctly.

Mathematical Processing of Experimental Data Obtained with Ampoule and Titration Calorimeters Equipped with Different Types of Cells

An algorithm is described for calculating the equilibrium constants and changes in the enthalpy of chemical reactions according to data from a calorimetric experiment performed on instruments of different types. Freeware is developed that executes the described algorithm. Differences from existing computer programs with similar functionality are briefly discussed, along with different statistical criteria of maximum likelihood.

Improved Principal Component Analysis (IPCA): A Novel Method for Quantitative Calibration Transfer between Different Near-Infrared Spectrometers.

Given the labor-consuming nature of model establishment, model transfer has become a considerable topic in the study of near-infrared (NIR) spectroscopy. Recently, many new algorithms have been proposed for the model transfer of spectra collected by the same types of instruments under different situations. However, in a practical scenario, we need to deal with model transfer between different types of instruments. To expand model applicability, we must develop a method that could transfer spectra acquired from different types of NIR spectrometers with different wavenumbers or absorbance. Therefore, in our study, we propose a new methodology based on improved principal component analysis (IPCA) for calibration transfer between different types of spectrometers. We adopted three datasets for method evaluation, including public pharmaceutical tablets (dataset 1), corn data (dataset 2), and the spectra of eight batches of samples acquired from the plasma ethanol precipitation process collected by FT-NIR and MicroNIR spectrometers (dataset 3). In the calibration transfer for public datasets, IPCA displayed comparable results with the classical calibration transfer method using piecewise direct standardization (PDS), indicating its obvious ability to transfer spectra collected from the same types of instruments. However, in the calibration transfer for dataset 3, our proposed IPCA method achieved a successful bi-transfer between the spectra acquired from the benchtop and micro-instruments with/without wavelength region selection. Furthermore, our proposed method enabled improvements in prediction ability rather than the degradation of the models built with original micro spectra. Therefore, our proposed method has no limitations on the spectrum for model transfer between different types of NIR instruments, thus allowing a wide application range, which could provide a supporting technology for the practical application of NIR spectroscopy.

Writing apprehension and writing skills on English department students: A correlational design

By two different types of instruments—a questionnaire to determine students' writing apprehension and a writing test using descriptive texts to decide students' writing skills—this study investigated the correlation between writing apprehension and students' writing skills. This study used quantitative correlational research, and the English department served as the study's target population. Additionally, the researchers employed cluster sampling and correlational design, which can choose a representative sample and represent the population. To conduct the analysis, the researchers chose one class as a sample, and thirty-five students from the third semester were chosen as the sample. According to the researchers, writing apprehension and students' writing skills were shown to be negatively correlated, who concluded that the correlation between the two was r = -0.642. The inverse correlation indicates that students did not perform as good as on writing tests the more frequently they worry about writing. Additionally, it can be inferred that there is a strong correlation between students' writing skills and their level of writing apprehension.

Vibrational Music Therapy with D/deaf clients

D/deaf clients perceive music through their bodies. The music therapist needs various methods to appreciate these sensations. It is necessary to examine the instruments from a vibrational perspective. Also, listening to the client is more important than speaking. This article focuses on how non-verbal methods are more appropriate when working with clients who have a hearing loss. Vibrosensoric approach to music combined with touch-based communication methods (social-haptic communication) enhances a positive client response. As a deafblind music therapist, musical vibrations play an important role for me as well as for the client during a therapy process. Background noise and spoken language can sometimes mask the perception of musical tones from different types of instruments. Speech with music within GIM sessions renders the client unable to follow either music or storyline. This distorts the sounds in hearing aid devices. Therefore, the instrument selection within the therapy session needs to be considered from a vibratory aspect. Musical tones from the instruments can be felt in different parts of the body. In this case, the focus is not on how an instrument sounds but more on the vibrational sensations it produces.

The Efficiency of the BTR-Pen System in Removing Different Types of Broken Instruments from Root Canals and Its Effect on the Fracture Resistance of Roots.

The study aimed to evaluate the efficiency of the BTR-Pen system in removing different types of instrument fragments from root canals and to assess its effect on fracture resistance of the roots after the removal of the instruments. One hundred thirty human teeth were divided into 10 groups (2 control groups and 8 study groups) according to the localization and type of the fractured fragment as well as the retrieval techniques. Broken instruments were extracted either with BTR-Pen system loops or removed using solely ultrasonic tips. The success rate of instrument removal and consumed time were recorded. All the teeth were subjected to a load at a 1 mm/min rate in a universal testing machine for mechanical testing. The success of removing broken instruments using the BTR-Pen and ultrasonic was 86.7% and 83.3%, respectively (p > 0.05). When the time is compared, the BTR-Pen system (23.97 ± 8.35 min) showed similar results to that of the ultrasonic technique (24.1 ± 8.28 min) (p > 0.05). The BTR-Pen group required less force to fracture than the ultrasonic group (p = 0.024). In conclusion, the BTR-Pen and ultrasonic groups showed no significant difference in terms of the success rate and removal time. The roots that underwent instrument removal using the BTR-Pen system had less fracture resistance.

Instrument-type effects on chemical isotope labeling LC-MS metabolome analysis: Quadrupole time-of-flight MS vs. Orbitrap MS

Chemical isotope labeling (CIL) LC-MS is a powerful tool for metabolome analysis with markedly improved metabolomic coverage and quantification accuracy over the conventional LC-MS technique. In addition, with differential isotope labeling, each labeled metabolite is detected as a peak pair in the mass spectra, offering the possibility of differentiating true metabolite peaks from the singlet noise or background peaks. In this study, we examined the effects of instrument type on the detectability of true metabolites with a focus on the comparison of quadrupole time-of-flight (QTOF) and Orbitrap mass spectrometers. Using the same ultra-high-performance liquid chromatography setup and optimized running conditions for QTOF and Orbitrap, we compared the total number of peak pairs detected and identified from the two instruments using human urine and serum as the test samples. Many common peak pairs were detected from the two instruments; however, there were a significant number of unique peak pairs detected in each type of instrument. By combining the datasets obtained using QTOF and Orbitrap, the total number of peak pairs detected could be significantly increased. We also examined the effect of mass resolving power on peak pair detection in Orbitrap (60,000 vs. 120,000 resolution). The observed differences in peak pair detectability were much less than those of QTOF vs. Orbitrap. However, the type of peak pairs detected using different resolutions could be somewhat different, offering the possibility of increasing the overall number of peak pairs by combining the two datasets obtained at two different resolutions. The results from this study clearly indicate that instrument type can have a profound effect on metabolite detection in CIL LC-MS. Therefore, comparison of metabolome data generated using different instruments needs to be carefully done. Moreover, future research (e.g., hardware modifications) is warranted to minimize the differences in order to generate more reproducible metabolome data from different types of instruments.

Motion Measurement and Analysis of Different Instruments for Single-Incision Laparoscopic Surgery.

Objective To objectively compare and analyze the range of motion of three types of instruments for single-incision laparoscopic surgery. Material and Methods. Ten experienced participants were recruited. Straight instruments (Group A), straight/articulating instruments (Group B), and precurved instruments (Group C) were used to complete the transferring task through one site in a laparoscopic simulator. Straight instruments via two separate sites (Group D) served as control. The operation time of each group was recorded. Instrument positions were measured by an optical tracking system. The inserted length and pivoting angles were derived via MATLAB. Results There was a significant difference in operation time between groups (D < A < B < C, p < 0.01). The range of motion of instruments was different on instrument types and surgical approaches. A significant difference in the inserted length was found between groups. Instrument conflicts and inadequate triangulation were found in Group A; instrument conflicts were found in Group B; no obvious conflicts and triangulation problems were observed in Group C. The operation in Group C was similar to the operation in Group D but differed on the left/right pivoting angles. Conclusion Different types of instruments have different ranges of motion in single-incision laparoscopic surgery. Working with precurved instruments seems like a compromise to traditional laparoscopic surgery if the transmission property, and shaft curvature of the instruments could be improved. An integrated mechanical platform or robotic system might be the ultimate solution for single-incision laparoscopic surgery to pursue even less trauma.

Biomechanical study of oblique lumbar interbody fusion (OLIF) augmented with different types of instrumentation: a finite element analysis

BackgroundTo explore the biomechanical differences in oblique lumbar interbody fusion (OLIF) augmented by different types of instrumentation.MethodsA three-dimensional nonlinear finite element (FE) model of an intact L3-S1 lumbar spine was built and validated. The intact model was modified to develop five OLIF surgery models (Stand-alone OLIF; OLIF with lateral plate fixation [OLIF + LPF]; OLIF with unilateral pedicle screws fixation [OLIF + UPSF]; OLIF with bilateral pedicle screws fixation [OLIF + BPSF]; OLIF with translaminar facet joint fixation + unilateral pedicle screws fixation [OLIF + TFJF + UPSF]) in which the surgical segment was L4–L5. Under a follower load of 500 N, a 7.5-Nm moment was applied to all lumbar spine models to calculate the range of motion (ROM), equivalent stress peak of fixation instruments (ESPFI), equivalent stress peak of cage (ESPC), equivalent stress peak of cortical endplate (ESPCE), and equivalent stress average value of cancellous bone (ESAVCB).ResultsCompared with the intact model, the ROM of the L4–L5 segment in each OLIF surgery model decreased by > 80%. The ROM values of adjacent segments were not significantly different. The ESPFI, ESPC, and ESPCE values of the OLIF + BPSF model were smaller than those of the other OLIF surgery models. The ESAVCB value of the normal lumbar model was less than the ESAVCB values of all OLIF surgical models. In most postures, the ESPFI, ESPCE, and ESAVCB values of the OLIF + LPF model were the largest. The ESPC was higher in the Stand-alone OLIF model than in the other OLIF models. The stresses of several important components of the OLIF + UPSF and OLIF + TFJF + UPSF models were between those of the OLIF + LPF and OLIF + BPSF models.ConclusionsOur biomechanical FE analysis indicated the greater ability of OLIF + BPSF to retain lumbar stability, resist cage subsidence, and maintain disc height. Therefore, in the augmentation of OLIF, bilateral pedicle screws fixation may be the best approach.

Characterization of selected organometallic compounds by electrospray ionization- and matrix-assisted laser desorption/ionization-mass spectrometry using different types of instruments: Possibilities and limitations.

RationaleOrganometallic compounds are becoming increasingly important in their industrial application as catalysts. Mass spectrometry is an essential tool for the structural confirmation of such organometallics. Because the analysis of this class of molecules can be challenging, the ionization behavior and structural confirmation of selected transition metal catalysts are described in this work.MethodsThe transition metal catalysts investigated were analyzed using classical vacuum MALDI reflectron TOF‐MS as well as intermediate pressure matrix‐assisted laser desorption/ionization quadrupole time‐of‐flight mass spectrometry (MALDI QTOF‐MS). Obtained mass spectra were compared with electrospray ionization MS (ESI‐MS) already established for organometallic compounds, utilizing a QTOF mass spectrometer here. In addition, various sample preparations, including two selected MALDI matrices (trans‐2‐[3‐(4‐tert‐butylphenyl)‐2‐methyl‐2‐propenylidene]malononitrile and 2,2′:5′,2″‐terthiophene) with different solvent combinations for MALDI‐MS measurements, were investigated in detail with respect to their correct isotope distribution of the molecular ions observed.ResultsAll investigated organometallic compounds were successfully identified by vacuum and intermediate pressure MALDI‐MS. Accurate masses of ions related to molecular ion species (e.g., [M‐Cl]+, [M]+, and [M + Na]+) could be determined by MALDI QTOF‐MS measurements with a mass error of less than ±5 ppm for all compounds. Both investigated MALDI matrices performed equally on both instruments. The impact of the analyte/matrix solvent mixtures turned out to be crucial for a successful analysis of the investigated compounds. In contrast, ESI QTOF‐MS yielded masses of ions related to molecular ion species in favorable cases.ConclusionsThe use of MALDI‐MS for the structural confirmation of organometallic compounds is still not widely used. Nevertheless, this work showed that this analytical technique does have some benefits. The analysis of neutral catalysts proves to be quite useful, concluding that this technique provides a complement and/or an alternative to ESI‐MS.

The Financial Data Services Domain: From Taxonomies to Ontologies

There are many different types of instruments and hundreds of different markets for investment, leading to an extremely large and hard-to-define universe of financial data. The related commercial offer is extremely heterogeneous and complex. In this scenario, it is difficult to source the most appropriate financial services providers. In the past, eProcurement was mainly focused on the use of ERP management tools to record and examine previous buying decisions and expenditure data. In recent years, machine learning and artificial intelligence have been applied to procurement workflows, introducing computation of external or third party unstructured data to achieve a higher level of market knowledge and decision automation. In order to exploit the possibilities provided by these new technologies to the full extent possible, theoretical models for understanding large amounts of unstructured data are essential. In this research-in-progress paper we propose a taxonomy of financial data services and depict the related prototype ontological model, providing a possible conceptualisation and specification of the domain of interest potentially useful for the development of applications based on semantic technologies.

Improving the Quality of Human Upper Urinary Tract Specimens by Cryobiopsy.

ObjectiveThe quality of histopathological specimens obtained from the upper urinary tract with conventional flexible ureterorenoscopic biopsy needs to be improved. We investigated the feasibility and biopsy quality of specimens obtained by cryobiopsy, compared with standard ureterorenoscopic biopsy techniques in a human ex vivo model.Materials and MethodsHuman ureters obtained from nephrectomy specimens (N=12) were dissected and canulated with an ureteral access sheath. Ureterorenoscopic biopsies were randomly obtained from different sites of the renal pelvic caliceal system using different types of instruments. The performance of two newly developed flexible cryoprobes with outer diameters of 1.1 mm (CB11) and 0.9 mm (CB09) was compared with that of the biopsy forceps(FB) and Bigopsy®(BiG) and two different Dormia baskets N‐Gage (NG) and Zero‐Tip (ZT). We assessed the feasibility of the various biopsy techniques based on the number of biopsy attempts needed to obtain macroscopically discernible biopsies. The specimens were examined histopathologically for size, biopsy quality, presence of various artifact types, and representativeness.ResultsBiopsies taken with the cryoprobes showed a higher biopsy quality than biopsies taken with the comparative instruments. The CB11 provided significantly larger biopsies than forceps biopsies and also than biopsies with ZT. The CB09 was able to collect larger samples when compared with the FB and BiG biopsy forceps. There were no significant differences in artifact area, except for the CB11 cryoprobe compared with the NG. To clarify the results a subdivision of larger or smaller than 20% artifact area was performed. A significant difference was found between CB11 and the forceps biopsies, as well as between CB11 and NG and ZT in favor of the cryoprobe. The representation of the histopathological sample was also determined. Biopsies taken with CB11 were more representative compared with forceps biopsies BiG and FB and basket biopsies NG and ZT.ConclusionsIn a standardized comparative ex vivo setting, larger biopsies were obtained by using the cryobiopsy technique with the CB11 probe. Qualitatively, cryobiopsy specimens were overlaid by fewer artifacts and a higher biopsy quality was achieved in histopathologic examination compared with standard instrumentation. Further stepwise development will transfer the promising cryobiopsy technique into the clinical setting.

TeV Instrumentation: Current and Future

During the last 20 years, TeV astronomy has turned from a fledgling field, with only a handful of sources, into a fully-developed astronomy discipline, broadening our knowledge on a variety of types of TeV gamma-ray sources. This progress has been mainly achieved due to the currently operating instruments: imaging atmospheric Cherenkov telescopes, surface arrays and water Cherenkov detectors. Moreover, we are at the brink of a next generation of instruments, with a considerable leap in performance parameters. This review summarizes the current status of the TeV astronomy instrumentation, mainly focusing on the comparison of the different types of instruments and analysis challenges, as well as providing an outlook into the future installations. The capabilities and limitations of different techniques of observations of TeV gamma rays are discussed, as well as synergies to other bands and messengers.

Effect of Different Instrumentation and Irrigation Methods on Apical Microbial Extrusion: An Ex Vivo Study

Background: Periapical extrusion of debris, irrigating solution and microorganism are the major contributing factors for flare-ups during root canal therapy. The aim of this ex vivo study was to evaluate the effect of different types of instrumentation in combination with different irrigation methods on apical bacterial expulsion. Material and Methods: Three hundred and ten extracted human permanent teeth were infected with Enterococcus faecalis. After incubation at 37°C for 24 h, three hundred teeth were instrumented with three different instrumentations using two irrigation methods. The remaining ten teeth were used as negative and positive control groups, in which no inoculation was done and no instrumentation was carried out respectively. Three hundred teeth were equally divided in three groups (n = 100), in which instrumentation was performed using a protaper universal rotary file (group 1), WaveOne reciprocating file (group 2) and a flexiCON rotary file (group 3). In each group, 50 samples were irrigated with conventional needle irrigation, and 50 samples were irrigated with the endoVac irrigation method. During instrumentation, apically extruded bacteria were collected in an Eppendorf tube. Microbiological samples were taken from the Eppendorf tube and incubated for 24h, and colony-forming units were counted. The data collected were statistically analysed. Results: The group 2 showed highest bacterial extrusion using conventional irrigation while group 3 showed lowest using endovac irrigation system. Conclusion: FlexiCON rotary instrumentation with the endoVac irrigation system produced significantly less bacterial extrusion than the other techniques.

How to Encourage Energy Savings Behaviours? The Most Effective Incentives from the Perspective of European Consumers

Ongoing climate change and increasing energy consumption are becoming a serious threat to international development efforts. To ensure a secure and sustainable future, local, national and regional authorities, as well as energy companies, need to be involved in improving energy efficiency and promoting rational energy use. The consumer is always at the centre of interest of policy and energy reduction strategies makers. It is their behaviour, motives and beliefs that can lead to optimised and economical energy management. This paper responds to the need to identify the individual preferences of energy consumers. The presented research fills an existing gap in the literature by analysing the strength of the influence of different types of instruments and external stimuli shaping pro-environmental attitudes of consumers of different behavioural types. The analysis presented in this paper is the result of the next stage of the authors’ research on energy consumers modelling, their segmentation and comprehensive characteristics. The analysis was conducted on a representative sample of N = 4332 respondents from 8 European countries (Czech Republic, France, Greece, Spain, Germany, Poland, Romania, and the United Kingdom). The study used multivariate statistical methods, such as: Correspondence Analysis, Factor Analysis and Kruskal-Wallis test. These methods are adequate to the assumptions of the research procedure and allowed for the identification of 4 latent factors that link the incentives into groups, where the motivation to save energy is based on: information (“Information and Knowledge”), social norms (“Social Influence”), investment funding (“Investments”) and energy price changes (“Energy Price”). In addition, the level of effectiveness of the studied incentives and motivators depends on the behavioural type of energy consumers and increases with rising levels of their intrinsic pro-environmental motivation.

Improvement of Writing Skills Among Students With Hearing Impairment Using the Cognitive Model: An Experimental Study

Being a vital aspect of literacy, writing skills have great importance in the academics of students with hearing impairment. Improvement in writing skills is one of the prominent purposes of school education. Limitations in hearing impact the writing skills of students with hearing impairment (SWHI) in addition to reading skills. The present study was designed to highlight the writing problems of SWHI and to improve their creative writing skills using a cognitive model of teaching writing skills proposed by Flower and Hayes. The true experimental research design was used to see the impact of cognitive-based teaching strategies on the writing skills of SWHI. Pretest, treatment, posttest design were used to conduct this study. The targeted population for this research was SWHI studying in the grade 7th in the schools of Lahore city. A total number of 10 SWHI of Grade 7th was selected from one school in Lahore city. An equal number of students were assigned to control (N=5) and experimental group(N=5). Four different types of instruments were used to conduct the study. The experiment was conducted in one school in Lahore city for two months. The treatment comprised of instructional strategies developed in the light of Flower and Hayes's model of cognitive development. The study explored a statistically significantdifference between the writing skills of the students of the experimental group (EG) than the writing skills of the control group's students. The writing skills of students who belong to EG have upgraded after receiving treatment. The study recommended the use of cognitive-based strategies for the improvement of writing skills of students with hearing impairment.

Adobe as a resilient material and the causes of its disappearance in construction

The objective of this research is to value adobe constructions as buildings that must be preserved. The method applied to this research is qualitative, the objective is the description of the characteristics depending on the areas involved in resilience inductively, resulting from the proximity to empirical reality in municipalities of the state of Puebla, Mexico. The field research was conducted in Atlixco, Huaquechula, Tochimilco and Chietla, all municipalities in the State of Puebla and were used as examples as a result of direct observation. The stages of the research were: bibliographic analysis on the subject, the fieldwork was established with the planning of the fieldwork, data collection where instruments of different types were applied in each municipality and finally the systematization of the data from the fieldwork. It had the support of brigade groups from the Benemérita University of Puebla, BUAP and professors from the same institution.

Optimal Scheduling for Laboratory Automation of Life Science Experiments with Time Constraints.

In automated laboratories consisting of multiple different types of instruments, scheduling algorithms are useful for determining the optimal allocations of instruments to minimize the time required to complete experimental procedures. However, previous studies on scheduling algorithms for laboratory automation have not emphasized the time constraints by mutual boundaries (TCMBs) among operations, which is important in procedures involving live cells or unstable biomolecules. Here, we define the “scheduling for laboratory automation in biology” (S-LAB) problem as a scheduling problem for automated laboratories in which operations with TCMBs are performed by multiple different instruments. We formulate an S-LAB problem as a mixed-integer programming (MIP) problem and propose a scheduling method using the branch-and-bound algorithm. Simulations show that our method can find the optimal schedules of S-LAB problems that minimize overall execution time while satisfying the TCMBs. Furthermore, we propose the use of our scheduling method for the simulation-based design of job definitions and laboratory configurations.

The winter 2019 air pollution (PM&amp;lt;sub&amp;gt;2.5&amp;lt;/sub&amp;gt;) measurement campaign in Christchurch, New Zealand

Abstract. MAPM (Mapping Air Pollution eMissions) is a project whose goal is to develop a method to infer airborne particulate matter (PM) emissions maps from in situ PM concentration measurements. In support of MAPM, a winter field campaign was conducted in New Zealand in 2019 (June to September) to obtain the measurements required to test and validate the MAPM methodology. Two different types of instruments measuring PM were deployed: ES-642 remote dust monitors (17 instruments) and Outdoor Dust Information Nodes (ODINs; 50 instruments). The measurement campaign was bracketed by two intercomparisons where all instruments were co-located, with a permanently installed tapered element oscillating membrane (TEOM) instrument, to determine any instrument biases. Changes in biases between the pre- and post-campaign intercomparisons were used to determine instrument drift over the campaign period. Once deployed, each ES-642 was co-located with an ODIN. In addition to the PM measurements, meteorological variables (temperature, pressure, wind speed, and wind direction) were measured at three automatic weather station (AWS) sites established as part of the campaign, with additional data being sourced from 27 further AWSs operated by other agencies. Vertical profile measurements were made with 12 radiosondes during two 24 h periods and complimented measurements made with a mini micropulse lidar and ceilometer. Here we present the data collected during the campaign and discuss the correction of the measurements made by various PM instruments. We find that when compared to measurements made with a simple linear correction, a correction based on environmental conditions improves the quality of measurements retrieved from ODINs but results in over-fitting and increases the uncertainties when applied to the more sophisticated ES-642 instruments. We also compare PM2.5 and PM10 measured by ODINs which, in some cases, allows us to identify PM from natural and anthropogenic sources. The PM data collected during the campaign are publicly available from https://doi.org/10.5281/zenodo.4542559 (Dale et al., 2020b), and the data from other instruments are available from https://doi.org/10.5281/zenodo.4536640 (Dale et al., 2020a).

Scaling the Analytical Information Given by Several Types of Colorimetric and Spectroscopic Instruments Including Smartphones: Rules for Their Use and Establishing Figures of Merit of Solid Chemosensors.

The analytical information given by different types of instruments was scaled in order to establish suitably the figures of merit of a given methodology based on color measurements. Different lab and portable instruments, including smartphones with and without a miniaturized spectrophotometer accessory, have been tested. In order to obtain broad information and using objective criteria, these instruments have been compared from (1) the analytical point of view, considering mainly the detection limit (limits of detection [LODs]), selectivity, accuracy and intra- and interday precision, size, components, and costs; and (2) the environmental point of view, based on their footprint as kilograms of CO2. No significant differences in the precision were obtained with RSD (%) values lower than 10% for all of the instruments, but the achieved values of LOD, selectivity, accuracy, and cost were different. Footprints of CO2 were better for portable instrumentation, especially for smartphones. Three solid chemosensors made of different materials (PDMS, paper, or nylon) have been tested for the determination of ammonia and hydrogen sulfide at different concentration levels (ppb levels). As a result of this study, some rules for selecting the instrument for obtaining the required information have been established. Two apps have been developed for quantitation by smartphones, one for working with RGB values and the other for spectra obtained by the miniaturized spectrophotometer coupled to a smartphone.