1. Hendee, J., N. Amornthammarong, L. Gramer, and A. Gomez. A novel low-cost, high-precision sea temperature sensor for coral reef monitoring. Bulletin of Marine Science, 96(1):97-110, https://doi.org/10.5343/bms.2019.0050 2020


    The role of elevated sea temperatures in coral bleaching has been well documented. Many of the sea temperature records utilized for purposes of widespread, multi-species bleaching predictions in recent publications have been acquired through satellite remote sensing. Satellites estimate sea temperatures at only a narrow range of depths near the surface of the ocean and may, therefore, not adequately represent the true temperatures endured by the world’s coral ecosystems. To better characterize sea temperature regimes that coral reef ecosystems experience, as well as better define the individual thresholds for each species that bleaches, in situ sea temperature sensors are required. Commercial sensors are expensive in large quantities, however, reducing the capacity to conduct large-scale research programs to elucidate the range of significant scales of temperature variability. At the National Oceanic and Atmospheric Administration’s (NOAA) Atlantic Oceanographic and Meteorological Laboratory (AOML), we designed a low-cost (roughly US $9 in parts) and high-precision sea temperature sensor that uses an Arduino microprocessor board and a high accuracy thermistor. This new temperature sensor autonomously records temperatures onto a memory chip and provides better accuracy (+0.05°C) than a comparable commercial sensor (+0.2°C). Moreover, it is not difficult to build—anyone who knows how to solder can build the temperature sensor. In March 2019, students at middle and high schools in Broward County, Florida built close to 60 temperature sensors. During 2019, these sensors will be deployed by Reef Check, a global-scale coral reef monitoring organization, as well as by other programs, to determine worldwide sea temperature regimes through the Opuhala Project (https://www.coral.noaa.gov/opuhala). This paper chronicles results from the initial proof-of-concept deployments for these AOML-designed sensors.

  2. Obura, D.O., G. Aeby, N. Amornthammarong, W. Appeltans, N. Bax, J. Bishop, R.E. Brainard, S. Chan, P. Fletcher, T.A.C. Gordon, L. Gramer, M. Gudka, J. Halas, J. Hendee, G. Hodgson, D. Huang, M. Jankulak, A. Jones, T. Kimura, J. Levy, P. Miloslavich, L. Ming Chou, F.E. Muller-Karger, K. Osuka, M. Samoilys, S.D. Simpson, K. Tun, and S. Wongbusarakum. Coral reef monitoring, reef assessment technologies, and ecosystem-based management. Frontiers in Marine Science, 6:580, doi:10.3389/fmars.2019.0580 2019


    Coral reefs are exceptionally biodiverse and human dependence on their ecosystem services is high. Reefs experience significant direct and indirect anthropogenic pressures, and provide a sensitive indicator of coastal ocean health, climate change, and ocean acidification, with associated implications for society. Monitoring coral reef status and trends is essential to better inform science, management and policy, but the projected collapse of reef systems within a few decades makes the provision of accurate and actionable monitoring data urgent. The Global Coral Reef Monitoring Network has been the foundation for global reporting on coral reefs for two decades, and is entering into a new phase with improved operational and data standards incorporating the Essential Ocean Variables (EOVs) (www.goosocean.org/eov) and Framework for Ocean Observing developed by the Global Ocean Observing System. Three EOVs provide a robust description of reef health: hard coral cover and composition, macro-algal canopy cover, and fish diversity and abundance. A data quality model based on comprehensive metadata has been designed to facilitate maximum global coverage of coral reef data, and tangible steps to track capacity building. Improved monitoring of events such as mass bleaching and disease outbreaks, citizen science, and socio-economic monitoring have the potential to greatly improve the relevance of monitoring to managers and stakeholders, and to address the complex and multi- dimensional interactions between reefs and people. A new generation of autonomous vehicles (underwater, surface, and aerial) and satellites are set to revolutionize and vastly expand our understanding of coral reefs. Promising approaches include Structure from Motion image processing, and acoustic techniques. Across all systems, curation of data in linked and open online databases, with an open data culture to maximize benefits from data integration, and empowering users to take action, are priorities. Action in the next decade will be essential to mitigate the impacts on coral reefs from warming temperatures, through local management and informing national and international obligations, particularly in the context of the Sustainable Development Goals, climate action, and the role of coral reefs as a global indicator. Mobilizing data to help drive the needed behavior change is a top priority for coral reef observing systems.

  3. Carsey, T.P., S.J. Stamates, C.M. Featherstone, N. Amornthammarong, J.R. Bishop, C.J. Brown, A. Campbell, H.L. Casanova, M.L. Gidley, M. Kosenko, R.M. Kotkowski, J.V. Lopez, C.D. Sinagalliano, L.A. Visser, and J.-Z. Zhang. Broward County coastal ocean water quality study, 2010-2012. NOAA Technical Report, OAR-AOML-44, 217 pp., doi:10.7289/V5TD9VCC 2015


    Researchers with the Ocean Chemistry and Ecosystems Division of NOAA’s Atlantic Oceanographic and Meteorological Laboratory conducted 12 monthly cruises in two separate track lines off of Broward County, Florida, from November 2010 through January 2012. The cruise tracks were designed to provide information on three categories of the coastal ocean: (1) the vicinity of the Broward and Hollywood treated-wastewater outfalls; (2) the vicinity of the Hillsboro and Port Everglades inlets; and (3) the interstitial areas in between. Sampling took place from aboard the NOAA R/V Hildebrand using a conductivity-temperature-depth (CTD)/rosette for water samples and water column profiles and appropriately located acoustic Doppler current profiler (ADCP) instruments for ocean current information. Measured discrete parameters included location, depth, salinity, temperature, pH, oxygen saturation (dissolved oxygen, DO), oxidation-reduction (redox) potential (ORP), chlorophyll-a, phaeopigments, total suspended solids (TSS), nitrate (NO3), nitrite (NO2), ammonium (NH4), silicate (Si), orthophosphate (PO4), total dissolved nitrogen (TDN), total dissolved phosphorus (TDP), particulate carbon (PC), particulate phosphorus (PP), particulate nitrogen (PN), and dissolved organic carbon (DOC). CTD profile data included depth, turbidity, ORP, DO, pH, chlorophyll-a, salinity, temperature, and density. A variety of microbiological entities were measured, including fecal indicator bacteria (FIB), selected waterborne pathogens, and molecular microbial source tracking (MST) markers. Community bacterial metagenomic profiles were also generated for selected sample sites. Quality controls of nutrient sample analyses were obtained following National Environmental Laboratory Accreditation Conference (NELAC)-certified procedures. The data obtained present a view of the coastal ocean as having a low “background” concentration of most analytes, interrupted by elevated concentrations near the outfalls and inlets whose excess concentrations decreased rapidly away from the point sources. The waters were found to be oligotrophic, with no evidence of bloom events. A major upwelling event was observed on August 11, 2011, where a ~10°C temperature drop was observed near the southernmost portion of the sampled area.

  4. Amornthammarong, N., P.B. Ortner, J. Hendee, and R. Woosley. A simplified coulometric method for multi-sample measurements of total dissolved inorganic carbon concentration in marine waters. Analyst, 139(20):5263-5270, doi:10.1039/C4AN01049C 2014


    A new system requiring greatly reduced operator intervention has been developed for the determination of dissolved inorganic carbon concentration in marine waters. Based on a coulometric method, the system has an accuracy and precision comparable to more complex and expensive methods currently employed. A syringe pump equipped with a 12-port distribution valve is used to precisely dispense an acid solution and sample into a gas stripper. The system can autonomously measure eight discrete samples in duplicate or triplicate with no operator input. The best precision (%RSD) obtained was 0.022% (n = 14) or less than ±1.0 μmol kg−1. The system is calibrated against a certified reference material (CRM). Average offset from the CRM was 1.2 μmol kg−1. Sample throughput was 4 samples per h. Carryover effects are negligible but field sample analyses suggest that prefiltering may be necessary in highly turbid waters.

  5. Zhang, M., B.N. Stamos, N. Amornthammarong, and P.K. Dasgupta. Capillary scale admittance detection. Analytical Chemistry, 86(23):11538-11546, doi:10.1021/ac503245a 2014


    Techniques that have been variously termed oscillometric detection or (capacitively coupled) contactless conductivity detection (C4D) are known actually to respond to the admittance. It is not often appreciated that the frequency range (f) over which such systems respond (quasi)linearly with the cell conductance decreases acutely with increasing cell resistance. Guidance on optimum operating conditions for high cell resistance, such as for very small capillaries/channels and/or solutions of low specific conductance (σ), is scant. It is specially necessary in this case to take the capacitance of the solution into account. At high frequencies and low σ values, much of the current passes through the solution behaving as a capacitor and the capacitance is not very dependent on the exact solution specific conductance, resulting in poor, zero, or even negative response. We investigated, both theoretically and experimentally, capillaries with inner radii of 5–160 μm and σ ≈ 1–1400 μS/cm, resulting in cell resistances of 51 GΩ to 176 kΩ. A 400-element discrete model was used to simulate the behavior. As model inputs, both the wall capacitance and the stray capacitance were measured. The solution and leakage capacitances were estimated from extant models. The model output was compared to the measured response of the detection system over broad ranges of f and σ. Other parameters studied include capillary material and wall thickness, electrode spacing and length, Faraday shield thickness, excitation wave forms, and amplitude. The simulations show good qualitative agreement with experimental results and correctly predict the negative response behavior observed under certain conditions. We provide optimum frequencies for different operating conditions.

  6. Amornthammarong, N., J.-Z. Zhang, P.B. Ortner, J. Stamates, M. Shoemaker, and M.W. Kindel. A portable analyzer for the measurement of ammonium in marine waters. Environmental Science: Processes and Impacts, 15(3):579-584, doi:10.1039/C2EM30793F 2013

    Abstract: A portable ammonium analyzer was developed and used to measure in situ ammonium in the marine environment. The analyzer incorporates an improved LED photodiode-based fluorescence detector (LPFD). This system is more sensitive and considerably smaller than previous systems and incorporates a pre-filtering subsystem enabling measurements in turbid, sediment-laden waters. Over the typical range for ammonium in marine waters (0-10 µM), the response is linear (r2 = 0.9930) with a limit of detection (S/N ratio >3) of 10 nM. The working range for marine waters is 0.05-10 µM. Repeatability is 0.3% (n = 10) at an ammonium level of 2 µM. Results from automated operation in 15 min cycles over 16 days had good overall precision (RSD = 3%, n = 660). The system was field tested at three shallow South Florida sites. Diurnal cycles and possibly a tidal influence were expressed in the concentration variability observed.

  7. Carsey, T.P., S.J. Stamates, N. Amornthammarong, J.R. Bishop, F. Bloetscher, C.J. Brown, J.F. Craynock, S.R. Cummings, W.P. Dammann, J. Davis, C.M. Featherstone, C.J. Fischer, K.D. Goodwin, D.E. Meeroff, J.R. Proni, C.D. Sinigalliano, P.K. Swart, and J.-Z. Zhang. Boynton Inlet 48-hour sampling intensives: June and September 2007. NOAA Technical Report, OAR-AOML-40, 43 pp., 2012


    Researchers with the Ocean Chemistry Division of NOAA’s Atlantic Oceanographic and Meteorological Laboratory performed two 48-hour intensive studies of the water flowing through the Boynton Inlet at Boynton Beach, Florida, during June and September 2007. These studies were conducted in support of the Florida Area Coastal Environment (FACE) program. Academic partners who also participated in the effort included colleagues with the University of Miami’s Cooperative Institute for Marine and Atmospheric Studies and the Rosenstiel School of Marine and Atmospheric Science, Florida Atlantic University’s Laboratories for Engineered Environmental Solutions, and the Applied Research Center of Florida International University. Sampling was performed from the southern boardwalk at Boynton Beach during the June intensive and the Boynton Beach Inlet Bridge during the September intensive. The sampling strategy was designed to collect water samples over four complete tidal cycles for each intensive; these data would be employed to quantify the total flux of nearshore-source entities into the coastal waters. The first sampling event was conducted on June 4-6, 2007, and the second was conducted on September 26-28, 2007. Data collected include nutrients (silicate, orthophosphate, ammonium, nitrite+nitrate), isotope ratios of nitrogen, the presence or absence of selected biological indicators (Escherichia coli, enterococci, and total coliform), and physical parameters that included pH, salinity, total suspended solids, and turbidity. Critical to this study was the continuous in situ flow rate measurements obtained via an acoustic Doppler current profiler (ADCP) mounted on the north side of the inlet. This report presents the data gathered from the two sampling intensives. The data reported herein suggest that inlets are important contributors of nutrient and microbiological loads to the coastal zone. The overall view presented is that the lagoon input into Boynton Inlet may be substantial but is also highly variable.

  8. Hendee, J., L.J. Gramer, S.F. Heron, M. Jankulak, N. Amornthammarong, M. Shoemaker, T. Burgess, J. Fajans, S. Bainbridge, and W. Skirving. Wireless architectures for coral reef environmental monitoring. Proceedings, 12th International Coral Reef Symposium, D. Yellowlees and T.P. Hughes (eds.), Cairns, Australia, July 9-13, 2012. ARC Centre of Excellence for Coral Reef Studies, James Cook University, 5 pp., 2012

    Abstract: Over the last ten years several wireless architectures have been developed for transmitting meteorological and oceanographic data (in real-time or near real-time) from coral reef ecosystems in Florida, the Caribbean, Saipan, and Australia. These architectures facilitate establishing trends in environmental parameters and aid in ecosystem modeling and ecological forecasting. Here, existing architectures, as well as those currently in development, are described, incorporating use of Geostationary Operational Environmental Satellites, radio transceivers, wireless digital cellular modems, mobile wireless hotspots, and Android phones. Each architecture is reviewed for advantages and disadvantages, along with some examples of deployments. These summaries provide reef managers and scientists with a suite of options for monitoring, allowing the selection of the most appropriate architecture for the particular needs and capacities of each coral reef location.

  9. Mantim, T., P. Saetear, S. Teerasong, S. Chan-Eam, K. Sereenonchai, N. Amornthammarong, N. Ratanawimarnwong, P. Wilairat, W. Meesiri, K. Uraisin, and D. Nacapricha. Reagent-free analytical flow methods for the soft drink industry: Efforts for environmentally friendly chemical analysis. Pure and Applied Chemistry, 84(10):2015-2025, doi:10.1351/PAC-CON-12-02-06 2012


    The evolution of an entirely green analytical system for industrial quality control of carbonated drinks is described. The developed flow system is capable of providing analytical data of the dissolved CO2, sucrose, and color of a sample consecutively in real-time. The system has been carefully designed on the basis of "reagent-free," meaning that no added chemicals are required for the analysis. The system first vaporizes CO2 from the soft drink in a gas-liquid separation chamber, with a channel for a flow of pure water as the CO2 acceptor. The dissolved CO2 alters the conductivity of the water stream, which is directly related to the concentration of CO2 in the soft drink. The sucrose content is measured based on the "Schlieren effect," the sample plug flows out of the vaporization chamber into a colorimeter with a near-infrared/light-emitting diode (NIR/LED) as light source. The Schlieren effect arises at the boundary of pure water and soft drink with refraction of light in proportion to the sugar concentration. The system also measures the absorbance of the sample using an RGB-LED. The related principles and preliminary experiments as proof of concept are described as well as the construction of the flow system for this completely reagent-free analyzer. A simple flow injection system using the Schlieren effect was also developed for rapid quantitative analysis of sugar in noncarbonated soft drinks.

  10. Amornthammarong, N., J.-Z. Zhang, and P.B. Ortner. An autonomous batch analyzer for the determination of trace ammonium in natural waters using fluorometric detection. Analytical Methods, 3(7):1501-1506, doi:10.1039/C1AY05095H 2011


    An autonomous batch analyzer (ABA) is described for the measurement of ammonium in natural waters. The system combines previously described batch analysis and continuous flow analysis methods. With its simpler design, the system is robust, flexible, inexpensive, and requires minimal maintenance. The sampling frequency is ca. 8 h-1 and the limit of detection ca. 1 nM which is comparable to the most sensitive flow through or batch analysis methods previously described. Reproducibility is 0.6% (n = 10) at an ammonium level of 200 nM. There are three working ranges: 5-1000 nM, 20-4000 nM, and 0.2-25 μM. In addition, the system produces a calibration curve by autodilution from a single stock standard solution with the same accuracy as traditional manual calibration methods. Representative field data and comparisons with standard EPA methods confirm the utility of the ABA.

  11. Amornthammarong, N., P.B. Ortner, and J.-Z. Zhang. A simple, effective mixing chamber used in conjunction with a syringe pump for flow analysis. Talanta, 81(4-5), 1472-1476, doi:10.1016/j.talanta.2010.02.054 2010

    Abstract: A simple, effective mixing chamber used in conjunction with a syringe pump for flow analysis is described and evaluated. A mixing chamber was constructed using a conventional 5 mL pipette tip and its performance compared with a widely used mixing coil. The results demonstrate that the mixing coil does not rapidly and completely mix solutions. Utilizing a configuration that reversed solution positions in the chamber with each mixing cycle, the proposed mixing chamber achieved complete mixing in a significantly shorter time than the mixing coil. The influence of injected sample volume on absorbance signals was evaluated by calculating an S1/2 value for the system. As tested with a minimal rinse, the system has no discernable carryover. Testing this new approach in our previously described silicate measurement system resulted in a more than twofold improvement in sensitivity.

  12. Sereenonchai, K., S. Teerasong, S. Chan-Eam, P. Saetear, N. Choengchan, K. Uraisin, N. Amornthammarong, S. Motomizu, and D. Nacapricha. A low-cost method for determination of calcium carbonate in cement by membraneless vaporization with capacitively coupled contactless conductivity detection. Talanta, 81(3):1040-144, doi:10.1016/j.talanta.2010.01.057 2010

    Abstract: This work presents a flow analysis method for direct quantitation of calcium carbonate in cement without pretreatment of the sample. The method is based on online vaporization of CO2 gas following acidification of the sample inside a small chamber that has a flow of acceptor solution passing around it. Solubilization of the CO2 gas into the acceptor stream changes the conductivity of the acceptor solution, causing an increase of signal at the capacitively coupled contactless conductivity detection (C4D) placed at the outlet of the vaporization chamber. This chamber is an adaption from previous work reported on membraneless vaporization (MBL-VP). The method can be used in the quality control of production of mixed cement. These cement materials usually have calcium carbonate contents at high concentration range (e.g., 33-99% (w/w) CaCO3). Analysis of samples by this method is direct and convenient, as it requires no sample pretreatment. The method is low-cost with satisfactory accuracy and acceptable precision.

  13. Teerasong, S., N. Amornthammarong, K. Grudpan, N. Teshima, T. Sakai, D. Nacapricha, and N. Ratanawimarnwong. A multiple processing hybrid flow system for analysis of formaldehyde contamination in food. Analytical Sciences, 26(5):629-633, doi:10.2116/analsci.26.629 2010


    This work proposes a flow system suitable for the rapid screening of formaldehyde contaminated in food. The system is based on the concept of a flow analyzer with a Hantzsch reaction. An operating procedure was developed for multiple tasking and high sample throughput. This resulted in a significant sample throughput of 51 samples h-1. Under the optimized conditions, linear calibration from 10 to 100 µM was obtained. The system gave a limit of detection and a limit of quantitation of 0.06 and 0.10 mg kg-1, respectively. The system was successfully applied to rehydrated dry squids, vegetables, and mushrooms.

  14. Teerasong, S., S. Chan-Eam, K. Sereenonchai, N. Amornthammarong, N. Ratanawimarnwong, and D. Nacapricha. A reagent-free SIA module for monitoring of sugar, color, and dissolved CO2 content in soft drinks. Analytica Chimica Acta, 668(1):47-53, doi:10.1016/j.aca.2010.01.021 2010


    This work presents a new sequential injection analysis (SIA) method and a module for simultaneous and real-time monitoring of three key parameters for the beverage industry, i.e., the sugar content (measured in Brix), color, and dissolved CO2. Detection of the light reflection at the liquid interface (the Schlieren effect) of sucrose and water was utilized for sucrose content measurement. A near infrared LED (890 ± 40 nm) was chosen as the light source to ensure that all the ingredients and dyes in the soft drinks did not interfere by contributing light absorption. A linear calibration was obtained for sucrose over a wide concentration range (3.1-46.5 Brix). The same module can be used to monitor the color of the soft drink, as well as the dissolved CO2 during production. For measuring the color, the sample is segmented between air plugs to avoid dispersion. An RGB-LED was chosen as the light source in order to make this module applicable to a wide range of colored samples. The module also has a section where dissolved CO2 is measured via vaporization of the gas from the liquid phase. Dissolved CO2, in a flowing acceptor stream of water resulting in the change of the acceptor conductivity, is detected using an in-house capacitively coupled contactless conductivity detector (C4D). The module includes a vaporization unit that is also used to degas the carbonated drink, prior to the measurements of sucrose and color within the same system. The method requires no chemicals and is therefore completely friendly to the environment.

  15. Amornthammarong, N., and J.-Z. Zhang. Liquid-waveguide spectrophotometric measurement of low silicate in natural waters. Talanta, 79(3):621-626, doi:10.1016/j.talanta.2009.04.050 2009


    This paper describes a robust, sensitive method for measurement of low silicate in natural water. The method is based on the reaction of silicate with ammonium molybdate to form a yellow silicomolybdate complex, which is then reduced to silicomolybdenum blue by ascorbic acid. This method shows no refractive index effect and a small salinity effect that can be corrected for seawater samples. It was found that the use of poly-vinyl alcohol can prevent the precipitation formation in the ammonium molybdate solution and improve the stability of the silicomolybdenum blue complex. The sensitivity of this method is substantially enhanced by using a liquid-waveguide capillary cell. The detection limit is 0.1 µM and the working range is 0.1-10 µM for using a 2-m liquid-waveguide capillary cell (LWCC). The method can be used for both freshwater and seawater samples and has been used to study the distribution of silicate in surface seawater of Gulf Stream in the Florida Straits.

  16. Amornthammarong, N., D. Nacapricha, K. Sereenonchai, P. Anujarawat, and P. Wilairat. Audible-wave telemetry with PC sound card for remote analysis applications. In Telemetry: Research, Technology, and Applications, D. Barculo and J. Daniels (eds.). Nova Science Publishers, New York, 205-214, 2009

    Abstract: This chapter describes the development of a cost-effective telemetric system through a combination of a wireless microphone for signal transmission and a computer sound card for recording of signals in the audible range. Three common communication systems, which are normally used for voice transmission, were compared for data transmission. The final developed telemeter provides a high potential for remote monitoring up to a distance of 30 m with a sampling rate of 10 Hz and 100% accuracy with low noise. The working signal range was from 0 to o2 volts, with resolution of more than a 10 bit A/D. A satisfactorily good precision of 0.1% RSD was achieved. The system works well for wireless monitoring of output from a spectrophotometer and pH meter. This work also demonstrated successful applications of the telemetric system with various chemical analyses in our laboratory.

  17. Carsey, T., K.D. Goodwin, J. Hendee, J.R. Proni, C. Sinigalliano, J. Stewart, J.-Z. Zhang, N. Amornthammarong, J. Craynock, S. Cummings, P. Dammann, C. Featherstone, J. Stamates, and K. Sullivan. A glimpse of the Florida Area Coastal Environment (FACE) program. Proceedings, 11th International Coral Reef Symposium, Ft. Lauderdale, FL, July 7-11, 2008. International Society for Reef Studies, 559-563, 2009

    Abstract: The Florida Area Coastal Environment (FACE) research program gathers a variety of data related to water inputs into the coastal zone of southeast Florida. The water inputs studied include treated wastewater discharges, inlet flows, and upwelling events. Measurements include currents, nutrients, microbial contaminants, and stable isotopes. This report provides a glimpse of the data collected in this program. Data collected from the Boynton inlet point to the significance of this discharge as a source of nutrient and microbiological loads to coastal waters and demonstrate the importance of accounting for all major discharges in order to fully understand the impact of land use and water management decisions on coastal resources.

  18. Amornthammarong, N., and J.-Z. Zhang. Shipboard fluorometric flow analyzer for high-resolution underway measurement of ammonium in seawater. Analytical Chemistry, 80(4):1019-1026, doi:10.1021/ac701942f 2008

    Abstract: A shipboard fluorometric flow analyzer has been developed for near-real-time, high-resolution underway measurement of ammonium in seawater. The fluorometric method is based on the reaction of ammonium with o-phthaldialdehyde (OPA) and sulfite. The reagents used in this method have been modified to suit seawater analysis. This method shows no refractive index and salinity effect from seawater samples. The potential interferences in seawater have been studied, and their effects have been reduced. The instrument response is linear over a wide range of ammonium concentration. The limit of detection of 1.1 nM was estimated in laboratory using ammonium standards prepared in distilled water. It should be noted that application of this method to low-level ammonium measurement requires a correction of interference species, such as amino acids. The sample throughput is 3600 h-1. The system can be used for both freshwater and seawater samples and has been used to monitor the distribution of ammonium in Florida coastal waters around an oceanic wastewater outfall.

  19. Nacapricha, D., N. Amornthammarong, K. Sereenonchai, P. Anujarawat, and P. Wilairat. Low cost telemetry with PC sound card for chemical analysis applications. Talanta, 71(2):605-609, doi:10.1016/j.talanta.2006.05.004 2007


    This work describes the development of a telemetric system in conjunction with a computer sound card for recording of signals. For signal transmission, a transmission wireless microphone was utilized, making the telemeter compatible with the sound card normally equipped inside a personal computer. The developed telemeter is a low-cost apparatus capable of remote monitoring. With the sampling rate of 10 Hz, 100% accuracy was obtained up to a distance of 30 m. The precision was good (% RSD = 0.03-0.09), with relatively low noise. The effective signal range was from 0 to 2 V, with approximately 1100 working steps (greater than 10 bit A/D). The telemetric system was shown to be suitable for wireless recording of outputs from spectrophotometer and pH meter. Potential applications in chemical analysis were demonstrated.

  20. Sereenonchai, K., P. Saetear, N. Amornthammarong, K. Uraisin, P. Wilairat, S. Motomizu, and D. Nacapricha. Membraneless vaporization unit for direct analysis of solid sample. Analytica Chimica Acta, 597(1):157-162, doi:10.1016/j.aca.2007.06.036 2007


    A new apparatus, called "membraneless vaporization" (MBL-VP) unit was designed and developed for direct analysis of solid samples. Solid analyte was converted into a gaseous form which then reacts with an indicator reagent. Change in absorbance was used to quantitate the analyte. Stirring with a magnetic bar was employed to facilitate the evaporation of the gas. Unlike the pervaporation technique, hydrophobic membrane was not required for this MBL-VP technique. Application of the membraneless technique for direct determination of calcium carbonate in calcium supplements, has shown it to be very precise (RSD = 2.5% for 0.16 mmol CO32-), with detection limit of 0.5 mg CaCO3. Results by this method agreed well with flame atomic absorption spectrometric method. Sample throughput was 20 samples h-1.