LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 6 of total 6

Search options

  1. Article ; Online: Digital-movie-based flow colorimetry for pH measurement with universal indicators

    Selass Kebede Olbemo / Masaki Takeuchi / Hideji Tanaka

    Talanta Open, Vol 9, Iss , Pp 100279- (2024)

    1481  

    Abstract: A continuous, simple, and versatile pH monitoring method based on digital-movie-based colorimetry is proposed. A constructed flow system was of a two-channel configuration mainly composed of two peristaltic pumps, a digital microscope-based detector, a ... ...

    Abstract A continuous, simple, and versatile pH monitoring method based on digital-movie-based colorimetry is proposed. A constructed flow system was of a two-channel configuration mainly composed of two peristaltic pumps, a digital microscope-based detector, a pH meter with a flow-through combination pH-reference electrode, and a laptop computer. While the total flow rate (FT) was held constant, the flow rate (FB) of a base solution for Britton-Robinson buffer containing a universal indicator (Yamada's indicator or Van Urik's indicator) was changed in proportion to the control signal (Vc) from the computer. An acid solution for the buffer containing the indicator was aspirated to the confluence point at the flow rate of FT – FB and mixed with the base solution. Thus, buffer solutions with arbitrary pH could be easily prepared. The image of the mixed solution was captured with the microscope downstream; the pH of the solution was measured with the pH meter at the most downstream. An in-house program written in Visual Basic .NET was developed to control the system, acquire and analyze the signals (image data and pH), and display the results automatically; the color of the image was expressed as tristimulus values (i.e., R, G, B), hue, and luminance. The relationships between these color-specific values and pH were analyzed after optimizing the Vc scan rate. Van Uik's indicator was superior to Yamada's regarding the applicable pH range (ca. 2.5 – 10). A sigmoid-like calibration curve was established between hue and pH, which was used to determine sample pH. The proposed method was validated by measuring the pH of different drugs and vinegar samples.
    Keywords pH ; Digital movie-based colorimetry ; Universal indicator ; RGB ; Hue ; Analytical chemistry ; QD71-142
    Subject code 600
    Language English
    Publishing date 2024-08-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  2. Article ; Online: Parallel plate wet denuder coupled ammonia transfer device-conductivity detector for near-real-time monitoring of gaseous ammonia

    Haruka Tanaka / Makoto Namikawa / Naoya Tomiyasu / Hideji Tanaka / Masaki Takeuchi

    Talanta Open, Vol 5, Iss , Pp 100091- (2022)

    2022  

    Abstract: Gaseous ammonia (NH3) is a primary basic substance in the atmosphere, and its global emission has been increasing in recent decades. It is vital to continuously monitor the atmospheric NH3 to clarify the impact of NH3 on sensitive ecosystems. This paper ... ...

    Abstract Gaseous ammonia (NH3) is a primary basic substance in the atmosphere, and its global emission has been increasing in recent decades. It is vital to continuously monitor the atmospheric NH3 to clarify the impact of NH3 on sensitive ecosystems. This paper proposes a simple gaseous NH3 monitor utilizing a parallel plate wet denuder (PPWD) and a conductometric flow injection analysis (FIA) with an ammonia transfer device (ATD). In the present study, water-soluble basic gases, NH3, are selectively detected by the conductivity detector (CD). The ATD-CD ammonium detector requires no coloring reagents commonly used in FIA. Five-day field measurement of ambient NH3 was successfully performed with 30 min time resolution. All the air samples over the observation period (n = 186) contained NH3 above the limit of quantification (11.4 nmol m−3). The NH3 data showed excellent agreement with the values using ion chromatography in the field measurements.
    Keywords Ammonia ; Denuder ; Ammonia transfer device ; Conductivity detection ; Flow analysis ; Analytical chemistry ; QD71-142
    Subject code 621
    Language English
    Publishing date 2022-08-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  3. Article ; Online: Amplitude modulated flow analysis for speciation—Proof of concept by quantification of Fe2+ and Fe3+ ions

    Hideji Tanaka / Yohei Kurokawa / Masaki Takeuchi / Akira Ohbuchi

    Talanta Open, Vol 3, Iss , Pp 100031- (2021)

    2021  

    Abstract: We propose a novel concept of flow-based analysis for spectrophotometric speciation based on flow rate modulation and fast Fourier transform (FFT). A redox reagent solution's and a sample solution's flow rates are varied by sinusoidal control signals ... ...

    Abstract We propose a novel concept of flow-based analysis for spectrophotometric speciation based on flow rate modulation and fast Fourier transform (FFT). A redox reagent solution's and a sample solution's flow rates are varied by sinusoidal control signals with periods of T and 0.5T, respectively. Both solutions are merged with a color reagent, while the total flow rate is held constant. Downstream, the absorbance of the mixed solution is measured and acquired as the detector output voltage (Vd). The Vd is analyzed by FFT with the window's time length of T. One species that directly reacts with the color reagent contributes only to the amplitude (A2) of the second harmonic wave component in Vd. The other species that needs the redox conversion before the coloration contributes to the amplitude (A1) of the fundamental wave component, in addition to A2. The former species+' concentration can be estimated from A2 by taking the latter's contribution to A2 into account. The latter species’ concentration can be determined only from A1. The proposed concept was demonstrated by applying it to the speciation of Fe2+ and Fe3+ by an o-phenanthroline spectrophotometry, where Fe3+ was reduced to Fe2+ by L-ascorbic acid before the coloration.
    Keywords Flow analysis ; Flow rate modulation ; Fast Fourier transform ; Speciation ; Ferrous and ferric ions ; Amplitude modulation ; Analytical chemistry ; QD71-142
    Subject code 532 ; 621
    Language English
    Publishing date 2021-08-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  4. Article: Air segmented amplitude modulated multiplexed flow analysis with software-based phase recognition: Determination of phosphate ion

    Ogusu, Takeshi / Hideji Tanaka / Katsuya Uchimoto / Masaki Takeuchi

    Talanta. 2014 Jan. 15, v. 118

    2014  

    Abstract: Amplitude modulated multiplexed flow analysis (AMMFA) has been improved by introducing air segmentation and software-based phase recognition. Sample solutions, the flow rates of which are respectively varied at different frequencies, are merged. Air is ... ...

    Abstract Amplitude modulated multiplexed flow analysis (AMMFA) has been improved by introducing air segmentation and software-based phase recognition. Sample solutions, the flow rates of which are respectively varied at different frequencies, are merged. Air is introduced to the merged liquid stream in order to limit the dispersion of analytes within each liquid segment separated by air bubbles. The stream is led to a detector with no physical deaeration. Air signals are distinguished from liquid signals through the analysis of detector output signals, and are suppressed down to the level of liquid signals. Resulting signals are smoothed based on moving average computation. Thus processed signals are analyzed by fast Fourier transform. The analytes in the samples are respectively determined from the amplitudes of the corresponding wave components obtained. The developed system has been applied to the simultaneous determinations of phosphate ions in water samples by a Malachite Green method. The linearity of the analytical curve (0.0–31.0μmoldm−3) is good (r2>0.999) and the detection limit (3.3σ) at the modulation period of 30s is 0.52μmoldm−3. Good recoveries around 100% have been obtained for phosphate ions spiked into real water samples.
    Keywords air ; bubbles ; detection limit ; ions ; liquids ; malachite green ; phosphates
    Language English
    Dates of publication 2014-0115
    Size p. 123-128.
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 1500969-5
    ISSN 1873-3573 ; 0039-9140
    ISSN (online) 1873-3573
    ISSN 0039-9140
    DOI 10.1016/j.talanta.2013.10.001
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  5. Article: High Time-Resolution Monitoring of Free-Tropospheric Sulfur Dioxide and Nitric Acid at the Summit of Mt. Fuji, Japan

    Takeuchi, Masaki / Yuki Miyazaki / Hideji Tanaka / Takaharu Isobe / Hiroshi Okochi / Hiroko Ogata

    Water, air, and soil pollution. 2017 Sept., v. 228, no. 9

    2017  

    Abstract: This is the first paper that describes the atmospheric sulfur dioxide (SO₂) and nitric acid (HNO₃) monitored with a good time-resolution at the summit (3776 m a.s.l.), which is located in the free troposphere, and southeastern foot (1284 m a.s.l.) of Mt. ...

    Abstract This is the first paper that describes the atmospheric sulfur dioxide (SO₂) and nitric acid (HNO₃) monitored with a good time-resolution at the summit (3776 m a.s.l.), which is located in the free troposphere, and southeastern foot (1284 m a.s.l.) of Mt. Fuji. Japan. During the summer of 2012, two analytical systems consisting mainly of a parallel-plate wet denuder and ion chromatograph operated simultaneously at both the sampling sites. All the samples collected at both the sampling sites contained detectable levels of sulfate from gas-phase SO₂ while the nitrate from gas-phase HNO₃ was detectable in 97.8% of air samples at the southeastern foot and 88.4% at the summit. The average concentrations of SO₂ and HNO₃ were, respectively, 0.061 ± 0.071 and 0.031 ± 0.020 ppbv at the summit (n = 672), and 0.347 ± 0.425 and 0.146 ± 0.070 ppbv at the southeastern foot (n = 1344) of Mt. Fuji. Both the acidic gases at the southeastern foot and the HNO₃ at the summit showed a diurnal pattern with daytime maxima and nighttime minima. Meanwhile, the SO₂ at the summit did not show a distinct shift, which indicates the SO₂ concentrations at the summit would be principally controlled by the advection of air parcel in the free troposphere.
    Keywords advection ; air ; altitude ; chromatography ; diurnal variation ; monitoring ; nitrates ; nitric acid ; sulfates ; sulfur dioxide ; summer ; troposphere ; Japan
    Language English
    Dates of publication 2017-09
    Size p. 325.
    Publishing place Springer International Publishing
    Document type Article
    ZDB-ID 120499-3
    ISSN 1573-2932 ; 0049-6979 ; 0043-1168
    ISSN (online) 1573-2932
    ISSN 0049-6979 ; 0043-1168
    DOI 10.1007/s11270-017-3514-2
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

    In stock of ZB MED Bonn / Germany

    Z 2719: Show issues

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  6. Article ; Online: Buoyancy under control

    Timothée R Cook / Akiko Kato / Hideji Tanaka / Yan Ropert-Coudert / Charles-André Bost

    PLoS ONE, Vol 5, Iss 3, p e

    underwater locomotor performance in a deep diving seabird suggests respiratory strategies for reducing foraging effort.

    2010  Volume 9839

    Abstract: BACKGROUND: Because they have air stored in many body compartments, diving seabirds are expected to exhibit efficient behavioural strategies for reducing costs related to buoyancy control. We study the underwater locomotor activity of a deep-diving ... ...

    Abstract BACKGROUND: Because they have air stored in many body compartments, diving seabirds are expected to exhibit efficient behavioural strategies for reducing costs related to buoyancy control. We study the underwater locomotor activity of a deep-diving species from the Cormorant family (Kerguelen shag) and report locomotor adjustments to the change of buoyancy with depth. METHODOLOGY/PRINCIPAL FINDINGS: Using accelerometers, we show that during both the descent and ascent phases of dives, shags modelled their acceleration and stroking activity on the natural variation of buoyancy with depth. For example, during the descent phase, birds increased swim speed with depth. But in parallel, and with a decay constant similar to the one in the equation explaining the decrease of buoyancy with depth, they decreased foot-stroke frequency exponentially, a behaviour that enables birds to reduce oxygen consumption. During ascent, birds also reduced locomotor cost by ascending passively. We considered the depth at which they started gliding as a proxy to their depth of neutral buoyancy. This depth increased with maximum dive depth. As an explanation for this, we propose that shags adjust their buoyancy to depth by varying the amount of respiratory air they dive with. CONCLUSIONS/SIGNIFICANCE: Calculations based on known values of stored body oxygen volumes and on deep-diving metabolic rates in avian divers suggest that the variations of volume of respiratory oxygen associated with a respiration mediated buoyancy control only influence aerobic dive duration moderately. Therefore, we propose that an advantage in cormorants--as in other families of diving seabirds--of respiratory air volume adjustment upon diving could be related less to increasing time of submergence, through an increased volume of body oxygen stores, than to reducing the locomotor costs of buoyancy control.
    Keywords Medicine ; R ; Science ; Q
    Subject code 551
    Language English
    Publishing date 2010-01-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    Full text online

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

To top