scholarly journals Technical note: Interpreting pH changes

2021 ◽  
Vol 18 (4) ◽  
pp. 1407-1415
Author(s):  
Andrea J. Fassbender ◽  
James C. Orr ◽  
Andrew G. Dickson
Keyword(s):  
Technical Note ◽  
Ion Concentration ◽  
Ph Change ◽  
Ph Measurements ◽  
Hydrogen Ion Concentration ◽  
Ph Changes ◽  
The Past ◽  
Initial Ph ◽  
Relative Change

Abstract. The number and quality of ocean pH measurements have increased substantially over the past few decades such that trends, variability, and spatial patterns of change are now being evaluated. However, comparing pH changes across domains with different initial pH values can be misleading because a pH change reflects a relative change in the hydrogen ion concentration ([H+], expressed in mol kg−1) rather than an absolute change in [H+]. We recommend that [H+] be used in addition to pH when describing such changes and provide three examples illustrating why.

scholarly journals Technical note: Interpreting pH changes

2020 ◽  
Author(s):  
Andrea J. Fassbender ◽  
James C. Orr ◽  
Andrew G. Dickson
Keyword(s):  
Technical Note ◽  
Ion Concentration ◽  
Ph Change ◽  
Ph Measurements ◽  
Hydrogen Ion Concentration ◽  
Ph Changes ◽  
The Past ◽  
Initial Ph ◽  
Relative Change

Abstract. The number and quality of ocean pH measurements has increased substantially over the past few decades such that trends, variability, and spatial patterns of change are now being evaluated. However, comparing pH changes across domains with different initial pH values can be misleading because a pH change reflects a relative change in the hydrogen ion concentration ([H+]–expressed in mol kg−1) rather than an absolute change in [H+]. We recommend that [H+] be used in addition to pH when describing such changes and provide three examples illustrating why.

scholarly journals Technical note: Stability of tris pH buffer in artificial seawater stored in bags

Ocean Science ◽  
2021 ◽  
Vol 17 (3) ◽  
pp. 819-831
Author(s):  
Wiley H. Wolfe ◽  
Kenisha M. Shipley ◽  
Philip J. Bresnahan ◽  
Yuichiro Takeshita ◽  
Taylor Wirth ◽  
...  
Keyword(s):  
Dissolved Inorganic Carbon ◽  
Technical Note ◽  
Artificial Seawater ◽  
Upper And Lower Bounds ◽  
Sensor Calibration ◽  
Time Data ◽  
Ph Change ◽  
Ph Measurements ◽  
Experimental Conditions ◽  
Initial Ph

Abstract. Equimolal tris (2-amino-2-hydroxymethyl-propane-1,3-diol) buffer in artificial seawater is a well characterized and commonly used standard for oceanographic pH measurements. We evaluated the stability of tris pH when stored in purportedly gas-impermeable bags across a variety of experimental conditions, including bag type and storage in air vs. seawater over 300 d. Bench-top spectrophotometric pH analysis revealed that the pH of tris stored in bags decreased at a rate of 0.0058±0.0011 yr−1 (mean slope ±95 % confidence interval of slope). The upper and lower bounds of expected pH change at t=365 d, calculated using the averages and confidence intervals of slope and intercept of measured pH change vs. time data, were −0.0042 and −0.0076 from initial pH. Analyses of total dissolved inorganic carbon confirmed that a combination of CO2 infiltration and/or microbial respiration led to the observed decrease in pH. Eliminating the change in pH of bagged tris remains a goal, yet the rate of pH change is lower than many processes of interest and demonstrates the potential of bagged tris for sensor calibration and validation of autonomous in situ pH measurements.

Hydro-geochemical properties with respect to landuse in the southernmost river of Kerala

2018 ◽  
Vol 6 (1) ◽  
Author(s):  
Badusha M. ◽  
Santhosh S
Keyword(s):  
Organic Carbon ◽  
Drainage Basin ◽  
Anthropogenic Activities ◽  
Oxygen Demand ◽  
Ion Concentration ◽  
Total Hardness ◽  
Hydrogen Ion Concentration ◽  
Geochemical Properties ◽  
Quality Of Water

The hydro geochemical features of Neyyar River for a period of one year from May 2015 to April 2016 were analyzed. Six sampling sites were fixed considering physiography and present landuse pattern of the river basin. The residents in the drainage basin are primarily responsible for framing a better landuse and thereby maintain a good water and sediment regime. Geospatial pattern of the present landuse of the study area indicated that the sustainability of this river ecosystem is in danger due to unscientific landuse practices, which is reflected in the river quality as well. The parameters such as hydrogen ion concentration, electrical conductivity, chloride, Biological Oxygen Demand, total hardness and sulphate of river water and Organic Carbon of river bed sediments were analyzed in this study. The overall analysis shows that the highland areas are characterized by better quality of water together with low organic carbon, which is mainly due to better landuse and minimal reclamation. The midland and lowland areas are characterized by poor quality of water with high organic carbon, which is due to high anthropogenic activities and maximum pollutants associated with the region together with the alteration in landuse from a traditional eco-friendly pattern to a severely polluted current pattern.

Alkaline milk and its detection by the brom cresol purple test—I

1926 ◽  
Vol 16 (1) ◽  
pp. 145-148
Author(s):  
F. Procter ◽  
A. T. R. Mattick
Keyword(s):  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
The Past ◽  
Starting Point ◽  
Liquid Milk ◽  
Ortho Cresol

During the past five years many appeals for assistance have been received at this Institute from cheesemakers in various parts of the country, who from time to time have found, themselves unable to secure satisfactory coagulation of their milk by rennet by reason of some abnormality which is not patent to the eye.Difficulties are also encountered in the liquid milk trade from causes which appear to resemble those which trouble the cheesemaker.In view of the necessity for detecting milk such as this, use has been made of di-brom-ortho-cresol-sulphon-phthalein or brom cresol purple, which indicates colorimetrically the reaction or hydrogen-ion concentration of milk, and provides a starting point for the further investigation of those samples of which the reaction is abnormal.

scholarly journals The Influence of Hydrogen Ion Concentration on Calcium Binding and Release by Skeletal Muscle Sarcoplasmic Reticulum

1972 ◽  
Vol 59 (1) ◽  
pp. 22-32 ◽  
Author(s):  
Yoshiaki Nakamaru ◽  
Arnold Schwartz
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Calcium Binding ◽  
Calcium Release ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Ph Change ◽  
Release Process ◽  
Hydrogen Ion Concentration ◽  
Calcium Loading

Calcium release and binding produced by alterations in pH were investigated in isolated sarcoplasmic reticulum (SR) from skeletal muscle. When the pH was abruptly increased from 6.46 to 7.82, after calcium loading for 30 sec, 80–90 nanomoles (nmole) of calcium/mg protein were released. When the pH was abruptly decreased from 7.56 to 6.46, after calcium loading for 30 sec, 25–30 nmole of calcium/mg protein were rebound. The calcium release process was shown to be a function of pH change: 57 nmole of calcium were released per 1 pH unit change per mg protein. The amount of adenosine triphosphate (ATP) bound to the SR was not altered by the pH changes. The release phenomenon was not due to alteration of ATP concentration by the increased pH. Native actomyosin was combined with SR in order to study the effectiveness of calcium release from the SR by pH change in inducing super-precipitation of actomyosin. It was found that SR, in an amount high enough to inhibit superprecipitation at pH 6.5, did not prevent the process when the pH was suddenly increased to 7.3, indicating that the affinity of SR for calcium depends specifically on pH. These data suggest the possible participation of hydrogen ion concentration in excitation-contraction coupling.

Hydrogen-Ion Concentration and the Distribution of Limnaea truncatula and L. peregra, with a Note bearing on Mosquitoes

Parasitology ◽  
1926 ◽  
Vol 18 (4) ◽  
pp. 363-367 ◽  
Author(s):  
C. L. Walton ◽  
W. Rees Wright
Keyword(s):  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Amount Of Information ◽  
The Past ◽  
North Wales

During the past few months we have collected a considerable amount of information relating to the value of pH. as affecting the distribution of the three species of Limnaea commonly found in North Wales. Tables I and II show that L. truncatula occurs over a range of pH. 6·0 to 8·6, and L. peregra 5·8 to 8·8; L. palustris was recorded from 7·4 to 8·0 (but only three of the readings included this species).

Effect of host dietary constituents on intestinal pH and the migrational behavior of the rat tapeworm Hymenolepis diminuta

1971 ◽  
Vol 49 (12) ◽  
pp. 1513-1525 ◽  
Author(s):  
D. F. Mettrick
Keyword(s):  
Small Intestine ◽  
Olive Oil ◽  
Dry Weight ◽  
Amino Acid Mixture ◽  
Hymenolepis Diminuta ◽  
Ion Concentration ◽  
Acid Mixture ◽  
Ph Gradients ◽  
Hydrogen Ion Concentration

Changes in intestinal pH and in the position of Hymenolepis diminuta within the rat small intestine, have been followed for up to 7 h after feeding a 2.5-ml meal containing either 1 g or 3 g glucose, 2 g dextrin, 2 g galactose, 2 ml olive oil or an amino acid mixture containing 2.5 μmoles of 18 different amino acids.Both the quantity and quality of the dietary constituents have statistically significant effects (P < 0.001) on the pH gradients in the small intestine at any time up to 7 h after feeding. This implies that the buffering system of the rat is unable to maintain a very efficient homeostatic control of the hydrogen ion concentration in the intestine. The changes in intestinal pH are neither the cause of, nor are directly caused by, the migrational movements of the worms.The migrational response of the worms, which involved both scolex attachment sites and worm biomass (dry weight), varied depending on the quantity and quality of the meal.While the pattern of the migrational response was very similar following the feeding of 1 g and 3 g glucose, there was a 3-h delay after feeding 3 g glucose before the worms attained the maximum anteriad migrational position. Although there was an anteriad migration of worm biomass following the feeding of all the carbohydrates tested, the most marked anteriad movement was in response to feeding olive oil. Glucose does not appear to be the direct stimulus controlling the migrational behavior of H. diminuta.

Predicting lime-induced changes in soil-pH From exchangeable aluminum, soil-Ph, total exchangeable cations and organic-carbon values measured on unlimed soils

Soil Research ◽  
1995 ◽  
Vol 33 (1) ◽  
pp. 31 ◽  
Author(s):  
Z Hochman ◽  
GJ Crocker ◽  
EB Dettman
Keyword(s):  
Organic Carbon ◽  
Soil Ph ◽  
Field Experiments ◽  
Acid Soils ◽  
Exchangeable Cations ◽  
Ion Concentration ◽  
Soil Parameters ◽  
Ph Change ◽  
Data Set ◽  
Hydrogen Ion Concentration

The 'Lime-it' model is a decision support system for graziers wanting to lime acid soils. In this study we used field experimental data to test, improve and validate the model's ability to predict changes in soil pH due to variable rates of lime. Data from 13 field experiments, in which soil parameters were measured 1 year after liming acid soils, were used to derive an index of pH responsiveness to lime (LRI) at each site. Multivariate analysis was used to derive a predictive model: LRI was found to be significantly correlated (P < 0.0001) with hydrogen ion concentration ([H+]x 105 ), exchangeable aluminium (Al), exchangeable cations (TEC) and percent organic carbon (C) data of the unlimed soils. The multivariate equation was then tested against an independent data set by comparing the predicted pH change with the measured pH change for eight soils. This evaluation, though generally acceptable, showed a small but significant deviation from the desired 1:1 ratio between observed and predicted pH change. We re-calibrated the model for the combined data to derive the model: LRI = 0.764 + 0.042 [H+] - 0.016 TEC - 0.097 Al - 0.016 C. When this model was tested over the whole data set for predicted v. measured pH changes, the following result was found: measured pH change = 1.01 (predicted pH change) - 0.05 (R2 = 0.85, n = 308). The implications of the predictive equation are considered with regard to the mechanisms that are thought to be associated with pH buffering.

scholarly journals A Multi-Scale Approach to Microencapsulation by Interfacial Polymerization

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 644
Author(s):  
Fabián Ricardo ◽  
Diego Pradilla ◽  
Ricardo Luiz ◽  
Oscar Alberto Alvarez Solano
Keyword(s):  
Interfacial Polymerization ◽  
Process Variables ◽  
Compression Force ◽  
Ph Change ◽  
Ph Measurements ◽  
Kinetics Of Polymerization ◽  
Multi Scale ◽  
Ph Values ◽  
Initial Ph ◽  
Kinetics Of

This work applies a multi-scale approach to the microencapsulation by interfacial polymerization. Such microencapsulation is used to produce fertilizers, pesticides and drugs. In this study, variations at three different scales (molecular, microscopic and macroscopic) of product design (i.e., product variables, process variables and properties) are considered simultaneously. We quantify the effect of the formulation, composition and pH change on the microcapsules’ properties. Additionally, the method of measuring the strength of the microcapsules by crushing a sample of microcapsules’ suspension was tested. Results show that the xylene release rate in the microcapsules decreases when the amine functionality is greater due to a stronger crosslinking. Such degree of crosslinking increases the compression force over the microcapsules and improves their appearance. When high levels of amine concentration are used, the initial pH values in the reaction are also high which leads to agglomeration. This study provides a possible explanation to the aggregation based on the kinetic and thermodynamic controls in reactions and shows that the pH measurements account for the polyurea reaction and carbamate formation, which is a reason why this is not a suitable method to study kinetics of polymerization. Finally, the method used to measure the compressive strength of the microcapsules detected differences in formulations and composition with low sensibility.

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