pH Measurement and Control

1	Introduction and Theory
1.1	Importance of pH Measurements
1.2	pH Definition and pH Buffers
1.3	Activities
1.4	Self-Dissociation
2	pH Measurement and Technologies
2.1	Electrochemical Methods
2.2	The Hydrogen Electrode in pH Measurements
2.3	Optical pH Measurement Technology
2.4	pH Standard Solutions and Traceability
2.4.1	Primary pH Standards
2.4.2	Secondary pH Standards
3	Electrode Cell and Electrode Architecture
3.1	Principal Types of pH Electrodes
3.2	Glass Electrodes
3.3	Reference Electrodes
3.4	Liquid Junction
3.5	Combined Electrodes
3.6	Testing Glass Electrodes
3.7	Alternative pH Electrodes
4	pH Signal Processing
4.1	Potential Input Amplifier
4.2	pH Calculation and Correction Functions
4.3	pH meters and Transmitters: Data Visualization and Output
4.4	Testing and Input Calibration of pH Meters and Transmitters
4.5	Digitalization of pH Sensors and Sensor Self-diagnostics
5	pH Measurement Requirements in Different Industries
5.1	pH Measurement in the Pharmaceutical Industry
5.2	pH Measurement in the Food and Beverage Industry
5.3	pH Measurements in the Chemical Industry
5.3.1	pH Measurement in Concentrated Solutions
5.3.2	Suspension Effects
5.3.3	pH Measurement in Nonaqueous Solvents
5.3.4	Extreme Temperature
5.3.5	Interfering Compounds
6	Good Practices in Laboratory pH Measurement
6.1	Evaluation and Selection
6.1.1	Selection of a pH Meter
6.1.2	Selection of a pH Electrode
6.1.3	Selection of pH Buffer Solutions
6.1.4	Selection of PC Software and Additional Accessories
6.2	Installation and Qualification
6.3	Routine Operation
6.3.1	Sensor Calibration and Verification
6.3.2	Sensor Care and Maintenance
6.3.3	Buffer Quality
6.3.4	Meter Settings
6.4	Product Retirement
7	Process pH Measurement
7.1	Off-Line, At-Line, and Inline Measurements
7.2	Inline pH Sensor Calibration under Process Conditions
8	Inline Installations
8.1	Immersion Assemblies
8.2	Built-In Static Assemblies
8.3	Retractable Assemblies
8.4	Flow-Through Assemblies
9	pH Signal Integration
9.1	Analog Signal Integration
9.2	Digital Signal Integration
10	pH Control
	References

References

1 Van den Berg , L. ( 1960 ) pH Measurement at Low Temperatures Using Modified Calomel and Glass Electrodes , Anal. Chem. 32 , 628 – 631 .
10.1021/ac60162a016
CAS Web of Science® Google Scholar
2 Buck , R.P. , Rondinini , S. , Covington , A.K. , et al. ( 2002 ) Measurement of pH. Definition, Standards, and Procedures, (IUPAC Recommendations 2002) , Pure Appl. Chem. 74 , 2169 – 2200 .
10.1351/pac200274112169
CAS Web of Science® Google Scholar
3 Galster , H. ( 1991 ) pH-Measurement, Fundamentals, Methods, Applications, Instrumentation , VCH Verlagsgesellschaft , Weinheim .
Google Scholar
4 Muller , P. ( 1994 ) Glossary of Terms Used in Physical Organic Chemistry (IUPAC Recommendations 1994) , Pure Appl. Chem. 66 ( 5 ), 1077 – 1184 .
10.1351/pac199466051077
Web of Science® Google Scholar
5 DIN , ( 2012 ) DIN 19267, pH Messung – Technische Pufferlösungen, vorzugsweise zur Kalibrierung und Justierung von technischen pH-Messeinrichtungen.
Google Scholar
6 Robinson , R.A. and Stokes , R.H. ( 1959 ) Electrolyte Solutions , Butterworths , London , pp. 450 – 503 .
Google Scholar
7 Debye , P. and Hückel , E. ( 1923 ) Zur Theorie der Elektrolyte , Phys. Z. 24 , 185 – 206 .
CAS Web of Science® Google Scholar
8 Bates , R.G. ( 1965 ) Determination of pH , J. Wiley & Sons , New York .
Google Scholar
9 Manov , G.G. , Bates , R.G. , Hamer , W.J. and Acree , S.F. ( 1943 ) Values of the Constants in the Debye-Hückel Equation for Activity Coefficients , J. Am. Chem. Soc. 65 , 1765 – 1767 .
10.1021/ja01249a028
CAS Google Scholar
10 Kielland , J. ( 1937 ) Individual Activity Coefficients of Ions in Aqueous Solutions , J. Am. Chem. Soc. 59 , 1675 – 1678 .
10.1021/ja01288a032
CAS Web of Science® Google Scholar
11 Schwabe , K. ( 1974 ) Physikalische Chemie , vol. 2, Akademie Verlag , Berlin p. 65.
Google Scholar
12 Bates , R.G. and Guggenheim , E.A. ( 1960 ) Report on the Standardisation of pH and Related Terminology , Pure Appl. Chem. 1 , 163 – 169 .
10.1351/pac196001010163
CAS Google Scholar
13 Eigen , M. ( 1968 ) die ‘unmessbar’ schnellen Reaktionen , Angew. Chem. 80 , 892 – 906 .
10.1002/ange.19680802105
Google Scholar
14 Bingold , G.J. , Brewer , A.D. and Heam , B. ( 1971 ) Specific Conductivity and Ionic Product of Water Between 50 and 271 °C , Trans. Faraday Soc. 67 , 2419 – 2430 .
10.1039/tf9716702419
Web of Science® Google Scholar
15 Mussini , T. and Mazza , F. ( 1986 ) Comparison of Different pH Scales, Discussion Contribution , DECHEMA Monogr. 101 , 79 – 82 .
Google Scholar
16 Rondinini , S. , Longhi , P. and Mussini , P.R. ( 1987 ) Autoprotolysis Constants in Non Aqueous Solvents and Aqueous Organic Solvent Mixtures , Pure Appl. Chem. 59 , 1692 – 1702 .
10.1351/pac198759121693
Web of Science® Google Scholar
17 Owen , B.B. ( 1932 ) Direct Measurements of the Primary, Secondary and Total Medium Effects in Acetic Acid , J. Am. Chem. Soc. 54 , 1758 – 1769 .
10.1021/ja01344a006
CAS Google Scholar
18 IEC ( 1982 ) IEC 746–2, Expression of Performance of Electro Chemical Analyzers, Part 2: pH Value , Bureau Central de la Commission Electrotechnique Internationale , Genève .
Google Scholar
19 Graham , D.J. , Jaselskis , B. and Moore , C.E. ( 2013 ) Development of the Glass Electrode and the pH Response , J. Chem. Educ. 90 , 345 – 351 .
10.1021/ed300246x
CAS Web of Science® Google Scholar
20 Covington , A.K. ( 1985 ) Procedures for Testing pH Responsive Glass Electrodes at 25, 37, 65 and 85 C and Determination of Alkaline Errors up to 1 mol dm ⁻³ Na ⁺ , K ⁺ , Li ⁺ , Pure Appl. Chem. 57 ( 6 ), 887 – 898 .
10.1351/pac198557060887
Web of Science® Google Scholar
21 Jerkiewicz , J. ( 2020 ) Standard and Reversible Hydrogen Electrodes: Theory, Design, Operation, and Applications , ACS Catal. 10 , 8409 – 8417 .
10.1021/acscatal.0c02046
CAS Web of Science® Google Scholar
22 Spitzer , P. and Pratt , K.W. ( 2011 ) The History and Development of a Rigorous Metrological Basis for pH Measurements , J. Solid State Electrochem. 15 , 69 – 76 .
10.1007/s10008-010-1106-9
CAS Web of Science® Google Scholar
23 Steinegger , A. , Wolfbeis , O.S. and Borisov , S.M. ( 2020 ) Optical Sensing and Imaging of pH Values: Spectroscopies, Materials, and Applications , Chem. Rev. 120 , 12357 – 12489 .
10.1021/acs.chemrev.0c00451
CAS PubMed Web of Science® Google Scholar
24 Alkurashi , Y. , Elsherif , M. , Hendi , A. , et al. ( 2022 ) Optical Hydrogel Detector for pH Measurements , Biosensors 12 , 40 – 48 .
10.3390/bios12010040
PubMed Google Scholar
25 Indzédy , J. , Lengyel , T. and Ure , A.M. ( 1997 ) IUPAC Compendium of Analytical Nomenclature Definitive Rules , 3rd edn, Blackwell Scientific Publ. , Oxford .
Google Scholar
26 Spitzer , P. ( 1997 ) Comparison of pH Values of Primary Buffer Materials, PTB-W-68 , PTB-Bericht , Braunschweig .
Google Scholar
27 DIN , ( 2015 ) DIN 19266, pH Messung – Referenzpufferlösungen zur Kalibrierung von pH-Messeinrichtungen.
Google Scholar
28 Bates , R.G. , Paalo , M. and Robinson , R.A. ( 1963 ) Interpretation of pH-Measurements in Alcohol – Water Solvents , J. Phys. Chem. 67 , 1833 – 1183 .
10.1021/j100803a022
CAS Web of Science® Google Scholar
29 Oesch , U. , Ammann , D. , Brzózka , Z. , et al. ( 1986 ) Design of Neutral Hydrogen Ion Carriers for Solvent Polymeric Membrane Electrodes of Selected pH Range , Anal. Chem. 58 , 2285 – 2289 .
10.1021/ac00124a037
CAS Web of Science® Google Scholar
30 Lahav , M. , Katz , E. and Willner , I. ( 1998 ) A Covalently Linked Quinone-ferrocene Monolayer-electrode: A pH Sensor with an Internal Reference , Electroanalysis 10 , 1159 – 1162 .
10.1002/(SICI)1521-4109(199811)10:17<1159::AID-ELAN1159>3.0.CO;2-L
CAS Web of Science® Google Scholar
31 Shiu , K.K. , Song , F. and Dai , H.P. ( 1996 ) Potentiometric pH Sensor with Anthraquinonesulfonate Adsorbed on Glassy Carbon Electrodes , Electroanalysis 8 , 1160 – 1164 .
10.1002/elan.1140081217
CAS Web of Science® Google Scholar
32 Srinivas , S. , Ashokkumar , K. , Sriraghavan , K. and Kumar , A.S. ( 2021 ) A Prototype Device of Microliter Volume Voltammetric pH Sensor Based on Carbazole–quinone Redox Probe Tethered MWCNT Modified Three in One Screen Printed Electrode , Sci. Rep. 11 , 13905 – 13916 .
10.1038/s41598-021-93368-5
CAS PubMed Web of Science® Google Scholar
33 Voorthuyzen , J.A. and Bergveld , P. ( 1990 ) Photoelectric Effects in Ta ₂ O ₅ –SiO ₂ –Si structures , Sensors Actuators B Chem. 1 , 350 – 353 .
10.1016/0925-4005(90)80228-R
CAS Web of Science® Google Scholar
34 Chin , Y.-L. , Chou , J.-C. , Sun , T.-P. , et al. ( 2001 ) A Novel SnO ₂ /Al Discrete Gate ISFET pH Sensor with CMOS Standard Process , Sens. Actuators 75 , 36 – 42 .
10.1016/S0925-4005(00)00739-5
CAS Web of Science® Google Scholar
35 Cremer , M. ( 1906 ) Cremer's Electrode , Z. Biol. 47 , 562 .
CAS Google Scholar
36 Chung , D.D.L. ( 2020 ) Materials for Electromagnetic Interference Shielding , Mater. Chem. Phys. 255 , 123587 .
10.1016/j.matchemphys.2020.123587
CAS Web of Science® Google Scholar
37 Haber , F. and Klemenziewicz , Z. ( 1909 ) Uber elektrische Phasengrenzkrafte , Z. Phys. Chem. 67 , 385 – 431 .
10.1515/zpch-1909-6720
CAS Web of Science® Google Scholar
38 Hubbard , D. ( 1946 ) Hygroscopicity and Electrode Function (pH Responsive) of Glasses as a Measure of Service Ability , J. Res. NBS 36 , 511 – 520 .
CAS Web of Science® Google Scholar
39 Bach , H. and Baucke , F.G.K. ( 1982 ) Investigations of Glasses Using Surface Profiling by Spectrochemical Analysis of Sputter-induced Radiation I. Surface Profiling Technique with high In-Depth Resolution , J. Am. Chem. Soc. 65 , 527 – 533 .
10.1111/j.1151-2916.1982.tb10776.x
CAS Web of Science® Google Scholar
40 Schwabe , K. and Dahms , H. ( 1959 ) Versuche zur Frage der Durchlässigkeit von Glaselektroden für Wasserstoffionen mit Hilfe von Tritium Markierung , Monatsber. Dtsch. Akad. Wiss. 1 , 279 – 282 .
CAS Google Scholar
41 Scholze , H. ( 1991 ) Glass. Nature, Structure, and Properties , Springer Verlag , New York .
Google Scholar
42 Belyustin , A.A. ( 2011 ) The Centenary of Glass Electrode: From Max Cremer to F. G. K. Baucke , J. Solid State Electrochem. 15 , 47 – 65 .
10.1007/s10008-010-1105-x
CAS Web of Science® Google Scholar
43 Baucke , F.G.K. ( 2009 ) The Glass Electrode 100th Anniversary, 25 Years of Understanding How it Functions , Chem. Anal. (Warsaw, Pol.) 54 , 1109 – 1120 .
CAS Google Scholar
44 MacInnes , D.A. and Dole , M. ( 1930 ) The Behavior of Glass Electrodes of Different Compositions , J. Am. Chem. Soc. 52 , 29 – 36 .
10.1021/ja01364a005
CAS Web of Science® Google Scholar
45 Perley , G.A. ( 1949 ) Glasses for Measurement of pH , Anal. Chem. 21 , 394 – 401 .
10.1021/ac60027a013
CAS Web of Science® Google Scholar
46 Baucke , F.G.K. ( 1975 ) Standardpotentiale ( ϵ ^0' + ϵ _j ) _T der Silber/Silberchlorid-Elektrode in 3.5 M und ges. KCl unter Verwendung entsprechender (“Cl-ionenselektiver”) Membranelektroden (0–95°C) , Chem. Ing. Tech. 47 , 565 – 566 .
10.1002/cite.330471306
CAS Web of Science® Google Scholar
47 Galster , H. ( 1979 ) Natur, Messung und Anwendung der Redoxspannung, Teil I , Chem. Lab. Betr. (CLB) 30 , 330 – 335 .
CAS Google Scholar
48 Ito , S. , Hachiya , H. , Baba , K. , et al. ( 1995 ) Improvement of the silver/silver chloride reference electrode and its application to pH measurement , Talanta 42 , 1685 – 1690 .
10.1016/0039-9140(95)01628-7
CAS PubMed Web of Science® Google Scholar
49 Cammann , K. and Galster , H. ( 1996 ) Das Arbeiten mit ionenselektiven Elektroden , 3rd edn, Springer Verlag , Berlin .
10.1007/978-3-642-61408-8
Google Scholar
50 Hamann , C.H. and Vielstich , W. ( 1998 ) Elektrochemie I , Wiley-VCH Verlag , Weinheim .
Google Scholar
51 Wilczek-Vera , G. , Rodil , E. and Vera , J.H. ( 2004 ) On the Activity of Ions and the Junction Potential: Revised Values for all Data , Thermodynamics 50 , 445 – 462 .
CAS Google Scholar
52 Mousavi , M.P.S. , Saba , S.A. , Anderson , E.L. , et al. ( 2016 ) Avoiding Errors in Electrochemical Measurements: Effect of Frit Material on the Performance of Reference Electrodes with Porous Frit Junctions , Anal. Chem. 88 , 8706 – 8713 .
10.1021/acs.analchem.6b02025
CAS PubMed Web of Science® Google Scholar
53 Ito , S. , Kobayashi , F. , Baba , K. , et al. ( 1996 ) Development of Long-term Stable Reference Electrode with Fluoric Resin Liquid Junction , Talanta 43 , 135 – 142 .
10.1016/0039-9140(95)01723-2
CAS PubMed Web of Science® Google Scholar
54 Pedrotti , J.J. , Agnes , L. and Gutz , I.G.R. ( 1996 ) Miniaturized Reference Electrodes with Microporous Polymer Junctions , Electroanalysis 8 , 673 – 675 .
10.1002/elan.1140080713
Web of Science® Google Scholar
55 Coetzee , J.F. and Gardner , C.W. ( 1982 ) Exchange Current Densities and Other Properties of Reference Electrodes Based on the Triiodide Iodide and Silver(I) Ion-silver Couples in Organic Solvents , Anal. Chem. 54 ( 14 ), 2530 – 2532 .
10.1021/ac00251a027
CAS Web of Science® Google Scholar
56 Dohner , R. , Wegmann , D. , Morf , M.E. and Simon , W. ( 1986 ) Reference Electrode with Free-flowing Free-diffusion Liquid Junction , Anal. Chem. 2585 – 2589 .
10.1021/ac00125a053
Web of Science® Google Scholar
57 Bühler H. and Galster H. ( 1985 ) Proton AG, DE 3 405 401 C2.
Google Scholar
58 DIN , ( 1989 ) DIN 19263 pH Messung, Glaselektroden.
Google Scholar
59 Michael Krebs , W. ( 1972 ) Instrument for the Direct Measurement of the Resistance of glass pH Electrodes , Anal. Chem. 44 ( 1 ), 187 – 190 .
10.1021/ac60309a024
Web of Science® Google Scholar
60 Mettler-Toledo , A.G. , Greifensee , C.H. ( 2009 ). US Patent Application, Pub. date 18.06.2009. US2009/0157338A1 (C. Wang).
Google Scholar
61 Lindner , E. , Toth , K. and Pungor , E. ( 1986 ) Definition and Determination of Response Time of Ion Selective Electrodes , Pure Appl. Chem. 58 ( 3 ), 469 – 479 .
10.1351/pac198658030469
CAS Web of Science® Google Scholar
62 Frankaer , C.G. and Sorensen , T.J. ( 2019 ) Investigating the Time Response of an Optical pH Sensor Based on a Polysiloxane–Polyethylene Glycol Composite Material Impregnated with a pH-Responsive Triangulenium Dye , ACS Omega 4 , 8381 – 8389 .
10.1021/acsomega.9b00795
CAS PubMed Web of Science® Google Scholar
63 Munro , W.A. , Thomas , C.L.P. , Simpson , I. , et al. ( 1996 ) Deterioration of pH Electrode Response Due to Biofilm Formation on the Glass Membrane , Sensors Actuators B 37 , 187 – 194 .
10.1016/S0925-4005(97)80137-2
CAS Web of Science® Google Scholar
64 Kurzweil , P. ( 2009 ) Metal Oxides and Ion-Exchanging Surfaces as pH Sensors in Liquids: State-of-the-Art and Outlook , Sensors 9 , 4955 – 4985 .
10.3390/s90604955
CAS PubMed Web of Science® Google Scholar
65 Caspers , F. , Kroyer , T. and Wendel , J.C. ( 2009 ) Comparison of enamel and stainless steel electron cloud clearing electrodes tested in the CERN proton synchrotron . Proceedings of PAC09, Vancouver, BC, Canada.
Google Scholar
66 Emmerich , B. ( 1978 ) Die Emailelektrode, eine neue Lösung zur pH-Messung im Betrieb , Regelungstech. Prax. 20 , 313 – 317 .
Google Scholar
67 Kolthoff , I.M. and Hartong , B.D. ( 1925 ) On the Antimony Electrode , Recl. Trav. Chim. 44 , 113 – 120 .
10.1002/recl.19250440205
CAS Google Scholar
68 Schwabe , K. ( 1951 ) Die Wismutelektrode zur pH-Indikation , Z. Elektrochem. 55 , 411 .
10.1002/bbpc.19510550513
CAS Web of Science® Google Scholar
69 Manjakkal , L. , Szwagierczak , D. and Dahiya , R. ( 2020 ) Metal Oxides Based Electrochemical pH Sensors: Current Progress and Future Perspectives , Progr. Mater. Sci. 109 , 100635 .
10.1016/j.pmatsci.2019.100635
CAS Web of Science® Google Scholar
70 Monteiro , M.C.P. and Koper , M.T.M. ( 2021 ) Measuring Local pH in Electrochemistry , Curr. Opin. Electrochem. 25 , 100649 .
10.1016/j.coelec.2020.100649
CAS Web of Science® Google Scholar
71 Ravichandran , S. , Thiagarajan , C. and Kumar , P.S. ( 2021 ) pH Sensitivity Estimation in Potentiometric Metal Oxide pH Sensors Using the Principle of Invariance , Hindawi Int. J. Chem. Eng. 2021 , 1 – 18 .
10.1155/2021/5551259
Web of Science® Google Scholar
72 Vonau , W. and Guth , U. ( 2006 ) pH Monitoring: A Review , J. Solid State Electrochem. 10 , 746 – 752 .
10.1007/s10008-006-0120-4
CAS Web of Science® Google Scholar
73 Katsube , T. , Lauks , I. and Zemel , J.N. ( 1981 ) pH-sensitive Sputtered Iridium Oxide Films , Sens. Actuators 2 , 399 – 410 .
10.1016/0250-6874(81)80060-1
Web of Science® Google Scholar
74 DIN , ( 1994 ) DIN 19265, pH-Messung, pH-Messumformer, Anforderungen.
Google Scholar
75 Micic , L. and Gilly , A. ( 1963 ) Gleichspannungsverstärker mit Kapazitätsdioden für kleine Eingangsleitungen , Electronics 12 , 263 – 265 .
Google Scholar
76 Rosemount Analytical Inc ., ( 1995 ) CA2187425A1 (B. La Rocca, G. T. O'Brien).
Google Scholar
77 Conducta Endress & Hauser , ( 2002 ) DE10218606A1 (T. Pechstein, H. Straub, D. Wittmer, D. Steinmüller).
Google Scholar
78 Yokogawa Electric Corp ., ( 1988 ) US4777444A (J. M. Beijk, T. Both).
Google Scholar
79 Rosemount Analytical Inc ., ( 1991 ) US5268852A (T. J. Forsythe, R. Koluvek).
Google Scholar
80 USP , ( 2017 ) USP 41 Physical Tests and Determinations <791> pH.
Google Scholar
81 European Pharmacopoeia , ( 2019 ) European Pharmacopoeia 10.0, Method of analysis – Potentiometric determination of pH 2.2.3.
Google Scholar
82 Japanese Pharmacopoeia , ( 2016 ) Japanese Pharmacopoeia 17th Edition, General tests, 2.54 pH determination.
Google Scholar
83 Code of Federal Regulations , ( 2021 ) Code of Federal Regulations. 21, part 11—Electronic Records; Electronic Signatures.
Google Scholar
84 EudraLex , ( 2011 ) EudraLex Volume 4 Annex 11—Computerised Systems.
Google Scholar
85 Code of Federal Regulations , ( 2008 ) Code of Federal Regulations. 21, part 211—Current Good Manufacturing Processes for Finished Pharmaceuticals.
Google Scholar
86 Baloda , S. , Martin , J. , Carter , J. , et al. ( 2008 ) Guide to Irradiation and Sterilization Validation of Single Use Bioprocess Systems , Bioprocess Int.
Google Scholar
87 ISO , ( 2010 ) ISO 26462:2010 Milk—Determination of lactose content—Enzymatic method using difference in pH.
Google Scholar
88 ISO , ( 2010 ) ISO 5546:2010 Caseins and caseinates—Determination of pH (Reference method).
Google Scholar
89 ISO , ( 2004 ) ISO 7238:2004 Butter—Determination of pH of the serum—Potentiometric method.
Google Scholar
90 AOAC , ( 1999 ) AOAC Official Method 960.19, pH of Wines. 16th edn.
Google Scholar
91 Code of Federal Regulations , ( 2011 ) Juice HACCP Rule (Code of Federal Regulations) 21 CFR part 120.
Google Scholar
92 Code of Federal Regulations , ( 2011 ) Code of Federal Regulations. 21, part 146—Canned fruit juices. U.S. Printing Office, Washington, DC.
Google Scholar
93 Guyot-Declerck , C. , François , N. , Ritter , C. , et al. ( 2005 ) Influence of pH and Ageing on Beer Organoleptic Properties. A Sensory Analysis Based on AEDA Data , Food Quality Preference 16 ( 2 ), 157 – 162 .
10.1016/j.foodqual.2004.04.007
Web of Science® Google Scholar
94 D. Steen and P.R. Ashurst eds. ( 2008 ) Carbonated Soft Drinks: Formulation and Manufacture , J.Wiley & Sons .
Google Scholar
95 FDA ( 1997 ) HACCP Principles & Application Guidelines , FDA .
Google Scholar
96 Code of Federal Regulations , ( 2021 ) Code of Federal Regulations. 21 part 114—Acidified Foods.
Google Scholar
97 Landry , W.L. , Schwab , A.H. and Lancette , G.A. ( 1998 ) Examination of Canned Foods , in Bacteriological Analytical Manual , 8th edn, AOAC International , Gaithersburg, MD , Revision A, Chapter 21A.
Google Scholar
98 ISO , ( 2018 ) ISO 22000:2018 Food Safety Management Systems.
Google Scholar
99 Laing , H. , Bull , S. , Joyce , S. and O'Malley , C. ( 2021 ) Investigating Cleaning in Place (CIP) Chemical, Water, and Energy Use: A Comparative Study of Standard Operating Procedure (SOP) for UK North East Microbreweries , J. Brewing Distilling 10 ( 1 ), 17 – 28 .
10.5897/JBD2021.0055
Google Scholar
100 Clarke , M.A. ( 1970 ) The Effect of Solution Structure on Electrode Processes in Sugar Solutions. Proc. of the 1970 Technical Session on Cane Sugar Refining Res., pp. 179–188.
Google Scholar
101 Emmerich , A. and Reichel , C. ( 1961 ) Über die pH-Bestimmung in Rübenzucker , Zucker 14 , 340 – 343 .
CAS Google Scholar
102 Schwabe , K. ( 1967 ) Azidität konzentrierter Electrolytlösungen , Electrochim. Acta 12 , 67 – 93 .
10.1016/0013-4686(67)85007-2
CAS Web of Science® Google Scholar
103 Schwabe , K. ( 1960 ) Elektrochemische pH-Messung unter extremen Bedingungen , Monogr. zu Angew. Chem. And Chem. Ing. Tech., Verlag Chemie , Weinheim , pp. 26 – 29 .
Google Scholar
104 Bach , H. , Baucke , F.G.K. and Krause , D. ( 2001 ) Electrochemistry of Glasses and Glass Melts, Including Glass Electrodes , Springer Verlag , Berlin .
10.1007/978-3-662-04486-5
Google Scholar
105 Licht , S. ( 1985 ) pH Measurement in Concentrated Alkaline Solutions , Anal. Chem. 57 , 514 – 519 .
10.1021/ac50001a045
CAS Web of Science® Google Scholar
106 Wiegner , G. ( 1930 ) Über Wasserstoff- und Hydroxylionen in Ionenschwärmen um suspendierte Teilchen und suspendierte Ultramikronen , Kolloid Z. 51 , 49 – 60 .
10.1007/BF01474479
CAS Google Scholar
107 Pallmann , H. ( 1930 ) Die Wasserstoffaktivität in Suspensionen und kolloiddispersen Systemen , Kolloidchem. Beih. 30 , 334 – 405 .
10.1007/BF02555304
Google Scholar
108 Milicka , L. ( 1972 ) Zum Problem der pH-Messung in Suspensionen , Z. Phys. Chem. 249 , 63–72, 117–180.
Google Scholar
109 Jenney , H. , Nielsen , T.R. , Coleman , N.T. and Williams , D.E. ( 1950 ) Concerning the Measurement of pH, Ion Activities and Membrane Potentials in Colloidal System , Science 112 , 164 – 167 .
10.1126/science.112.2902.164
PubMed Web of Science® Google Scholar
110 Brezinski , D.P. ( 1983 ) Influence of Colloidal Charge on Response of pH and Reference Electrodes: The Suspension Effect , Talanta 30 , 347 – 354 .
10.1016/0039-9140(83)80078-2
CAS PubMed Web of Science® Google Scholar
111 Spiegel , K. and Möhler , W. ( 1992 ) pH Messung in der Verfahrenstechnik , DECHEMA Monogr. 126 , 373 – 388 .
CAS Google Scholar
112 Cruse , K. ( 1956 ) pH-Begriff und pH-Messung in wasserfreien Lösungen , Arch. Tech. Mess. 125–128, 169–172, 203–204, 217–220.
10.1524/teme.1956.240251.jg.239
Google Scholar
113 Mussini , T. , Covington , A.K. , Longhi , P. and Rondini , S. ( 1985 ) Criteria of Standardisation of pH Measurements in Organic Solvents and Water-Organic Solvent Mixtures of Moderate to High Permittives , Pure Appl. Chem. 57 , 865 – 876 .
10.1351/pac198557060865
Web of Science® Google Scholar
114 Midgley , D. ( 1990 ) A Review of pH Measurement at High Temperatures , Talanta 37 , 767 – 781 .
10.1016/0039-9140(90)80118-Y
CAS PubMed Web of Science® Google Scholar
115 Hettiarachchi , S. , Makela , K. , Song , H. and MacDonald , D.D. ( 1992 ) The Viability of pH Measurements in Supercritical Aqueous Systems , J. Electrochem. Soc. 139 , L3 – L4 .
10.1149/1.2069213
CAS Web of Science® Google Scholar
116 Schwabe , K. ( 1976 ) pH Messtechnik , Th. Steinkopf , Dresden .
Google Scholar
117 ISO , (2015) ISO 9001, Quality Management Systems—Requirements.
Google Scholar
118 ISO , ( 2005 ) ISO/IEC 17025, General Requirements for the Competence of Testing and Calibration Laboratories.
Google Scholar
119 The American Association for Laboratory Accreditation , ( 2008 ) P102 – A2LA Policy on Measurement Traceability.
Google Scholar
120 FDA (Food and Drug Administration) , ( 2016 ) Draft Guidance for Industry Data Integrity and Compliance with cGMP , Silver Spring , MD, USA .
Google Scholar
121 WHO ( 2016 ) WHO Technical Report Series No. 996 Annex 5 Guidance on Good Data and Records Management Practices , World Health Organization , Geneva .
Google Scholar
122 Ellison , S. and Williams , A. ( 2012 ) Quantifying Uncertainty in Analytical Measurement.
Google Scholar
123 United States Pharmacopeia , ( 2018 ) Chapter, General. <1058>“Analytical Instrument Qualification” USP 41: NF 36.
Google Scholar
124 METTLER TOLEDO , ( 2016 ) A Guide to pH Measurement—The Theory of Laboratory pH Applications.
Google Scholar
125 Ingold AG , ( 1990 ) CH 673 783 (U. Schaad, J. Brinkmann).
Google Scholar
126 WTW , ( 1986 ) DE 3 518 870 A1 (G. Gugel).
Google Scholar
127 Berliner Entwaesserungswerke , ( 1987 ) Bericht: FEV Wasser 102 04 318 Teilvorhaben pH-Wert.
Google Scholar
128 Siemens AG , ( 1974 ) DE 1 804 962 (E. Michel, K.H. Papst).
Google Scholar
129 Proton AG , ( 1972 ) DE 2 061 978 (W. Ingold).
Google Scholar
130 Früh , K.F. , Schaudel , D. , Urbas , L. and Tauchnitz , T. ( 2018 ) Handbuch der Prozessautomatisierung Prozessleittechnik für verfahrenstechnische Anlagen , 6th edn, DIV Deutscher Industrieverlag .
Google Scholar
131 Rosemount Inc. , ( 1998 ) EP0852701A1 (M.J. Smith, G.C. Hausler).
Google Scholar
132 Conducta Endress & Hauser , ( 2005 ) EP1495381A1 (M. Gunzert, D. Wittmer).
Google Scholar
133 Conducta Endress & Hauser , ( 2010 ) EP2198353A2 (S. Buschnakowski, T. Mieth, S.-M. Scheibe).
Google Scholar
134 Fisher Rosemount Systems Inc. , ( 2020 ) US202017017094A (M.J. Nixon, G.K. Law).
Google Scholar
135 Holowczak , R. and Furey , J. ( 2020 ) Challenges and Benefits of Networking Process Control Manufacturing Systems - Integration to Business Systems in Industry 4.0 , BioProcess Int. 18 , 17 – 20 .
Google Scholar
136 Kubli , H. ( 1967 ) Ein einfaches Präzisions-pH-Regelsystem für die mikrobiologische Verfahrenstechnik , Int. Jahrb. Chem. Ind. 3 – 4 .
Google Scholar
137 Bingi , K. , Ibrahim , R. , Karsiti , M.N. , Chung , T.D. , and Hassan , S.M. ( 2016 ) Optimal PID control of pH neutralization plant , 2016 2nd IEEE International Symposium on Robotics and Manufacturing Automation (ROMA) , pp. 1–6.
Google Scholar
138 Samal , E. ( 1957 ) Verbesserung der Regeltüte durch Störgrößenaufschaltung , Regelungstech 5 , pp. 40–45, 154–158.
Google Scholar
139 Samal , E. ( 1957 ) Verbesserung der Regeltüte durch Verwendung von Hilfsgrößenbeeinflussung oder Reihenschaltung mehrerer Regler , Regelungstech 5 , 192 – 198 .
Google Scholar

pH Measurement and Control

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pH Measurement and Control

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