Handbook of Acid-Base Indicators (pH Indicators)

The second edition of Handbook of Acid-Base Indicators (pH Indicators) has been revised, enlarged and updated with several recent references and added 53 new acid-base indicators.

Dr. R. W. Sabnis is an accomplished Intellectual Property Manager at Arclin USA LLC, where he oversees the company's global patent portfolio and collaborates with outside counsel on trademark matters. He drafts and prosecutes U.S. and PCT international patent applications, engages closely with inventors and examiners, and supports merger and acquisition activities through in-depth patent portfolio reviews. With more than 35 years of combined technical and legal experience following his Ph.D., Dr. Sabnis brings a rare dual expertise that bridges industrial research and development (over 16 years) and patent law practice (over 19 years) across both law firm and corporate environments. His professional interests span a broad spectrum of scientific and technological disciplines, including dyes and pigments, organic and medicinal chemistry, heterocycles, polymers, coatings, material science, synthesis, formulations, and patents. Dr. Sabnis has held prior roles with leading corporations and law firms, including GeorgiäPacific LLC, Pfizer Inc., Squire Patton Boggs LLP, and Smith Gambrell Russell LLP, where he drafted and prosecuted high-value patent applications. His scientific career is equally distinguished, marked by 500+ publications, including 3 books. Born and raised in Mumbai, India, Dr. Sabnis earned his M.Sc. in Organic Chemistry from the University of Mumbai and his Ph.D. in Organic Chemistry (Dyes) from the Institute of Chemical Technology (ICT, formerly UDCT), Mumbai. He is a Chartered Colorist, a Fellow of the Society of Dyers and Colourists (CCol FSDC), and a Fellow of the Royal Society of Chemistry (FRSC). Internationally recognized as one of the foremost authorities on dye chemistry, Dr. Sabnis is credited with inventing the world's first non-staining colored bubbles and a color-changing dye system with wide-ranging commercial and scientific applications. Over the past four decades, he has made significant contributions to color science, advancing dyes for biomedical, personal care, cosmetic, electronic (display/OLED), ink, paint, plastic, textile, and toy applications. Dr. Sabnis is a prolific author and inventor with over 500 publications, including books, book chapters, encyclopedia entries, reviews, patents, journal papers and symposia papers. He is an inventor on numerous U.S. Patents and PCT international applications and has received several prestigious honors such as the Perkin Innovation Award, Pfish Award, Grand Innovation Award, Competitive Spirit Award, and Best Doctoral Thesis Award. The Society of Dyers and Colourists (Bradford, U.K.) has recognized him with the Gold Medal for Outstanding Service to the Coloration Industry and the Centenary Medal for Best Review in Coloration Technology. He has also received the UAA-ICT Distinguished Alumnus Award - Research from his alma mater, the Institute of Chemical Technology (ICT). He has been recognized for both professional excellence and community impact. He has been honored with USPTO Patent Pro Bono Achievement Certificates (2021-2025) and has represented approximately 400 patent matters, including U.S. Patents and PCT international applications. The American Chemical Society (ACS) has awarded him Certificates of Appreciation for his exceptional service to the U.S. National Chemistry Olympiad (USNCO) (2023-2025). He has also been bestowed with 2025 Outreach Volunteer of the Year Award by the American Chemical Society (2025). Further, he serves as an ACS Patent Panelist for ACS Medicinal Chemistry Letters and as an Advisory Board member for Georgia Patents. In addition to his legal practice, Dr. Sabnis is deeply committed to education. He serves as an Adjunct Professor at the Institute of Chemical Technology (ICT), Mumbai (2019-Present) and was an Adjunct Assistant Professor at the University of Missouri, Rolla (1999-2004). With a career that bridges science, law, and education, Dr. Sabnis exemplifies the role of a modern intellectual property leader. His multidisciplinary expertise, combined with a deep commitment to innovation, mentorship, and public service, continues to shape the advancement of both industry and academia. Dr. Sabnis is the author of three authoritative reference works on color chemistry: Handbook of Fluorescent Dyes and Probes, Handbook of Biological Dyes and Stains, and Handbook of Acid-Base Indicators. He continues to pursue his lifelong passion for the chemistry of color while advancing innovation at the intersection of science and intellectual property.

1. Acid Alizarin Violet N 2. Acid Blue 89 3. Acid Blue 92 4. Acid Fuchsin 5. Acridine 6. Alizarin (Alizarin Red) 7. Alizarin Red S 8. Alizarin Yellow GG 9. 10. Alkali Blue 11. 9-Amino-6-chloro-2-methoxyacridine (ACMA) 12. 5-Aminosalicylic acid 13. Anilinesulfonephthalein 14. Anthranilic acid 15. Aurin 16. Benzaurin 17. Benzopurpurin 4B 18. Benzoyl Auramine G 19. 20. Brilliant Green 21. Brilliant Yellow 22. Bromochlorophenol Blue 23. Bromochlorophenol Blue, Sodium Salt 24. Bromocresol Green 25. Bromocresol Green, Sodium Salt 26. Bromocresol Purple 27. Bromocresol Purple, Sodium Salt 28. Bromophenol Blue 29. Bromophenol Blue, Sodium Salt 30. p-Bromophenolmalein 31. Bromophenol Red 32. 33. Bromothymol Blue 34. Bromothymol Blue, Sodium Salt 35. Bromoxylenol Blue 36. Butyl Orange 37. Butyl Orange, Potassium Salt 38. Butyl Orange, Sodium Salt 39. Butyl Red 40. Calcein 41. Calmagite 42. Carbazol Yellow 43. 5-Carboxyfluorescein 44. 6-Carboxyfluorescein 45. 5-Carboxyfluorescein diacetate 46. 6-Carboxyfluorescein diacetate 47. 5-Carboxynaphthofluorescein 48. 6-Carboxynaphthofluorescein 49 Carminic acid 50. Carvacrolphthalein 51. Chlorocresol Green 52. 53. Chlorophenol Red 54. Chlorophenol Red, Sodium Salt 55. Chrome Orange GR 56. Chrysoidin 57. Clayton Yellow 58. Congo Red 59. Coumarin 60. o-Cresolbenzein 61. o-Cresolphthalein 62. o-Cresolphthalein complexon 63. m-Cresol Purple 64. m-Cresol Purple, Sodium Salt 65. o-Cresol Red 66. o-Cresol Red, Sodium Salt 67. Crystal Violet 68. Curcumin 69. 70. Dibromo-o-cresolbenzein 71. Dibromothymolbenzein 72. 73. 6,7-Dihydroxycoumarin 74. 3,6-Dihydroxyphthalimide 75. Diiodophenolsulfonephthalein) 76. 4-(N,N-Dimethylamino)-2-methylazobenzene 77. 4,6-Dinitro-o-cresol 78. 2,3-Dinitrophenol (--Dinitrophenol) 79. 2,4-Dinitrophenol (--Dinitrophenol) 80. 2,5-Dinitrophenol (--Dinitrophenol) 81. 2,6-Dinitrophenol (ß-Dinitrophenol) 82. 83. 3',3''-Dinitrophenolsulfonephthalein 84. 85. 2,4-Dinitrophenylhydrazine (DNPH) 86. 87. Direct Blue 72 88. Eosin Y 89. Erythrosin B 90. Esculetin 91. 92. Ethyl bis(2,4-dinitrophenyl)acetate 93. Ethyl Green 94. Ethyl Orange 95. Ethyl Orange, Potassium Salt 96. , Sodium Salt 97. Ethyl Red 98. Ethyl Violet 99. Fluorescein 100. Fluorescein diacetate (FDA) 101. (Uranine) 102. Fluoroscein-5-isothiocyanate (FITC) 103. Fluorexon 104. Gallein 105. Gentian Violet 106. Gentian Violet B 107. Guaiacolphthalein 108. Harmine 109. Hematoxylin 110. 111. Heptamethoxy Red 112. Hexamethoxy Red 113. Hexyl Orange 114. Hexyl Orange, Sodium Salt 115. 2-(2-Hydroxyphenyl)benzimidazole (2-(o-Hydroxyphenyl)benzimidazole) 116. 2-(2-Hydroxyphenyl)benzothiazole (2-(o-Hydroxyphenyl)benzothiazole) 117. 118. 119. Indophenol 120. Iodophenol Blue 121. Iodophenol Red 122. Isonitrosothiocamphor 123. Isopicramic acid 124. Lacmoid 125. Lanacyl Violet BF 126. Litmus 127. Luminol 128. LysoSensor Blue DND 167 129. LysoSensor Blue DND 192 130. LysoSensor Green DND 153 131. LysoSensor Green DND 189 132. LysoSensor Yellow/Blue DND 160 (PDMPO) 133. Magdala Red 134. Malachite Green 135. Martius Yellow (2,4-Dinitro-1-naphthol) 136. Mesalamine 137. Metanil Yellow 138. 2-Methoxybenzaldehyde 139. 4-Methylesculetin (6,7-Dihydroxy-4-methylcoumarin) 140. Methyl Green 141. Methyl Orange 142. Methyl Purple 143. Methyl Red 144. Methyl Red, Hydrochloride 145. Methyl Red, Sodium Salt 146. 4-Methylumbelliferone (7-Hydroxy-4-methylcoumarin) 147. 148. Methyl Yellow (Dimethyl Yellow) (Butter Yellow) (Fat Yellow) 149. 150. 2-Naphthol (ß-Naphthol) 151. Naphthol AS 152. 1-Naphtholbenzein (--Naphtholbenzein) 153. 154. 1-Naphtholsulfonephthalein (--Naphtholsulfonephthalein) 155. 1-Naphthylamine (--Naphthylamine) 156. 2-Naphthylamine (ß-Naphthylamine) 157. --Naphthyl Red (4-(Phenylazo)-1-naphthylamine) 158. Neutral Red 159. Nile Blue 160. Nile Blue A 161. Nitramine 162. Nitrazine Yellow 163. 4-Nitrobenzhydrazide (p-Nitrobenzhydrazide) 164. 4-Nitrobenzyl cyanide (p-Nitrobenzyl cyanide) 165. 4-Nitrocatechol (p-Nitrocatechol) 166. 2-Nitrophenol (o-Nitrophenol) 167. 168. 4-Nitrophenol (p-Nitrophenol) 169. 4-Nitrophenylacetylhydrazine (p-Nitrophenylacetylhydrazine) 170. 4-Nitrophenylhydrazine (p-Nitrophenylhydrazine) 171. Orange I 172. Orange II 173. Orange III 174. Orange IV 175. Oregon Green 488 carboxylic acid 176. Oregon Green 514 carboxylic acid 177. Oregon Green 488 carboxylic acid diacetate 178 Oxine Blue 179. Palatine Chrome Black 6BN (Calcon) 180. Patent Blue V 181. Pentamethoxy Red 182. Phenolbenzein 183. Phenolmalein 184. Phenol-1,2-naphthalein 185. Phenol-1,8-naphthalein 186. Phenol-2,1-naphthalein 187. Phenolphthalein 188. Phenolphthalein, Disodium Salt 189. Phenol Red 190. Phenol Red, Sodium Salt 191. Phenoltetrabromosulfonephthalein 192. Phenoltetrachlorosulfonephthalein 193. Phenoltetraiodosulfonephthalein 194. 4-(Phenylazo)diphenylamine 195. o-Phenylenediamine 196. p-Phenylenediamine 197. Phloxine B 198. Picric acid (2,4,6-Trinitrophenol) 199. Pinachrome 200. Poirrier Blue 201. Propyl Orange 202. 203. Propyl Orange, Sodium Salt 204. Propyl Red 205. Pyrocatechol Green 206. 207. Pyrogallolphthalein 208. Quinaldine Red 209. Quinine 210. Quininic acid 211. Quinoline Blue (Cyanine) (Cyanine Blue) 212. (Alamar Blue) 213 Resazurin Sodium Salt 214. Resorcein (Resorcein Blue) 215. Resorcinolmalein 216. Resorufin 217. p-Rosolic acid 218. Rubrophen 219. Salicyladehyde semicarbazone 220. Salicylic Acid 221. Salicyl Yellow 222. Sinalbin 223. Solochrome Violet RS 224. Sulphan Blue 225. Tetrabromophenol Blue 226. Tetrabromophenol Blue, Sodium Salt 227. Tetrabromophenolphthalein 228. 229. Tetraiodophenolsulfonephthalein 230. 3',3'',5',5''-Tetranitrophenolsulfonephthalein 231. Tetryl 232. Thiazol Yellow G 233. Thymolbenzein 234. Thymol Blue 235. Thymol Blue, Sodium Salt 236. Thymolphthalein 237. 1,3,5-Trinitrobenzene 238. 2,4,6-Trinitrobenzoic acid 239. 2,4,6-Trinitrophenylacetylhydrazine 240. 241. Tropaeolin O 242. Tropaeolin OO 243. Tropaeolin OOO 244. Umbelliferone (7-hydroxycoumarin) 245. p-Xylenol Blue 246. p-Xylenol Blue, Sodium Salt 247. Xylenol Orange 248. 249. Xylenol Orange, Tetrasodium Salt 250. m-Xylenolphthalein (2,6-Dixylenolphthalein) 251. p-Xylenolphthalein