Economy pH Electrodes The ASI Economy line of pH electrodes pro- vide reliable,accurate performance.Popular in routine pH determinations,these models come in several designs.Featuring removable bulb quards and replaceable reference junc- tion elements,the ASI economy line offers high performance at attractive prices.Most models are shipped with a soaker bottle which guarantees high performance out of the box without conditioning. ASI P/N Range Size Temp range HO31 General purpose.combo 0-14PH Plastic body.gel tiled,removable guard 12 mm x 150 mm 080C HORJ General purpose.combo 0-14H Plastic body.gel filed,replaceable junction 12 mm x 150 mm 0g0℃ H035 General purpose.combo 0-14 Epoxy bodye illed tedur 12 mm x 150 mm 0-800 HO35NAOOD General purpose.combo 0-14H Epoxy body,gel filled fxed guard,double unction 12mmX150m0 0-80℃ HO11 General purpose,comba 0-14H Ghss body.gel filled 12 mm x 150 mm 0-100c H014 General purpose.comb 0-14 pH Glass body,refilable 12 mm x 150 mm 0-1000
Differences Between pH and Other lon-Selective Electrodes In contrast to the pH membrane,other ion-selective membranes are not entirely ion-specific and can permit the passage of some of the other ions which may be present in the test solution,thus causing the problem of ionic interference
Differences Between pH and Other Ion-Selective Electrodes ◼ In contrast to the pH membrane, other ion-selective membranes are not entirely ion-specific and can permit the passage of some of the other ions which may be present in the test solution, thus causing the problem of ionic interference
Solid state electrodes A very popular type of ion specific eledtrode. As easy to maintain as a pH electrode. F electrode The original solid state Works by creating defects in a LaF,aystal. Other solid state electrodes work based on the presence of a primary absorbed ion
1.晶体电极11-利 敏感膜由难溶盐的单晶或多晶沉淀压片制成。单晶电极现在 只有用LaF3制成的，它是离子选择电极中最好的一种，其他单 晶如CuS,CuSe,AgCl等不是造价太高，就是性能不好，反不如 多晶电极为好.多晶电极中一类是卤化银加AgS压片，用以测 Ag+,I,Br,CI,CN,SCN等离子.另一类是重金属硫化 物加AgS压片，用于测重金属离子及S2-等离子，与Ag+或S2- 有沉淀或络合反应的离子都千扰测定。均相膜是多晶直接压片， 异相膜是多晶中掺以惰性物质热压而成。后者制膜时不需用高压 且膜的机械性能较好，但响应较慢，内阻较高，不适用于有机介 质
晶体膜的响应机理 晶体膜的响应机理一般用晶体中离子传导原理及膜表面上相同离子间的扩散作用来解释 已知只有很少几种晶格能较低的晶体在室温下具有离子导电性.在晶体中，一般仅有一种晶格 离子参加导电过程.这通常是离子半径最小和电荷最少的晶格离子，如LF3中的F-,AgS 和AgX中的Ag*等 离子在晶体中的导电过程，是藉助于晶格缺陷而进行的.挨近缺陷空穴的导电离子，能移 动至空穴中，其移动过程可表示如下： LaF;+空穴→LaF+F 离子的移动便传导电流， 由于缺陷空穴的大小、形状和电荷分布，只能容纳特定的可移动的晶格离子，其它离子不 能进入空穴，故亦不能参与导电过程.因此，在晶体敏感膜中，只有待测离子能进入膜相，并 参与导电过程，从而使晶体敏感膜具有选择性」