The potentiometric titratrion of aluminum and gallium with tetraphenylborate
The potentiometric titratrion of aluminum and gallium with tetraphenylborate*
Walter S. Selig 0 1
0 Division of Gastroenterology and Hepatology, Medizinische Hochschule Hannover , Podbielskistrasse 380, D-3000 Hannover 51, Federal Republic of Germany
1 Lawrence Livermore National Laboratory, University o f California , P. O. Box 808, Livermore, CA 94550 , USA
Various cations have previously been determined as their oxonium complexes by potentiometric titration vs. tetraphenylborate (TPB). This includes the alkaline earth metals , the rare earth elements , and lead [2, 3]. Some of these elements can, in fact, be sequentially estimated [1, 2]. With the exception of lead, these elements are in group IIA or IIIB of the periodic table of the elements. We now report that aluminum and gallium, in group I I I A of the periodic table, can similarly be determined. The oxonium complexes were formed by addition of polyethylene glycol (PEG) of average molecular weight 20,000, and were potentiometrically titrated with a 0.05 tool/1 TPB solution.
* Work performed under the auspices of the U. S. Department
of Energy by the Lawrence Livermore National Laboratory
under contract number W-7405-ENG-48
Ion-exchange high-performance liquid
chromatographic determination of leukotrienes after prel
column derivatisation with o-phthal~aldehyde
Ionen-Austauscher-HPLC-Bestimmung yon Leukntrienen
nach Vors~iulen-Derivatisierung mit o-Phthaldialdehyd
Cysteinyl leukotrienes LTC4, LTD4 and LTE4 are endogenous
mediators in anaphylactie and inflammatory reactions [I, 2].
The increasing interest in the biochemistry of the leukotrienes
has necessitated the development of sensitive methods for the
determination of these metabolites. Reversed-phase
high-performance liquid chromatography (HPLC) with detection by
UV, radioactivity and fluorescence are the most widely used
chromatographic methods for the determination of leukotrienes
3 - 7
]. We have developed a HPLC method for the
determination of LTC~, LTD4, and LTE4 using an ion-exchange column
and pre-column derivatization with o-phthaldialdehyde.
Reagents and materials. Cysteinyl leukotrienes LTC4, LTD4, and
LTE~ were purchased from Paesel (Frankfurt, FRG) and used
as received, o-Phthaldialdehyde (OPA) and ammonium acetate
were obtained from Fluka (Neu-Ulm, FRG).
2-Mercaptoethanol was purchased from Schuchardt (Mfinchen, FRG).
Methanol for HPLC and all other chemicals were from Merck
(Darmstadt, FRG). All reagents were of the highest quality available
and were stored as recommended. The column (200 mm
x 4.6 mm LD.) packed with an ion-exchange material,
1005NH2 Nucleosil, was obtained from Macherey-Nagel (Diiren,
1. Selig WS ( 1986 ) Fresenius Z Anal Chem 325 : 616
2. Selig WS ( 1988 ) Microchem J 37:155
3. Xiang Y , Yang B , Liu M ( 1985 ) Huaxue Xuebao 43 :1203; through ( 1986 ) Chem Abstr 104:179259g
4. Setig WS ( 1986 ) Microchem J 34:148