A simple and rapid semi-automatic micro method for the determination of chloride in serum and urine

575

CLINICA CHIMICA ACTA

BRIEF

NOTES

A simple and rapid semi-automatic tion of chloride in serum and urine

micro method for the determina-

Recently we have described1 an automatic titration method of chloride with silver nitrate in acetic acid medium. The multipurpose apparatus is not expensive. The use of an ion-sensitive electrode enables the construction of a simple steering device (e.g., an adapted temperature controller having a proportionality band). Any motordriven burette is useful, but for our purposes the simple modified LKB-pump was used2. It was possible to determine chloride in serum and urine without the separation of the proteins or other substances from the sample. The samples are pipetted by means of a s-p1 San2 pipette. The results obtained with a solution of 0.01 M silver nitrate are given in Table I. The standard deviation (from about 5 analyses) was about 1%. The time required for a determination was about 2 min. A full load of the titration apparatus with the 70% acetic acid solution is sufficient for 30-40 determinations. Refilling the apparatus requires I-2 min. TABLE

I

.%+%p1e

Found

rnequivll using OUYmethod

Found nzequiv/l using coulometvic naethod

Serum

I 2

104.0 86.5

104 86

3 4 5 6

95.5 92.5 111.5 118.0 108.0

95 9o II0 118 106

7

Urine

I

2 3 4 5

8.0

8

25.5 27.0

25 27 I3 38

15.5 39.0

a

We thank Dr. J. B. J. Soons and Dr. H. A. M. Jacobs for the samples of serum and Drs. B. G. Blijenberg for the low-chloride urine samples. Analytical Laboratory, (The Netherlands)

Unioersity

W. KRIJGSMAN J. F. MANSVELD

of Utrecht,

B. GRIEPINK I W. KRIJGSMAN, J. F.MANSVELD AND B. GRIEPINK,~. Anal.Chenz., 2 J. SLANINA, P. C. M. FRINTROP AND B. GRIEPINK,~. Anal.Chem.,

249 (1970) 368. 246(196g) 28.

Received May 5th, rg7o Clin. Chim.

Acta,

zg (1970)

575