A Revised Scheme for the Evaluation of Automatic Instruments for Use in Clinical Chemistry

Lewes, East Sussex, BN7 1LG). The reagent has been used manually to measure chloride ions in serum" and its use in continuous-flow automated methods has also been reportedv" where it was compared to an automated method using mercuric thiocyanate.A continuous-flow method is presented using this reagent which has been in routine use for several months. The results of analyses from this method were compared with those obtained from coulometric analyses, the latter being our routine technique for analysis of plasma chloride at the time. Experience with this reagent showed it to be extremely sensitive such that it could measure the small amounts of chloride in samples of sweat. The results of these low chloride analyses were compared with results obtained using an ion-specific chloride electrode. 1982; 19: 245-249 Automated and manual use of a sensitive reagent for the determination of chloride in biological fluids Biochemistry, Nevill Hall Hospital, Abergavenny, Gwent, NP7 7EG SUMMARY An automated method is described for the determination of chloride in biological fluids using a mercuric 2,4,6-tri-(2-pyridyl)-1,3,5-triazine reagent. Results obtained by this method compared favourably with those obtained by coulometric titration. The same reagent was used manually to measure the small amounts of chloride in sweat. The results obtained agreed well with the direct measurement of chloride using an ion-specific electrode. Ann Clin Biochem PETER E HOLDER From the Department of ClinicalThe displacement of thiocyanate from mercuric thiocyanate by chloride ion-has formed the basis of the automated continuous flow analysis of chloride in plasma for some years.P This paper presents the results obtained using an alternative reagent for the automated analysis of plasma chloride. This reagent proved to be very sensitive and was also used manually to estimate the low concentrations of chloride present in sweat samples.The basis of this alternative reagent is the formation of mercuric chloride when chloride ion is added to a solution containing a mercuric complex with 2,4,6-(2-pyridyl)-1,3,5-triazine in the presence of ferrous ion. When chloride ion combines with the mercuric ion to produce soluble undissociated mercuric chloride the 2,4,6-(2-pyridyl)-1,3,5-triazine released combines with the ferrous ion in solution to produce a blue-coloured complex.Interest in an alternative chloride reagent was stimulated by dissatisfaction with the automated mercuric thiocyanate method. To conform with calibration techniques already in use for the auto-Materials and methods mated analysis of other components of the routine electrolyte profile, a method was required which COULOMETRIC ANALYSIS would be linear, not only over the range of clinical Coulometric titrations for the analysis of plasma values normally encountered but also from zero chloride were performed on the Radiometer CMTIO chloride concentration up to that range. Attempts to chloride titrator (Radiometer, Copenhagen, Denset up an automated chloride analysis using mercuric mar...

Section: Number Of Mean Value Standard Results (Mmoljl) Deviationmentioning

confidence: 99%

Automated and Manual Use of a Sensitive Reagent for the Determination of Chloride in Biological Fluids

Holder

1982

“…Filter papers 9 is prone to imprecision from both over-and under-saturation of the paper, and the step of punching out the paper disc may itself account for a CV of 3 %. 3 10 With the 5 ILl capillary, we obtained a CV of 1· 3 % by filling preweighed capillaries (n = 50) with whole blood and reweighing after wiping off excess blood. The CV was higher 0·7 %) when capiIlaries (n = 50)…”

Section: Discussionmentioning

confidence: 99%

A Novel Five-Microlitre Capillary System for Home Glucose Monitoring

Williams

Davies²,

Child

1981

Improvement in the control of diabetic patients is aided by a knowledge of blood glucose levels during a ‘normal’ (non-hospitalised) day. We have devised a 5 μl capillary tube collection system as a ‘kit’ for home use by diabetics. Blood collected into 5 μl capillary tubes is washed into a protein precipitant by the patient. The completed kit is posted to the laboratory for analysis. The technique has achieved a high degree of patient acceptability. Subsequent analysis involves the addition of a single reagent. Reagents, patient samples, and standards are stable, and the precision of the technique compares favourably with our routine glucose procedure.

“…In the author's laboratory the sampling .offfuoride-c-oxalated specimens is most speedily and analysis of whole blood or plasma which has previously been diluted I in 20 and are linear up to the value of the highest standard with sampling rates of 6O/h (AAI) and 9O/h (AA2). Carryover, as determined by the procedure described by Broughton et al (1974) was 1.6% and 1.3 % on two separate occasions on the AAI and 1.2%for the AA2 method estimated on one occasion only. Within-batch precision was estimated for each method by analysing sequentially three aqueous glucose solutions and three diluted whole-blood samples in random order until 20 results of each were obtained.…”

Section: Sample Preparationmentioning

confidence: 92%

A Modification of the Trinder AutoAnalyzer Method for Glucose

Richardson

1977

This paper describes the application of the sulphonated 2,4-dichlorophenol/glucose oxidase method of Barham and Trinder for the estimation of blood glucose to the AutoAnalyzer I and AutoAnalyzer II. Use has been made of the increased sensitivity achieved with this reagent to (1) increase sampling rates, with concomitant reduction in sample volume, (2) reduce the consumption of enzymes required, and (3) reduce carryover, all without significant loss of precision.