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Biomedical subjects

B F Rocks

Publications and source records attributed to B F Rocks.

32 records · Page 2Linked to original sources
PubMed1984

Direct determination of calcium and magnesium in serum using flow-injection analysis and atomic absorption spectroscopy.

The use of flow-injection analysis for the direct determination of calcium and magnesium in blood serum and plasma is described. An inexpensive rotary valve is used to inject the serum sample (4 microliters) into a flowing non-segmented stream of reagent which carries the sample slug through a long narrow-bore coil--where it gradually disperses--and into the nebuliser of an atomic absorption spectrometer. This on-stream sample dilution removes the need for predilution of the sample. The resulting absorbance signals are recorded as peaks less than 40 seconds after sample injection. Analytical recoveries and precision are good for both elements and the results by flow-injection analysis compare well with established routine methods.

Calcium↗
PubMed1984

Homogeneous fluoroimmunoassay using Lucifer yellow VS: determination of albumin plasma.

Non-separation fluoroimmunoassays are well suited to automation. The potential sensitivity of such assays has not been realised because the most commonly used label (fluorescein) has absorption and emission spectra which coincide with those of blood constituents and because it has a very small Stokes shift. Lucifer yellow VS has a larger Stokes shift than fluorescein and an emission maximum at longer wavelength. We describe an energy transfer fluoroimmunoassay for plasma albumin in which Lucifer yellow VS is used to label albumin and rhodamine B isothiocyanate is used to label anti-albumin antibodies. The assay shows good correlation with a dye-binding method for albumin and has sensitivity and precision which compare favourably with similar assays using a fluorescein label.

Energy Transfer↗
PubMed1983

Serum iron and total iron-binding capacity determination by flow-injection analysis with atomic absorption detection.

The deproteinised sample (150 microliters) is 'injected' into a continuously flowing stream of deionised water which is pumped, via a capillary tube, to the nebuliser of an atomic absorption spectrophotometer. Analytical readout is obtained, in the form of transient peaks, 6 s after sample injection. Before injection traces of haemoglobin are removed from the serum by treatment with trichloroacetic acid-ascorbate solution. This protein precipitant facilitates rapid removal of haemoglobin bound iron without the need for heating. After centrifugation the supernatant solution is introduced into the flowing stream by use of a novel inexpensive 'injector'. Analytical recovery and precision are good, and results compare well with those obtained by a standard AutoAnalyzer procedure.

Autoanalysis↗
PubMed1983

Use of Lucifer yellow VS as a label in fluorescent immunoassays illustrated by the determination of albumin in serum.

The use of a new label for fluoroimmunoassay is described. Lucifer yellow VS is a highly fluorescent vinyl sulphone dye which, under mild conditions, forms covalent bonds with amino and sulphydryl groups but is extremely stable in water. A large Stokes shift (110 nm) and an emission maximum at 540 nm give Lucifer yellow further advantages over the more commonly used labels. The use of the dye as a label has been demonstrated by developing a heterogeneous fluoroimmunoassay for human serum albumin. The fluoroimmunoassay gave comparable results to those obtained using a less specific colorimetric dye-binding assay (r = 0.97, n = 20). The advantages, limitations, and other potential uses of Lucifer yellow are discussed.

Colorimetry↗
PubMed1983

Controlled dispersion analysis: flow-injection analysis without injection.

Flow-injection analysis is a precise, elegant, and economical technique, but its most troublesome feature is the mode of injection of the sample slug. We describe an alternative approach in which the sample is aspirated by the sample probe. In the simplest version the probe normally rests in reagent; when sampling is to take place, the pump is stopped and the probe is transferred to the sample container. The pump makes a predetermined angular movement, the probe is returned to reagent, and the pump is restarted. In more advanced versions the same approach is combined with the merging zone technique. The system is economical, precise, and capable of full automation in a multichannel discretionary analyzer.

Autoanalysis↗
PubMed1982

Antenatal diagnosis of steroid sulphatase deficiency: case report and literature survey.

Steroid sulphatase deficiency is a recently recognised genetically determined inborn error of metabolism. Originally identified as an enzyme disorder of the placenta (commonly termed placental sulphatase deficiency), it is now known that the progeny of affected pregnancies have a generalised steroid sulphatase deficiency and that the enzyme defect persists throughout life. The disorder is characterised clinically by markedly low maternal oestrogen excretion in the presence of normal fetal growth and development. The importance of antenatal diagnosis lies in the differentiation of this disorder from the more ominous fetal defects that result in low oestrogen concentrations. This paper summarises the relevant literature and describes a case in which biochemical tests were used for the antenatal diagnosis of steroid sulphatase deficiency. The pregnancy resulted in a healthy baby boy delivered vaginally after a spontaneous labour.

Adult↗
PubMed1982

Zinc and copper determination in microsamples of serum by flow injection and atomic absorption spectroscopy.

A new approach to the direct determination of copper and zinc in serum and plasma is described. The sample is injected into a continuously pumped stream of water which is fed into the nebuliser of an atomic absorption spectrophotometer. Analytical results are obtained as a series of sharp peaks on a chart recorder. Analytical variables have been investigated, and the proposed method gave results comparable to those obtained using a conventional method based on precipitation of serum proteins with trichloroacetic acid. The proposed method takes less time to perform and was found to give more precise results than the conventional method. In addition, the flow injection analysis method can be performed using microsamples (10-100 microliters) and is thus ideally suited for use on children.

Copper↗
PubMed1982

Direct determination of therapeutic concentrations of lithium in serum by flow-injection analysis with atomic absorption spectroscopic detection.

In this flow-injection system for direct determination of lithium in serum by atomic absorption spectroscopy, the 10-microL sample is manually injected into a continuously flowing non-segmented stream of de-ionized water, which is pumped, via a dispersion tube, to the spectrometer's nebulizer. Controlled dispersion of the sample zone, before it is introduced into the nebulizer, produces the required sample dilution. Effects of varying the length of the dispersion tube, the flow rate, and the sample size were studied. Analytical readout is obtained, in the form of transient peaks, 5 s after sample injection. It is necessary to include physiological concentrations of sodium and potassium in the standard because each of these cations enhances the lithium absorbance signal. Analytical recovery (98.5 to 101%) and CV (about 2%) are good, and results compare well with those obtained by aspiration of prediluted samples (n = 121, r = 0.99).

Chemistry, Clinical↗