Nephelometric analysis

In actual practice, the so called visual nephelometer (comparator type) have been more or less superseded by the photoelectric instruments Nevertheless, a Duboscq Colorimeter with a slight modification may be used conveniently for nephelometric analysis, for instance ... 

Measurement of the intensity of the transmitted light as a function of the concentration of the dispersed phase is the basis of turbidimetric analysis and measurement of the intensity of the scattered light (at right angles to the direction of incident light) as a function of the concentration of dispersed phase constitute the basis of nephelometric analysis. 

Flow Nephelometric Analysis of Protein-Tannin Interactions 385... 

Fig. 9D.12 Flow nephelometric analysis of the inhibitory effect of gum arabic on aggregate formation between procyanidins (tetramers-digaUate and pentamers-gaUate, 0.034 g/L) and BSA (0.33 g/L) (adapted from Carvalho et al. 2006a)...

Gauldie J, Bienenstock J. Automated nephelometric analysis of haptens. In R Ritchie R, ed. Automated Immunoanalysis Vol. 7, Part 1. New York Marcel Dekker, Inc, 1978 321-33. 

Seligson s group (95) has published a similar turbidimetric procedure but used nephelometry to measure continuously the effect of lipase on the light scattering of an olive oil emulsion. The instrumentation and approach is the same as that described above for the nephelometric determination of amylase. The method according to the authors is fast and precise with good specificity and sensitivity. The short time required for analysis makes it suitable for emergency use. The technical simplicity permits this method to be easily automated, and it appears to be the lipase method of choice. 

Table 9.12 Nephelometric and conductometric analysis of zinc ions in alkaline medium...

UV spectra of these solutions were recorded and the concentration of zinc was measured from the absorbance value and the results obtained have been shown in Table 9.11. In another experiment, the nephelometric and conductometric analysis were carried out but only after diluting the solutions from 5 to 1 M of NaOH, since the conductivity of solutions above this concentration was beyond the scale of the conductivity meter. 

Note that turbidity measurement plays an important role in many types of routine chemical analyses (e.g. nephelometric determination of water quality, the evaluation of the concentration of barium and sulphate, or potassium determination with sodium tetraphenylbo-rate in water analysis, and determination of seric proteins). Also, the characterization of turbidity measurements is very important when evaluating some sources of uncertainty in gravimetry used in valid chemical metrology [5],... 

Stowe H, Lawrence D, Newman D, Lamb EJ. Analytical performance of a particle-enhanced nephelometric immunoassay (PENIA) for serum cystatin C using rate analysis. Clin Chem 2001 47 1482-5. 

Snell, F. D. Snell, C. T, "Colorimetric Methods of Analysis Including Some Turbidimetric and Nephelometric Methods," 3rd ed. Van Nostrand Princeton, N.J., 1971 Vol. 4AAA. 

A nephelometric method was developed for the analysis of levallorphan tartrate in the presence of levorphanol tartrate. The method takes advantage of the kinetics of bromination of the allyl function on levallorphan which in acidic aqueous medium is faster than the bromination of the levorphanol. The bromination product is insoluble and hence lends itself to a turbidimetric determination (21). The procedure involves adding 1 mg of levallorphan tartrate (along with up to 10 mg of levorphanol tartrate) to 5 ml of 2.5N HCl and 15 ml of water in a glass stoppered 25-ml graduated cylinder. Bring to 25°C and add... 

ABEI produces ECL when oxidized at 1.0 V versus Ag/AgCl in alkaline aqueous solution. In contrast to luminol, ABEI labels do not markedly lose their CL efficiency when conjugated with proteins. ECL immunoassays with a flow injection analysis (FIA) system using ABEl-isothiocyanate as a label were proposed, which have a better performance than either single-radial immunodiffusion or nephelometric immunoassays. ABEI can also be used as an oligonucleotide marker to label a DNA probe. The intensity of the ABEI ECL was linearly related to the concentration of the complementary sequence in the range 96-96 nM, and the detection limit was down to 30 pM. 

Morais IP A, Toth IV, Rangel AOSS. Turbidimetric and nephelometric flow analysis concepts and applications. Spectrosc Lett 2006 39 547-79. 

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