Photometric tests

All primary samples were analysed on site using photometric tests... 

Although all pancreatic enzymes are inactivated during intestinal transit, fecal outputs of several enzymes correlate with pancreatic enzyme secretion. Fecal chymotrypsin activity, which is comparatively stable in the lumen as well as in extracorporal fecal samples, can be measured by a commercially available photometric test kit. When performed on three consecutive days, this test detects severe pancreatic exocrine insufficiency, but sensitivity and specificity are low in mild-to-moderate cases. In addition, the test does not differentiate between porcine and human chymotrypsin, so that pan-creatin supplements need to be discontinued 5 days prior to the test. For this reason, however, the test is able to monitor a patient s compliance in severe pancreatic insufficiency appar-endy refractory to enzyme treatment. Patients... 

Stossel, T. P. (1973) Evaluation of opsonic and leukocyte function with a spectro-photometric test in patients with infection and with phagocytic disorders. Blood 42,121-130... 

Tsoukalas, V. and Grosch, W., Analysis of food deterioration-Comparison of some photometric tests. J. Am. Oil Chem. Soc., 54, 490, 1977. 

The sensor is based on a ferrocene-modified glucose oxidase electrode strip. For glucose determination, a drop of blood is transferred to a disposable enzyme electrode strip, which is then inserted into a pen-sized readout instrument. The response is more rapid than that of photometric test strips. Venous as well as capillary blood may be used as sample material. There are a number of systems that measure very rapidly and require less than 1-pl sample. 

Solutions were prepared from bidistilled water. BSA (fraction V, Boehringer-Mannheim) was used as a standard protein. Ninety-six-well, flat-bottomed polystyrene microtiter plates (Greiner, Cat. No. 655101) were used for the photometric tests. 

Leaching properties Shaking test (2), column test (10) and large-scale lysimeter test (4) were used to measure the leaching behaviour. The effluents were analysed using Zeeman AAS, ICP-MS, ion chromatography (Dionex Autoion 400) and photometric tests. Besides, pH values and electrical conductivity were measured. 

Referee Methods. The American Society for Testing Materials (ASTM) has collected a series of standard referee methods for the analysis of magnesium and its alloys (78). These methods are accurate over a larger range of concentration than the production methods, but are time consuming ia thek apphcation. The methods are based on potentiometric titration, photometric methods, or gravimetric methods. The photometric methods are most common and are relatively straightforward. 

So, extractive and photometric determination of 2,4-D with CV and also the test-scale for its semiquantitative determination with separation from instmmental basis are proposed. 

Brombenztiazo (BBT) is known to be one of the best reagents for extraction-photometric determination of cadmium(II). The reagent also fonus complexes with Co(II), Cu(II), Fe(II), Ni(II), Zn(II). The aim of this work was to develop a solid-phase reagent on the base of BBT immobilized on silica gel for sorption-spectroscopic and visual test determination of Cadmium, and also for soi ption-atomic-adsoi ption determination of total heavy metals contents in natural waters. 

The purpose of the nebuliser-burner system is to convert the test solution to gaseous atoms as indicated in Fig. 21.2, and the success of flame photometric methods is dependent upon the correct functioning of the nebuliser-burner system. It should, however, be noted that some flame photometers have a very simple burner system (see Section 21.13). 

Separation techniques may have to be applied if the given sample contains substances which act as interferences (Section 21.10), or, as explained above, if the concentration of the element to be determined in the test solution is too low to give satisfactory absorbance readings. As already indicated (Section 21.10), the separation methods most commonly used in conjunction with flame spectrophotometric methods are solvent extraction (see Chapter 6) and ion exchange (Chapter 7). When a solvent extraction method is used, it may happen that the element to be determined is extracted into an organic solvent, and as discussed above it may be possible to use this solution directly for the flame photometric measurement. 

As the DI plant becomes exhausted, silica leakage occurs in the treated MU water and the pH falls abruptly. Furthermore, where sodium ion leakage occurs from the cation bed, it produces a regenerative effect on the anion bed, which may also lead to silica leakage. To differentiate between the two phenomena, sodium ion leakage from the cation bed should be assessed directly using selective sodium-ion electrodes, flame photometric analysis, or other appropriate test methods. 

The visual detection limits for polyphenols and flavonoids are 0.2 to 1 pg substance per chromatogram zone [1]. The photometric detection limits are appreciably lower (see Procedure Tested ). 

Subcase b2 This case, called the paired f-test , is often done when two test procedures, such as methods A and B, are applied to the same samples, for instance when validating a proposed procedure with respect to the accepted one. In practicular, an official content uniformity" 5 assay might prescribe a photometric measurement (extract the active principle from a tablet... 

On the other hand, if only specific GC detectors, e.g. the electron capture, nitrogen-phosphorus or flame photometric detectors, are tested, the argument of lack of GC method sensitivity is not acceptable. In most cases mass spectrometric detectors provide the sensitivity and selectivity needed. Unfortunately, tandem mass spectrometry (MS/MS) or MS" detectors for GC are still not widely used in official laboratories, and therefore these techniques are not always accepted for enforcement methods. 

For multi-analyte and/or multi-matrix methods, it is not possible to validate a method for all combinations of analyte, concentration and type of sample matrix that may be encountered in subsequent use of the method. On the other hand, the standards EN1528 andEN 12393 consist of a range of old multi-residue methods. The working principles of these methods are accepted not only in Europe, but all over the world. Most often these methods are based on extractions with acetone, acetonitrile, ethyl acetate or n-hexane. Subsequent cleanup steps are based on solvent partition steps and size exclusion or adsorption chromatography on Florisil, silica gel or alumina. Each solvent and each cleanup step has been successfully applied to hundreds of pesticides and tested in countless method validation studies. The selectivity and sensitivity of GC combined with electron capture, nitrogen-phosphorus, flame photometric or mass spectrometric detectors for a large number of pesticides are acceptable. 

As a test of reproducibility of spot printing and staining, a 10 spot by 10 row array (100 spots total) were printed on three slides. All slides were stained in a single staining run, using the same secondary detection chemistry with DAB as a chromogen. While DAB cannot provide accurate photometric measurements, it can provide relative comparisons from one spot to another on the same slide. When the stained control slides were analyzed in this... 

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