Periodic acid, detection acids

A modification of the periodic acid/thiobarbituric acid method has been described by excitation of the usual chromophore at 550 nm and measurement of the emission at 570 nm (Hammond and Papermaster 1976). The assay is 500-fold more sensitive than the conventional spectrophotometric procedures and can detect lOng sialic acid. Deoxyribose remains a problem with this assay and the precautions detailed for the periodic acid/thiobarbituric acid assay are required if accurate quantitation is to be made (Hammond and Papermaster 1976). 

The polyhydric alcohols of Solubility Group II are liquids of relatively high boiling point and may be detected inter alia by the reactions already described for Alcohols (see 6). Compounds containing two hydroxyl groups attached to adjacent carbon atoms (1 2-glyeols), a-hydroxy aldehydes and ketones, and 1 2-diketones may be identified by the periodic acid test, given in reaction 9. 

Periodic acid-Schiff reagent Detects glycoproteins as pink bands after electrophoretic separation. 

Figure 52-3. Diagrammatic representation of the major proteins of the membrane of the human red blood cell separated by SDS-PAGE. The bands detected by staining with Coomassie blue are shown in the two left-hand channels, and the glycoproteins detected by staining with periodic acid-Schiff (PAS) reagent are shown in the right-hand channel. (Reproduced, with permission, from Beck WS, Tepper Ri Hemolytic anemias iii membrane disorders, in Hematology, 5th ed. Beck WS [editor]. The MiT Press, 1991.)...

The band number refers to the position of migration on SDS-PAGE (see Figure 52-3). The glycophorins are detected by staining with the periodic acid-Schiff reagent. A number of other components (eg, 42 and 4.9) are not listed. Native spectrin is... 

Sakamoto [243] determined picomolar levels of cobalt in seawater by flow injection analysis with chemiluminescence detection. In this method flow injection analysis was used to automate the determination of cobalt in seawater by the cobalt-enhanced chemiluminescence oxidation of gallic acid in alkaline hydrogen peroxide. A preconcentration/separation step in the flow injection analysis manifold with an in-line column of immobilised 8-hydroxyquinoline was included to separate the cobalt from alkaline-earth ions. One sample analysis takes 8 min, including the 4-min sample load period. The detection limit is approximately 8 pM. The average standard deviation of replicate analyses at sea of 80 samples was 5%. The method was tested and inter calibrated on samples collected off the California coast. 

System (6) has been described for the simultaneous determination of submicrogram amounts of 17a-deoxy and 17a-hydroxy corticosteroids [145]. Prior to analysis, the corticosteroids were treated with periodic acid in 50% aqueous dioxane, and extracted with dichloromethane. Acylation of the 3- and 17a-hydroxyl groups was carried out using 1 1 butyric anhydride and pyridine. 4- C -cholesterol was added as the tracer, and cholesterol isobutyrate as the internal standard. The column used was glass (8 ft X 5 mm) packed with 1% SE 30 or QF-1 on GasChrom Q (100-120 mesh), and was operated at 250-260°C. Argon (at a flow rate of 30 mL/min) was used as the carrier gas, and detection was by a Sr detector. It was reported that the corticoids could be determined with a precision of approximately 15% down to levels as low as 0.1-0.2 pg. 

A further method for estimation of sialic acid using periodic acid has been reported by Massamiri and coworkers.121 Fonnaldehyde produced by mild, oxidative cleavage of the D-en/f/iro-glycerol-l-yl side-chain of Neu can be detected by 3-methyl-2-benzothiazolinone hydrazone, which yields a green-blue color (absorbance maximum 625 nm). This test, which is slightly more sensitive than the thiobarbi-... 

The test for ethylene glycol was performed by oxidation of the sample with periodic acid and detection of the resulting formaldehyde with fuchsin-sulfurous acid reagent (9). 

Carbohydrates were cy to chemically detected in hydrogenosome membranes using the periodic acid-thiosemicarbazide-silver proteinate technique (Fig. 6a) and gold-labeled lectins, such as WGA (Fig. 6b) (Benchimol... 

The second of the three types of qualitative teste mentioned above involves acid-catalyzcd cleavage of an epoxide with periodic acid.38 The IOf ion then oxidizes the resulting 1,2-diol in the usual manner, while itself undergoing reduction to iodato. In the presence of AgH ion, the gradual formation of iodate will be marked by precipitation of silver iodate (Eq. 983). An obvious drawback to this procedure is that any other functional groups capable of reducing IOf iou will interfere with epoxide detection. 

A more general method for carbohydrates that can be used equally well on handsections and on sections of plastic embedded materials uses the Periodic acid SchifFs (PAS) reaction or one of its variants [29] for vicinal hydroxyl groups [22,23]. Sections are treated with 1%W/V Periodic acid at room temperature for 10 minutes and rinsed. The aldehydes created by this treatment are detected with SchifFs reagent (decolorized para-rosaniline) by immersion for 30 minutes. A red color (or fluorescence with excitation at 540 nm) indicates vicinal hydroxyl groups in starch and many other carbohydrates. If the specimen has been fixed with aldehydes then an aldehyde-blocking step must precede this reaction [22]. The best treatment is immersion for 24 hr in a saturated solution of dimedone. 

In order to test the adsorption behaviors of this kind of macroporous materials, three colored materials Rhodamine B, indophenol, and methyl violet were chosen. The changes of concentrations of the solutions of dyes in a period were detected by UV-VIS spectrometer. The adsorption isotherms are shown in Figure 6. From the adsorption isotherms we can see that the adsorption behaviors of macroporous materials are not good. The reason may be (I) that the surface areas of macroporous materials are low ca. lOOmVg) and the active sites are few (II) the solvent ethanol was adsorbed by the hybrid materials. The adsorption isotherms of three colored materials were different. Methyl violet was an alkaline indicator and the adsorption of methyl violet and hybrid materials may correspond to a chemisorption. Acid indicator Rhodamine B was not adsorbed by the adsorbent and the solvent ethanol was adsorbed instead. Therefore, after reaction the concentration of the solution increased and the adsorption capacity appeared negative. Compared with the former two, indophenol molecule is smaller and is easy to be absorbed. Therefore, its adsorption behavior is stronger relatively. 

Histochemical techniques for detecting substrate before and after enzyme treatment are extremely useful in studies on cellular structure. One of the oldest histochemical tests utilized saliva to identify suspected glycogen or starch. More definitive results are obtained when thin sections of a tissue are incubated in a buffered solution of purified amylase and stained for poly-utc-glycols. Material stained by periodic acid-Schiff reagent in the control, but not in the section exposed to amylase, is assumed to be glycogen or starch. Two more of the numerous histochemical techniques associated with localization of substrate are—using hya-luronidase to locate hyaluronic acid and chondroitin 4- and 6-sulfates (179) and using neuraminidases to locate sialomucins (180). By use of electron microscopy in combination with the histochemical technique subcellular localization can be obtained. 

Alternatively, over very long time periods, L-amino acids can racemize to produce D-amino acids. However, measured d/l ratios for certain amino acids cannot be achieved based on known racemization rates of amino acids in seawater. For example, Lee and Bada (1977) calculated d/l ratios of 0.01 and 0.004 for aspartic acid and alanine, respectively, assuming an oceanic residence time of 3,400 years for these amino acids. These calculated values are much lower than the measured values and led Lee and Bada (1977) to conclude that the enhanced D-amino acid concentrations in marine DOM must be derived from a bacterial source. In a later paper, Bada et al. (1982) suggested that the near-racemic mixture (50% each of the d and l enantiomer) of alanine at depth in the ocean was a result of the dehydration of serine or threonine to produce racemic alanine. These authors also detected near racemic a-amino- -butyric acid (ABA), which can be produced from the dehydration of threonine. This mechanism of D-alanine formation... 

The formation of diol-periodate esters is supported by physical evidence. The addition of ethane-1,2-diol to periodate solutions causes an initial rapid change in the uv absorption spectrum, followed by a slower change as the oxidation proceeds and lOJ is formed. Similar results are observed for other 1,2-diols except for highly substituted diols such as pinacol (Buist et al ). Buist and Bunton have shown that the cyclic periodate esters formed in alkaline solution from 1,2-diols and periodate can be detected by nmr. The initial fall in pH which occurs in the oxidations of ethane-1,2-diol and lightly substituted diols is also attributed to ester formation (Malaprade, Buist and Bunton ). Cyclic triesters, similar to the cyclic diesters formed from 1,2-diols, are formed from cyclic compounds containing the cis-l,2,3-triol system (Barker and Shaw , Dijkstra and from 1,2-0-isopropylidene-a-D-glucofuranose. In the latter case the presence of the triester has been demonstrated by nmr (Berlin and van Rudloff ). Monoesters of periodic acid have not been detected in any system, but they are postulated as intermediates in the formation of cyclic diesters from 1,2-diols (section 1.3.5). 

Six moles of periodic acid were consumed per mole of streptamine with no formation of formaldehyde. - - Under comparable conditions, meso-inositol (m. p. 225°) was stated to consume six moles of periodic acid (formic acid was not detected or measured) and to give no formaldehyde while D-mannitol under like conditions consumed five moles of oxidant with the formation of two moles of formaldehyde. It is noteworthy that the periodic acid oxidation of the unsubstituted natural meso-inositol (see page 46) had been shown by Fleury, Poirot and Fievet to be anomalous (see page 51). 

Periodic Acid Test for vic-Glycols. Vicinal glycols (hydroxyl groups on adjacent carbon atoms) can be detected by reaction with periodic acid. In addition to 1,2-glycols, a positive test is given by a-hydroxy aldehydes, a-hydroxy ketones, a-hydroxy acids, and a-amino alcohols, as well as 1,2-diketones. 

Vitamin K status can be assessed by a functional test, called the "prothrombin time test," which involves measuring the lime required to form a blood clot. The test is performed as follows. A blood sample is withdrawn from a subject and immediately mixed with citric acid. Citric acid is a chelator, which means that it can form a tight complex with ions, such as calcium ions. The chelator prevents the interaction of calcium ions with the blood-clotting proteins and thus prevents these proteins from forming a blood clot in the sample. Calcium ions, it should be noted, are required for supporting the activity of several blood clotting proteins. The "citrated blood" is placed in a machine called a fibrometer. The fibrometer is used to detect increases in the viscosity of the blood over a period. 

The sedoheptulosan structure remains unique. Haskins, Hann and Hudson " have attempted to confirm formula XXI for that compound by oxidizing it with periodic acid and with sodium metaperiodate. Two equivalents of oxidant were consumed, one equivalent of formic acid was produced, and no formaldehyde could be detected in the oxidation mix-... 

In addition to staining for total protein, electrophoretic gels can be used for detection of specific protein components. This can be done, for example, by treating the gel in conditions suitable to reveal enzymatic activities, such as chitinolytic (Vincenzi and Curioni, 2005), or staining for glycoproteins with the periodic acid-Schiff method (PAS) (e.g. Marchal et ah, 1996). 

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