Marker substance

Substances or preparations requiring to be labelled with the risk phrase R45 (may cause cancer) or R49 (may cause cancer by inhalation) under CHIPS are listed in Table 5.16 after the 5th edition of the Approved Supply List (Information approved for the classification and labelling of substances and preparations dangerous for supply). This list excludes certain coal and oil-based substances which attract the phrase R45 only when they contain a certain percentage of a marker substance (e.g. benzene). 

The Use of PLC for Isolation and Identification of Unknown Compounds from the Frankincense Resin (Olibanum) Strategies for Finding Marker Substances... 

As there exists such a distinct difference in the spectrum of the volatile diterpenic components of both species, it would be advantageous to transfer these results to TLC in order to display these taxonomic marker substances as a tool for quality assurance operations. 

FIGURE 16.3 Decisive diterpeiies as marker substances of B. carterii and B. serrata resins. 

The solutions of the olibanum resins reveal an unpleasant property of stickiness. This must be considered with all steps of analyzing and isolation. That is why a preceding column chromatography (CC) is recommended, to enrich the diterpenes of interest. The further purifieation of the supposed marker substances was carried out by PLC. 

The separation and collection of the violet zone (Rj 0.98) of fraction 1 led to the isolation of m- and p-camphorene (compound 4 and compound 5) and cembrane A as well. Thongh m- and p-camphorene are taxonomic marker substances of the species B. serrata, it is pointless to use them in TLC, because the corresponding violet spot on the chromatogram of B. carterii stands for verticilla-4(20),7,l 1-triene, the taxonomic marker substance of B. carterii and cembrene A, too. These violet snbstances shonld be reserved for GC investigations. 

To summarize, generally, the diterpenes of both investigated Boswellia species are suitable for marker substances. Figure 16.9 clearly demonstrates that for TLC... 

FIGURE 16.9 An overview of the marker substances of (A) B. carterii and (B) B. serrata. (A) Lane 1 incensole (compound 3), lane 2 and 3 hexane extract of B. carterii, lane 4 incensole acetate (compound 2), lane 5 verticilla-4(20),7,ll-triene (compound 1). (B) Lane 1 m-camphorene (compound 4) and p-camphorene (compound 5), lane 2 cembrenol (compound 6), lane 3 Hexane extract of B. serrata. 

This observation is used to calculate cardiac output by using a suitable marker substance such as oxygen, heat or dye and the following equation ... 

A marker substance is injected into a central vein. A peripheral arterial line is used to measure the amount of the substance in the arterial system. A graph of concentration versus time is produced and patented algorithms based on the Stewart-Hamilton equation (below) are used to calculate the cardiac output. 

Furthermore, our own studies showed that not all inhibitors seem to be useful for their suggested application in all cell types. Some inhibitors (amiloride and indomethacin) did not show an effect (not even on the uptake of the corresponding marker substances) in COS-7 and HUVEC. Consequently, not only one but a series of inhibiting agents with preferably different modes of inhibition should be applied and combined with colocalization studies. 

The marker substance for Bacillus endospores is calcium dipicolinate (CaDPA). One approach is the isolation of CaDPA from a minimal amount of spores and its subsequent identification by SERS spectroscopy [97]. The detection of CaDPA in endospores was used for the detection of minimal amount of spores [98] even in automated mail sorting systems [99]. The detection of CaDPA does not give any information about the Bacillus species present. The investigation of the components in the outmost layers of the endospores, the outer sporecoat, or the exosporium will lead to more precise information,... 

Grammer, J.B., et al. 1996. Impregnation of collagen corneal shields with liposomes Uptake and release of hydrophilic and lipophilic marker substances. Curr Eye Res 15 815. 

Another sign of therapeutic response is a significant decrease in the quantity of a tumor product or marker substance that reflects the amount of tumor in the body. 

The third category of drugs are phytotherapeutical preparations 80% of the world population use exclusively plants for the treatment of illnesses [11]. Chromatography is relied on to guarantee preparations contain therapeutically effective doses of active drug and maintain constant batch composition. A quantitative determination of active principles is performed when possible, using pure reference standards. In many phytotherapeutic preparations, the active constituents are not known, so marker substances or typical constituents of the extract are used for the quantitative determination [11]. The Applications chapter of this book (Chapter 8) contains numerous references to the use of chromatographic methods in the control of plant extracts. 

Figure 26-4. Principle of the Pancreolauryl and the NBT-PABA (V-benzoyl-i.-tyrosyl-P-aminobenzoic acid, bentiromide) test. The composite molecule consisting of a substrate and a marker molecule cannot be absorbed but can be cleaved intraduodenally by pancreatic enzymes (cholesterol esterase and chymotrypsin, respectively), leading to release of an absorbable marker substance. Following absorption and hepatic conjugation, the marker is excreted in urine. In pancreatic-insufficient patients, decreased secretion of pancreatic enzymes results in incomplete cleavage of the composite molecule. This results in decreased absorption and subsequent excretion of the marker, which can be measured photometrically.

Marker substances and content tests—establish standards for quantitative chemical analysis of botanical for the presence of certain marker substances that aid in proper identification. 

In a capillary tube, the applied electric field E is expressed by the ratio VILj, where V is the potential difference in volts across the capillary tube of length Lj (in meters). The velocity of the electro-osmotic flow, Veo (in meters per second), can be evaluated from the migration time t of (in seconds) of an electrically neutral marker substance and the distance L, (in meters) from the end of the capillary where the samples are introduced to the detection windows (effective length of the capillary). This indicates that, experimentally, the electro-osmotic mobility can be easily calculated using the Helmholtz-von Smoluchowski equation in the following form ... 

The electrically neutral marker substance employed to measure the velocity of the electro-osmotic flow has to fulfill the following requirements. The compound must be soluble in the electrolyte solution and neutral in a wide pH range and no interaction with the capillary wall must occur. In addition, the electrically neutral marker substance should be easily detectable in order to allow a small amount to be injected. If the electrically neutral marker interacts with the capillary wall or becomes partially charged by complexation with the components of the electrolyte solution, the measured electro-osmotic velocity may appear slower or faster than the real flow. Some compounds that adequately serve as electrically neutral markers include benzyl alcohol, riboflavin, acetone, dimethyl-formamide, dimethyl sulfoxide, and mesityl oxide. 

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