Paper chromatography quantitative

Lactic Acid. Qualitative and even semiquantitative data are obtained by paper chromatography. Quantitative procedures where lactic acid is oxidized to acetaldehyde and the acetaldehyde determined colorimetri-cally are available (4,13, 22, 90). 

Until the advent of paper chromatography, quantitative analysis of sugar mixtures, except of those of simple composition, was both difficult... 

Paper chromatography, quantitative, transition metals, ascending development. 

For the more advanced student, we have extended the section on Quantitative Semi-micro Analysis, and we have included a section dealing with Special Techniques in Separation and Purification, namely Adsorption Chromatography, Paper Chromatography, and Ion- Exchange Processes. 

Gas-flow counting is a method for detecting and quantitating radioisotopes on paper chromatography strips and thin-layer plates. Emissions are measured by interaction with an electrified wire in an inert gas atmosphere. AH isotopes are detectable however, tritium is detected at very low (- 1%) efficiency. 

Specifications, Analysis, and Toxicity. Dicyandiamide is identified quaHtatively by paper chromatography and quantitatively by ultraviolet spectrometry of the chromatogram. More commonly, total nitrogen analysis is used as a purity control or the dicyandiamide is converted by hydrolysis to guanylurea, which is determined gravimetrically as the nickel salt (50). Methods based on the precipitation of silver dicyandiamide picrate are sometimes used (51). Dicyandiamide can also be titrated with tetrabutylammonium hydroxide ia pyridine solution. Table 4 gives a typical analysis of a commercial sample. Dicyandiamide is essentially nontoxic. It may, however, cause dermatitis. 

High Pressure Liquid Chromatography. This modem version of the classical column chromatography technique is also used successfully for separation and quantitative analysis of dyes. It is generally faster than thin-layer or paper chromatography however, it requires considerably more expensive equipment. Visible and uv photometers or spectrophotometers are used to quantify the amounts of substances present. 

Chromatography is one of the most powerful and widely used means for separating mixtures, because it is often inexpensive and it can be used to provide quantitative as well as qualitative information. The simplest method is paper chromatography. A drop of solution is placed near the bottom edge of the stationary phase, an absorbant support, such as a strip of paper. The mobile phase, a fluid solvent, is added below the spot and the solvent is absorbed on the support. As the mobile phase rises up the stationary phase by capillary... 

The development of the open-column methods, ie paper chromatography (in the 1940 s) and thin-layer chromatography (in the 1950 s) greatly improved the speed and resolution of lc, but there were still serious limitations compared to modern lc methods, in that analysis times were long, resolution was poor and quantitative analysis, preparative separations and automation were difficult. 

To determine the relative amounts of neomycins B, C and neamine by a radio chemical method, Kaiser 2 separated the -labelled N-acetyl derivatives by paper chromatography and quantitated the chromatograms by liquid scintillation counting. A coefficient of variation of 3.6% was obtained. 

The column chromatography technique using Dowex 50 ion-exchange resin, introduced in 1951 (M2) and improved in 1954 (M3) by Moore and Stein, first made possible the precise quantitative analysis of amino acids liberated in the course of acid hydrolysis of urine. Similar results were also obtained by Muting in 1954 (M4), who used paper chromatography methods. In this procedure amino acids were quantitatively determined after staining on the paper and elution of the resulting spots. 

Quantitative analysis is also possible. The spot representing the component of interest can be cut (in the case of paper chromatography) or scraped from the surface (TLC), dissolved, and quantitated by some other technique, such as spectrophotometry. Alternatively, modern scanning densitometers, which utilize the measurement of the absorbance or reflectance of ultraviolet or visible light at the spot location, may be used to measure quantity. 

The anthocyanin profile of the flowers of Vanda (Orchidaceae) was investigated with a similar technique. Flowers (2 kg) were extracted with 101 of methanol-acetic acid-water (9 l 10,v/v) at ambient temperature for 24 h. The extract was purified by column chromatography, paper chromatography, TLC and preparative RP-HPLC. Analytical HPLC was carried out in an ODS column (250 X 4.6 mm, i.d.) at 40°C. Gradient conditions were from 40 per cent to 85 per cent B in 30 min (solvent A 1.5 per cent H3P04 in water solvent B 1.5 per cent H3P04, 20 per cent acetic acid and 25 per cent ACN in water). The flow rate was 1 ml/min and analytes were detected at 530 nm. The chemical structures of acylated anthocyanins present in the flowers are compiled in Table 2.90. The relative concentrations of anthocyanins in the flower extracts are listed in Table 2.91. It can be concluded from the results that the complex separation and identification methods (TLC, HPLC, UV-vis and II NMR spectroscopy, FAB-MS) allow the separation, quantitative determination and identification of anthocyanins in orchid flowers [262],... 

Since the labeling technique was introduced, a large number of further publications on the paper chromatography of phosphates have appeared (159), but these papers will not be considered separately here. They serve to confirm what was already partly known, and they describe improvements in technique, thereby reducing the risk of hydrolysis of the condensed phosphates in the acid medium used in chromatography. They also show how the accuracy of quantitative analysis could be increased (226). 

Highly condensed polyphosphates, which cannot be separated by paper chromatography may be separated into groups by paper electrophoresis 255). Paper chromatography allows the complete separation and quantitative determination of all condensed phosphates with n up to 10, but its use is limited to 7-quantities. 

Solvent extraction by tributyl phosphate (TBP) (13, 96), dithizone (20, 71, 72), cupferron (89), thenoyl trifluoroacetone (TTA) (55), diiso-propyl ketone (26), mesityl oxide (92), tri-n-benzylamine and methyl di-n-octylamine (99), diisopropyl and diisobutyl carbinol (100) have all found some application on the trace scale. Acetylaeetone and methyl isobutyl ketone extract milligram amounts of polonium almost quantitatively from hydrochloric acid, but the stable polonium-organic compounds which are formed make it difficult to recover the polonium in a useful form from solutions in these ketones (7). Ion exchange (22, 115, 119) and paper chromatography (44, 87) have also been used for trace scale separations of polonium, but the effects of the intense alpha-radiation on organic com-... 

Malic Acid. This is seldom determined quantitatively in winery practice. However, qualitative paper chromatography is often done to follow malo-lactic fermentation. Using n-butyl alcohol and formic acid (80), the Rf values are tartaric 0.28, citric 0.45, malic 0.51, ethyl acid tartrate 0.59, lactic acid 0.78, succinic 0.78, and ethyl acid malate 0.80. 

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