Glycolic acid, detection

The first catalysts reported for the electroreduction of C02 were metallophthalocyanines (M-Pc).126 In aqueous solutions of tetraalkylammonium salts, current-potential curves at a cobalt phthalocyanine (Co-Pc)-coated graphite electrode showed a reduction current peak whose height was proportional to the C02 concentration and to the square root of the potential sweep rate at a given C02 concentration. On electrolysis, oxalic acid and glycolic acid were detected, but formic acid was not. Mn and Pd phthalocyanines were inactive, while Cu and Fe phthalocyanines were slightly active. At the potentials used for C02 reduction, M-Pc catalysts would be in their dinegative state, and the occupied dz2 orbital of the metal ion in the metallophthalocyanine was suggested to play an important role in the catalytic activity. 

Reeder and Rieger6 used ESR spectra to identify complex ions and to estimate formation constants for aqueous oxovanadium(iv) complexes with lactic acid, thiolactic acid, glycolic acid, and thioglycolic acid. Through the use of second-harmonic detection, which produces second-derivative spectra, the resolution was good enough that several of the individual species could be separately... 

Two tests were used for the detection of glycolic acid the chromatropic acid test and the method whereby the glycolic acid is treated with sulfuric acid and the resulting carbon monoxide detected by phosphomolybdic acid-palladium chloride reagent (10, 12). 

With a 1 1 molar ratio of ethylene glycol and H2O2, the selectivity to glycolic acid was 86% at 44% conversion of the glycol and 99% conversion of the H202. Small amounts of glyoxylic acid (3%) and formic acid were also detected. 

The TEWL values decreased significantly within 15 days on both sites, particularly for the corticosteroid treated site (P <. 01 glycolic, P <. 005 betamethasone). However, no significant differences in TEWL between glycolic acid and betamethasone could be detected. 

Fig. 3-84. Separation of various monocarboxylic acids at an anion exchanger IonPac AS6 (CarboPac). - Eluent 0.0017 mol/L NaHCOj + 0.0018 mol/L Na2C03 flow rate 1 mL/min detection suppressed conductivity injection 50 pL solute concentrations 3 ppm fluoride (1), 40 ppm acetic acid (2), 20 ppm glycolic acid (3), 10 ppm a-hydroxyisocaproic acid (4), 20 ppm formic acid (5), oxamic acid (6), methanesulfonic acid (7), amidosulfonic acid (8), and a-ketoisocaproic acid (9).

In six men exposed one-arm only to 50 ppm [ 2] 2-butoxyethanol for 2 hours, about two-thirds of the 2-butoxyacetic acid excreted in the urine was in the form of the A-butoxyacetyl glutamine conjugate (Corley et al. 1997). No free 2-butoxyethanol, free or conjugated ethylene glycol ether, or glycolic acid (a metabolite of ethylene glycol) were detected in the urine. 2-Butoxyacetic acid was eliminated in the urine primarily during the first 12-hour collection period. 

The reaction was performed under the fixed reaction conditions described in the Experimental section, while changing the contact time from 0.3 to 5.0 s. The main products detected were glyoxylic acid, formaldehyde, formic acid, and carbon oxides. The yields of these products are plotted as a function of the conversion of glycolic acid in Figure 1. The slope of lines from the origin indicate the selectivities to each product. 

It is unfortunate, however, that the analytical method for the determination of glycolic acid (Shah and Fogg, 1973) is far too insensitive and perhaps not reproducible enough to detect low-level excretion in situ. It is also unlikely that information may be derived from studies involving the determination of bulk parameters (e.g. DOC) leading to an estimate of the extent of natural excretion processes. 

VEGF Rat Poly(lactic-co-glycolic) acid microspheres vs. protein solutions Subcutaneous vinjection of microspheres vs. intravenous injection of solutions VEGF in microspheres administered subcutaneously was detected with low plasma concentrations and high subcutaneous concentrations over a period of 7 weeks. VEGF in solution administered intravenously was rapidly cleared with high plasma concentrations as expressed by rapid absorption and elimination [- ]... 

US due to its ability to detect flow within vasculature on the micron level. Contrast-enhanced Doppler has proven successful in the detection and diagnosis of cancers, " detection of inflammation precursors, and brain imaging. Figure 3 shows an example of contrast-enhanced Doppler of a rabbit kidney using a poly(laaic-co-glycolic acid) (PLGA), air-filled UCA developed in our laboratory. After injection, UCAs within the kidney vasculature become apparent, providing substantial contour detection. 

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