Analysis citric acid

Spiral woimd module of 1 m effective separation area of thin film composite (TFC) Polyamide RO membrane was fabricated with the help of Permion-ics Membranes Pvt. Ltd., Vadodara, India, /w-phenylenediamine (MPD) and trimesoyl chloride (TMC) obtained from AVRA Synthesis Pvt. Ltd (Hyderabad, India) were used without further purification. Piperazine was purchased from Sigma-Aldrich, USA. Groimd water samples collected from two different places of Andhra Pradesh (A.P.), India was used for experimental trials. Potassium dichromate, ferrous ammonium sulfate, mercuric sulfate, sulfuric acid, ferroin indicator for COD analysis, sodium thiosulfate, Wrinkler s reagent, MnSO, potassimn iodide, starch indicator for BOD analysis, citric acid, HCl, EDTA, NaOH, and sodium metabisulphite (SMBS) for washing the membranes were purchased from SD Fine Chemicals Ltd., Mumbai, India. Deionized water for cleaning and feed preparation was generated from the same RO system. BOD incubator (RCI-S.NO-313 India), COD incubator... 

Wagner s solution (phosphate rock analysis) dissolve 25 g citric acid and 1 g salicylic acid in water, and make up to 1 liter. Twenty-five to fifty milliliters of this reagent prevents precipitation of iron and aluminum. 

Krzek et al. [35] reported the qualitative identification and quantitative analysis of the mixtures of OTC, tiamulin, lincomycin, and spectinomycin in the veterinary preparations by using TLC/densitometry. As stationary phase, they used precoated TLC aluminum sheets, and the mobile phases were mixtures of 10% citric acid solution, hexane, ethanol (80 1 1, v/v), and n-butanol, ethanol, chloroform, 25% ammonia (4 5 2 5, v/v). The other application of TLC or HPTLC for analyzing OTC in the various samples is summarized in Table 2 [36]. 

Citric acid and nitriloacetic acid (NTA) lanthanide complexes were used in the earliest ion exchange separations of lanthanides from fission product mixtures (Kf = 3.2 for Ce(H3 Cit.)3 and Kf = 10.8 for CeNTA2) (Sillen and Martell, 1964). More recently such polyamino-polycarboxylic acids as ethylenediaminetetraacetic acid (EDTA), 1,2-diaminocyclohexaneacetic acid (DCTA), and diethylenetriaminepentaacetic acid (DTPA) have been prepared. Their lanthanide complexes are very stable (Table 3) and have been widely used in analysis and separation of lanthanide mixtures. They have also been used experimentally to remove internally-deposited 144Ce and other radioactive lanthanide nuclides from animals and man (Foreman and Finnegan, 1957 Catsch, 1962 Balabukha et al., 1966 Palmer et al., 1968 among others). 

In similar work, Sturgeon et al. [125] compared direct furnace methods with extraction methods for cadmium in coastal seawater samples. They could measure cadmium down to 0.1 pg/1. They used 10 pg/1 ascorbic acid as a matrix modifier. Various organic matrix modifiers were studied by Guevremont [116] for this analysis. He found citric acid to be somewhat preferable to EDTA, aspartic acid, lactic acid, and histidine. The method of standard additions was required. The standard deviation was better than 0.01 pg/1 in a seawater sample containing 0.07 pg/1. Generally, he charred at 300 °C and atomised at 1500 °C. This method required compromise between char and atomisation temperatures, sensitivity, heating rates, and so on, but the analytical results seemed precise and accurate. Nitrate added as sodium nitrate delayed the cadmium peak and suppressed the cadmium signal. 

Widespread medicinal use of colloidal bismuth subcitrate (CBS) has prompted extensive studies of bismuth compounds involving the citrate anion. Bismuth citrate is essentially insoluble in water, but a dramatic increase in solubility with increasing pH has been exploited as a bio-ready source of soluble bismuth, a material referred to as CBS. Formulation of these solutions is complicated by the variability of the bismuth anion stoichiometry, the presence of potassium and/ or ammonium cations, the susceptibility of bismuth to oxygenation to Bi=0, and the incorporation of water in isolated solids. Consequently, a variety of formulas are classified in the literature as CBS. Solids isolated from various, often ill-defined combinations of bismuth citrate, citric acid, potassium hydroxide, or ammonium hydroxide have been assigned formulas on the basis of elemental analysis data or by determination of water and ammonia content, but are of low significance in the absence of complementary data other than thermal analysis (163), infrared spectroscopy (163), or NMR spectroscopy (164). In this context, the Merck index lists the chemical formula of CBS as KgfNHJaBieOafOHMCeHsCbh in the 11th edition (165), but in the most recent edition provides a less precise name, tripotassium dicitrato bismuthate (166). 

This technique has been established for many years particularly for water, soil and feeding-stuff analysis, where a large number of analyses are required for quality control or monitoring purposes. A number of applications have been published for food additives including aspartame (Fatibello et al., 1999), citric acid (Prodromidis et al., 1997), chloride, nitrite and nitrate (Ferreira et al., 1996), cyclamates (Cabero et al., 1999), sulphites (Huang et al., 1999 AOAC Int, 2000), and carbonate, sulphite and acetate (Shi et al., 1996). Yebra-Biumm (2000) reviewed the determination of artificial sweeteners (saccharin, aspartame and cyclamate) by flow injection. 

There is increasing interest in the use of specific sensor or biosensor detection systems with the FIA technique (Galensa, 1998). Tsafack et al. (2000) described an electrochemiluminescence-based fibre optic biosensor for choline with flow-injection analysis and Su et al. (1998) reported a flow-injection determination of sulphite in wines and fruit juices using a bulk acoustic wave impedance sensor coupled to a membrane separation technique. Prodromidis et al. (1997) also coupled a biosensor with an FIA system for analysis of citric acid in juices, fruits and sports beverages and Okawa et al. (1998) reported a procedure for the simultaneous determination of ascorbic acid and glucose in soft drinks with an electrochemical filter/biosensor FIA system. 

The criteria for gene displacement in this study were strict. The reactions catalyzed were required to have the same EC (Enzyme Commission) number, which implies that the same cofactors had to be involved. In the example of reactions involved in the citric acid cycle given previously, when only the carbohydrate substrate and product of the reaction were the same, we could identify gene displacements at 6 of the 11 steps included in the analysis. Only two of those (malate dehydrogenase and fumarase) met the criteria in Galperin et al. (1998). 

Introduction of photoelectric cells led to the replacement of the Duboscq colorimeter and so to quantitative spectrophotometric methods of analysis which met biochemical requirements. This introduction of spectrophotometry as a routine procedure was one of the earliest technological advances underpinning the elucidation of biochemical pathways between 1930-1960. Micromanometric methods also became available about the same time, and offered a means to measure cell respiration. Manometry was developed in Warburg s laboratory in Berlin and was one of the main techniques used by H.A. Krebs in his studies on the citric acid and urea cycles (Chapters 5 and 6). 

I 6 Aspects of Mechanisms, Processes, and Requirements for Zeolite Separation Table 6.2 Analysis of citric acid product by adsorption. 

Recognizing the need for a more economically and environmentally friendly citric acid recovery process, an adsorptive separation process to recover citric acid from fermentation broth was developed by UOP [9-14] using resin adsorbents. No waste gypsum is generated with the adsorption technique. The citric acid product recovered from the Sorbex pilot plant either met or exceeded all specifications, including that for readily carbonizable substances. An analysis of the citric acid product generated from a commercially prepared fermentation broth is shown in Table 6.2, along with typical production specifications. The example sited here is not related to zeolite separation. It is intent to demonstrate the impact of adsorption to other separation processes. 

Before the availability of artificial fertilizers in the mid-19th century, farms were traditionally organic, with recycling of animal waste, and perhaps with the application of lime on acid soils. Agricultural chemical analysis may have begun with Carl Wilhelm Scheele (1742-1786), the Swedish pharmacist who isolated citric acid from lemons and gooseberries and malic acid from apples. In France, Nicolas Theodore de Saussure (1767-1845) studied the mineral composition of plant ash, and in Britain, Sir Humphrey Davy... 

---