Liquid Chromatography Lab

According to the results, the columns of caffeine in figure 1, of this experiment the hypothesis for caffeine is partially accepted. There is an increasing trend in the change of pulsation rates with increasing

Many manufactures release the caffeine content of their products publically, but not always, and new products and flavors are continuously introduced to the market. If quality checks are not performed, manufactures may alter the caffeine and benzoic acid content to suit the demands without public knowledge. To ensure the levels of caffeine and benzoic acid in products do not exceed the established safe limits and to inform the public of the amount of these compounds being consumed, various methods of analysis have been performed. Before the introduction of modern techniques, spectrophotometric methods alone were used to determine concentration of a compound in a mixture.6 The caffeine content in coffee, tea, soft drink, and energy drinks were determined using an immunoassay.7 The caffeine content in mixtures also used to have to be extracted before quantification.8

Caffeine is a wildly use drug in today’s society. Caffeine is a methylated xanthine which acts as a mild central nervous system stimulant (MS & RL, 2001). It is a stimulant which acts upon the central nervous system and increases alertness, wakefulness and restlessness and it increases the release of catecholamine from renal medullar (Fernandez, 2016; Collines, 2007). It is present in many beverages. Caffeine is found in coffee, tea, soft drinks, products containing chocolate (cocoa) and some medication (Collines, 2007). It is used as a cardiac and respiratory stimulant (Collines, 2007).Caffeine is the most frequently ingested pharmacologically active substance in the world (Collines, 2007).

Which one of the statements concerning valence bond (VB) and molecular orbital (MO) bond theories is correct?

An independent samples t-test was conducted to examine the difference between experimental conditions on test performance. The results indicated a significant difference between participants who consumed the caffeinated beverage and participants who did not, with participants in the caffeinated group (M = 7.64, SD = 2.41) performing worse than participants in the non-caffeinated group (M = 9.81, SD = 3.16), t (97) = 2.14, p < .05.

Components containing caffeine were composed into stock solutions. These solutions were diluted to 1: 10 substance: mobile phase. A stock solution of caffeine was diluted 1:50. A sequence of diluted caffeine solutions were prepared for use as a standard (ppm): 1, 2, 4, and 10. Solutions of acetaminophen, acetylsalicylic acid, and Goody’s Powder were developed to differentiate chromatographic peaks observed. These solutions were subjected to HPLC for examination of the observed peak area and retention time for the set of compounds. Comparison of retention time allowed for the differentiation of peaks observed. The peak area obtained was utilized to determine the relative concentration of caffeine present in Goody’s Powder based on the relationship obtained in the standard. The content of caffeine present in Goody’s Powder by percent weight was identified.

Coffee urine osmolality followed the same trend as control urine osmolality by remaining constant with increasing post-consumption time. Soda urine osmolality differed from control urine osmolality and soda urine osmolality by decreasing with post-consumption time. Also, soda urine osmolality was lower than both control urine osmolality and coffee urine osmolality at all collections times. Coffee heart rate followed same trend of control heart rate by generally decreasing with post-treatment time. Soda heart rate differed from control heart rate and coffee heart rate by increasing with post-consumption time. Coffee heart rate was significantly higher than both control heart rate and soda heart rate 30 minutes after treatments. Soda heart rate was higher than control heart rate and coffee heart rate at 60 minutes and 90 minutes after treatments. These results are important to our understanding of the effect of caffeine on the human

Chromatography is a separation technique in which the mixture to be separated is dissolved in a solvent and the resulting solution, often called the mobile phase, is then passed through or over another material, the stationary phase. The separation of the original mixture depends on how strongly each component is attracted to the stationary phase. Substances that are attracted strongly to the stationary phase will be retarded and not move alone with the mobile phase. Weakly attracted substances will move more rapidly with the mobile phase.

There are many methods in the literature about measuring the porosity of porous material29. In our experiment, straight pieces of Grade 1 chromatography paper of 20 ⅹ 1 cm2 are cut. These segments are laminated to reduce the evaporation effect of water and also minimize the paper swelling upon getting wet. They were first weighed dry on a sensitive weighing balance. The bottom section of the laminated film is open, and the paper strips are dipped into water and oleic acid in a vertical position. The top of the laminated section is pierced to allow atmospheric pressure to act on both the sides and therefore not increasing the pressure increase inside the film as shown in Figure 1A.

Thin-layer chromatography (TLC) is a chromatography technique used to separate the components of a mixture. It can be used to monitor the progress of a reaction, determine the purity of a substance, and identify compounds present in a given mixture. TLC is performed on a sheet of glass, plastic, or aluminum foil, which is coated with a thin layer of adsorbent material, usually silica gel, aluminum oxide, or cellulose. This layer of adsorbent is known as the stationary phase. After the sample has been applied on the plate, a solvent or solvent mixture is drawn up the plate via capillary action (known as the mobile phase).

Introduction/Procedure: Thin Layer Chromatography (tlc) is a technique used to separate two or more compounds or ions, using a think later or material made out of silica gel on a glass or plastic plate. There are two phases that contribute, the mobile and stationary phase, the mobile phase is when the molecule in solution has to decide to stay in the solution and the stationary phase is when the solution decides to adhere to the solid. Thin layer chromatography is convenient and used for fast qualitative analysis and is very important in organic chemistry because it helps establish the number of components in a mixture and allows us to conclude if two compounds are identical. Chromatography is additionally a green method; the materials such as the tlc plates and the capillary tubes are inexpensive and easily accessible.

Ever stay up late studying for a test or exam and wake up exhausted? Or just experienced a long day and need an extra boost? Many people believe caffeine is the answer to anyone’s drained state of being. Healthline.com explains that, “Caffeine reaches your brain quickly and acts as a central nervous system stimulant.” Caffeine is commonly referred to the most widely used drug on the planet, so the next question is which caffeine-filled product is the most efficient? It is widely debated whether energy drinks or coffee can provide the best balance of caffeine, flavor, and other ingredients, but after researching, I have come to conclude coffee is superlative in all aspects.

The metabolism results of study A showed caffeine results (Fig. A) as expected. Pre-caf gave the earliest caffeine reading, followed by dur-caf. Urinary caffeine levels (Fig. B) were well below the International Olympic Committee regulation of 12µg/ml. Plasma analysis showed that blood glucose levels were higher in the pre-caf treatment, possibly due an increase in metabolic rate from the

Chromatography Investigation Chromatography is a highly regarded technique used to separate the components of a mixture. It is based on the principle that each component possesses a unique affinity for a stationary phase and a mobile phase. The components that are more inclined to enter the mobile phase will migrate further on the chromatogram and distinguish themselves from the other components. The type of solvent used in chromatography is known to directly affect the separation of the mixture. In this experiment, thin-layer and column chromatography will be utilized to separate the numerous chlorophyll and carotenoid pigments of a spinach extract.

A simple, selective and precise stability indicating isocratic reversed-phase high-performance liquid chromatographic method (RP-HPLC) was developed for the determination of buprenorphine hydrochloride in pharmaceutical microemulsion formulation. A forced degradation study of buprenorphine hydrochloride microemulsion formulation was carried out in accordance with International Conference on Harmonization (ICH) guidelines Q1 (R2). The chromatogram was obtained with 10 mmolL−1 potassium phosphate buffer adjusted to pH 6.0 with triethanolamine and acetonitrile (17:83, v/v) as mobile phase, a C-18 column; PrincetonSPHER -100 C18 HPLC column (250 × 4.6 mm i.d., 5 µm) kept at 30◦C and UV detection at 284 nm. The compound was eluted isocratically at a flow rate of 1.0 mL min−1. The average retention time for buprenorphine was 14.319 min. The method was validated according to the ICH guidelines. The validation characteristics included accuracy, precision, linearity, range, specificity, limit of Quantitation and robustness. The calibration curves were linear (R2 > 0.999) over the concentration range 1.0 – 500.0 µgmL−1 for buprenorphine hydrochloride and the recovery study for the compound was above 95 %. No spectral or chromatographic interferences from the microemulsion excipients were found. The drug was found to be labile under oxidative stress condition; whereas, it was stable under all other stress conditions. This method is rapid and simple and does not require any sample