Stock solutions, dilution

An agricuiturai chemist wished to study the effect of varying fertilizer applications on the growth of tomato piants. The chemist prepared a stock aqueous solution of urea, (NH2)2 CO, by dissolving 1.75 g of this compound in water to make 1.00 L of solution. Then she prepared a series of more dilute solutions to apply to her tomato plants. One of these solutions contained 5.00 mL of stock solution diluted to give a final volume of 25.00 mL. What was the concentration of urea in this diluted solution ... 

Prepare calibration standards of the selected metal, with concentrations suggested by your instructor, from a 1000 ppm stock solution. Dilute each to the mark with distilled water and shake well. 

Secondary antibody usually fluorescent antimouse conjugate, stock solution diluted 1 20-1 500 in PBSG with 10% bovine serum albumin see Note 1). 

The manual procedure for determination of total nitrogen by chemiluminescence involves preparing the standards from a stock solution, diluting the samples, injecting the standards into the combustion furnace for analysis, and calculation of the nitrogen content of the samples. The calculation is based on the signal from the diluted sample compared to the standard curve and the dilution factor for the sample. 

Tris-bufifered saline (TBS) Weigh 24.2 g Tris base (0.2 M), 87.8 g NaGl (1.5 M), adjust pH to 7.4, and make up to 1,000 ml with distilled water to give a lOx TBS stock solution. Dilute the stock solution to lx with distilled water before use. 

Cloprostenol (Estrumate), 250 Xg/mL stock solution, diluted 1 31 in Aqua dest. (for induction ofluteolysis in marmosets). 

The standard is composed of a series of n-alkanes, from C7 to C30. They should be dissolved in the same solvent that is used for dissolving the sample being analyzed. A suitable concentration is 100 ig/ml of each one, with two, e.g., Cu and C13, at a concentration of 50 pg/ml to act as markers in the chromatogram. This stock solution should be stored at —10°C to minimize loss of low molecular weight alkanes and used as a stock solution. Dilute it by 1 10 for use as a standard. A convenient procedure for making up the stock solution follows. 

Samples of technical chlorobenzilate (97.0%) and dicofol (87.6%) were diluted to known concentrations with ethyl alcohol. From the stock solutions, dilutions were made in Mazda corn oil for oral dosing. Solutions for dermal application remained in ethanol. The concentrations on an active ingredient basis were ... 

Standard Stock Solution 1 Transfer about 25 mg of benzoic acid reference standard, accurately weighed, to a 250-mL volumetric flask, add 5.0 mL of Stock Solution, dilute with Mobile Phase to volume, and mix. 

Prepare a stock solution of NADH equal to 11 mM. In a test tube, add 100 pi of the NADH solution, different volumes of pyruvate stock solution, and 40 pi of LDH stock solution diluted 100 times, and then make up the quantity to 3 ml with phosphate buffer. After mixing the solution, measure the optical density at 340 nm after 2 min reaction. The pyruvate volumes to be added are shown in Table 3.1. 

Aliquots of the stock solution diluted to 10 pM are added to 1 mL of pH-adjusted plasma, protein fraction or buffer. The amount of organic content should not exceed more than 2 % of the initial spiked plasma. Higher content could adversely interfere with protein binding. 

Sample Preparation Transfer about 1 g of sample, accurately weighed, into a 10-mL volumetric flask, add 2.00 mL of Methyl Benzoate Stock Solution, dilute to volume with pyridine, and mix. Prepare a trimethylsilyl derivative as described under Calibration Standards (above). 

Standard p-Nitroaniline Solutions Prepare the following dilutions of p-Nitroaniline Stock Solution dilute 1 mL of p-Nitroaniline Stock Solution to 100 mL with pH 7.0 Phosphate Buffer (Solution 1, 0.01136 mM) dilute 9 mL of Solution 1 with 3 mL of pH 7.0 Phosphate Buffer (Solution 2, 0.00852 mM) and dilute 5 mL of Solution 1 with 5 mL of pH 7.0 Phosphate Buffer (Solution 3, 0.00568 mM). 

Neutral red (4 mg mH stock solution) dilute 1 100 into medium, incubate overnight at 37°C and centrifuge before use... 

Phalloidin-DAPI Staining of Embryos 1. Phalloidin-Rhodamine or Phalloidin-Fluorescein (Invitrogen, Molecular Probes, Carlsbad, CA) 6.6 J.M stock solution diluted 1 500 in PBTA (freshly diluted and kept in the dark). 2. DAPI (Molecular Probes) 100pM stock solutions diluted 1 2,000 in PBTA (freshly diluted and kept in the dark). 

For work exclusively on oceanic waters, the calibration factor is determined using standard stock solutions diluted with natural seawater low in ammonia. Proceed as described above. In this case, the value of F should be close to 6.0 with a 10 cm cell. 

Buffer 2 Dissolve 10 g of the blocking reagent provided in the Genius 3 detection kit (Boehringer Mannheim) in buffer 1 by heating and store at -20°C (stock solution). Dilute the stock solution 1.5 (v.v) in buffer 1 Buffer 3 Mix 100 mL of 1 M Tris-HCl, 20 mL of 5 M NaCl, and 50 mL of I M MgCl2 with 800 mL of DEPC-treated water, adjust the pH to 9 5 and add water to a volume of 1 L The buffer can be filtered with Whatman No 1 filter if precipitation occurs... 

A student wants to prepare 0.600 L of a stock solution of copper(II) chloride so that 20.0 mL of the stock solution diluted by adding 130.0 mL of water will yield a 0.250 M solution. What mass of CUCI2 should be used to make the stock solution ... 

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