2- -ethanesulfonic acid

Sulfonic acids are such strong acids that in general they can be considered greater than 99% ionized. The piC value for sulfuric acid is —2.8 as compared to the piC values of —1.92, —1.68, and —2.8 for methanesulfonic acid, ethanesulfonic acid, and benzene sulfonic acid, respectively (3). Trifluoromethanesulfonic acid [1493-13-6] has a piC of less than —2.8, making it one of the strongest acids known (4,5). Trifluoromethanesulfonic acid is also one of the most robust sulfonic acids. Heating this material to 350°C causes no thermal breakdown (6). 

AACC Method32-07for TDF, SDF, and IDF. This approved method is a modification of the Prosky method. The phosphate buffer is replaced by a buffer of 2(A[-morpholino)ethanesulfonic acid (MES) [4432-31-9] and tris(hydroxymethyl)aminomethane (TRIS) [77-86-1]. Precision is improved and analysis time is reduced. I DE may be determined on a separate sample or calculated by summing the SDE and IDE values. The MES /TRIS-modified method has received final approval by AACC and official first action by AO AC (5). 

Heavy metal contamination of pH buffers can be removed by passage of the solutions through a Chelex X-100 column. For example when a solution of 0.02M HEPES [4-(2-HydroxyEthyl)Piperazine-l-Ethanesulfonic acid] containing 0.2M KCl (IL, pH 7.5) alone or with calmodulin, is passed through a column of Chelex X-100 (60g) in the K" " form, the level of Ca ions falls to less than 2 x 10" M as shown by atomic absorption spectroscopy. Such solutions should be stored in polyethylene containers that have been washed with boiling deionised water (5min) and rinsed several times with deionised water. TES [, N,N, -Tetraethylsulfamide] and TRIS [Tris-(hydroxymethyl)aminomethane] have been similarly decontaminated from metal ions. 

V-2-Hydroxyethylpiperazine-7V -2-ethanesulfonic acid (HEPES) [7365-45-9] M 238.3, pK 7.55. Crystd from hot EtOH and water. 

Sulfurous acid has never been isolated as a pure compound, although it has recently been detected in the gas phase by neutralization reionization mass spectrometry (NRMS) following the facile dissociative ionization (70 eV) of either diethyl sulfite or ethanesulfonic acid " ... 

Figure 2 Stability of /3-poly(L-malate) measured by its activity to inhibit purified DNA polymerase a of P. polyceph-alum. The relative degree of inhibition is shown (100 rel. units refer to complete inhibition). The DNA polymerase assay was carried out in the presence of 5 /tg/ml /S-poly(L-malate) as described [4]. The polymer was preincubated for 7 days at 4°C in the following buffer solutions (50 mM) KCl/HCl (—A—). Citrate (—V—). 2-(A/-Morpholino)-ethanesulfonic acid, sodium salt (—O—). Sodium phosphate (— —). N-(2-Hydroxyethyl)piperazine-N -(2-ethanesul-fonic acid), sodium salt (— — ). N,N-b s (2-Hydroxyethyl)-glycine, sodium salt (—T—). Tris/HCl (— —). 3-(Cyclo-hexylamino)-l-propanesulfonic acid, sodium salt (— —).

N-(2-FFydroxyl)piperazine-N,-(2-ethanesulfonic acid) High performance liquid chromatography Intensity... 

The method for chloroacetanilide soil metabolites in water determines concentrations of ethanesulfonic acid (ESA) and oxanilic acid (OXA) metabolites of alachlor, acetochlor, and metolachlor in surface water and groundwater samples by direct aqueous injection LC/MS/MS. After injection, compounds are separated by reversed-phase HPLC and introduced into the mass spectrometer with a TurboIonSpray atmospheric pressure ionization (API) interface. Using direct aqueous injection without prior SPE and/or concentration minimizes losses and greatly simplifies the analytical procedure. Standard addition experiments can be used to check for matrix effects. With multiple-reaction monitoring in the negative electrospray ionization mode, LC/MS/MS provides superior specificity and sensitivity compared with conventional liquid chromatography/mass spectrometry (LC/MS) or liquid chromatography/ultraviolet detection (LC/UV), and the need for a confirmatory method is eliminated. In summary,... 

Ethanesulfonic acid, 2-[(ethoxymethyl)[2-(l-hydroxyethyl)-6-methylphenyl] amino]-2-OXO-, sodium salt, hydrate (1 1), should be >95% pure (HEMA-producing sulfonic acid metabolite, referred to from this point as Metabolite II)... 

Chromatography by ion exchange on a sulfonated poly(styrene-co-divinyl benzene) phase has been proposed as a replacement for titrimetry.57 Eluted by a dilute solution of a neutral salt such as sodium ethanesulfonate, the conductance of the protons can be measured in the absence of a suppressor from sub-millimolar to molar concentration. The response factors of mono-, di-, and trichloroacetic acid and of o-phthalic acid were large and essentially equivalent to ethanesulfonic acid, while the response factor of acetic acid was far smaller. A syringe pump has generated pressures as high as 72,000 psi (5000 bar) in a capillary column packed with 1 p particles, generating a fraction capacity of 300 peaks in 30 minutes.58... 

Carolina in 1981. Each sample (1.4 ml of methanolic sample) was placed into a 3-cm petri dish and the solvent evaporated under a laminar flow hood at room temperature. Seventy seeds (0.035 g) were then placed into the petri dishes and 1.4 ml of sterilized (0.2 pm-filter) 15 mM Mes [2-(N-morpholino)ethanesulfonic acid Sigma Chemical Co.] buffer adjusted to pH 5.5 was added. The dishes were kept in the dark at 25°C2for 84 hr, exposed to 12-hr fluorescent light (250 p einsteins/m /sec), and then placed back in the dark for an additional 4 days (17). Percent germination, root and hypocotyl lengths were then determined. 

Roy, R. N. Gihhons, J. J. Padron, J. L. Moeller, J., Second-stage dissociation constants of piperazine-A,A -bis(2-ethanesulfonic acid) monosodium monohydrate and related thermodynamic functions in water from 5 to 55°C, Anal. Chem. 52, 2409-2412 (1980). 

N-2-hydroxyethyl-piperazine-N -2-ethanesulfonic acid High-throughput screening... 

Dissolve the protein to be modified at a concentration of 5-10mg/ml in 20 mM TES, pH 7.0. TES is 2-[[tris(hydroxymethyl)methyl]amino]ethanesulfonic acid. 

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