240 research outputs found
Thermal instability of monoalkyl esters of phthalic acid during their gas chromatographic separation
ΠΠΎΠ½ΠΎΠ°Π»ΠΊΠΈΠ»ΠΎΠ²ΡΠ΅ ΡΡΠΈΡΡ Π±Π΅Π½Π·ΠΎΠ»-1,2-Π΄ΠΈΠΊΠ°ΡΠ±ΠΎΠ½ΠΎΠ²ΠΎΠΉ (ΡΡΠ°Π»Π΅Π²ΠΎΠΉ) ΠΊΠΈΡΠ»ΠΎΡΡ ΡΠ²Π»ΡΡΡΡΡ ΠΎΡΠ½ΠΎΠ²Π½ΡΠΌΠΈ ΠΏΡΠΎΠ΄ΡΠΊΡΠ°ΠΌΠΈ ΠΌΠ΅ΡΠ°Π±ΠΎΠ»ΠΈΠ·ΠΌΠ° (ΡΠ°ΡΡΠΈΡΠ½ΠΎΠ³ΠΎ Π³ΠΈΠ΄ΡΠΎΠ»ΠΈΠ·Π°) Π΄ΠΈΠ°Π»ΠΊΠΈΠ»ΡΡΠ°Π»Π°ΡΠΎΠ², ΡΠΈΡΠΎΠΊΠΎ ΠΏΡΠΈΠΌΠ΅Π½ΡΡΡΠΈΡ
ΡΡ Π² ΠΊΠ°ΡΠ΅ΡΡΠ²Π΅ ΠΏΠ»Π°ΡΡΠΈΡΠΈΠΊΠ°ΡΠΎΡΠΎΠ² ΠΏΠΎΠ»ΠΈΠΌΠ΅ΡΠ½ΡΡ
ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡΠΈΠΉ. ΠΡΠΎΠ²Π΅ΡΠΊΠ° Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΠ΅ΠΉ Π³Π°Π·ΠΎΡ
ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΈ Ρ
ΡΠΎΠΌΠ°ΡΠΎ-ΠΌΠ°ΡΡ-ΡΠΏΠ΅ΠΊΡΡΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ Π°Π½Π°Π»ΠΈΠ·Π° ΠΏΡΠΎΡΡΠ΅ΠΉΡΠΈΡ
ΠΌΠΎΠ½ΠΎΠ°Π»ΠΊΠΈΠ»ΠΎΠ²ΡΡ
(Π‘β-Π‘β) ΡΡΠΈΡΠΎΠ² ΠΏΠΎΠΊΠ°Π·Π°Π»Π°, ΡΡΠΎ ΡΡΠΈ ΡΠΎΠ΅Π΄ΠΈΠ½Π΅Π½ΠΈΡ ΡΠ΅ΡΠΌΠΈΡΠ΅ΡΠΊΠΈ Π½Π΅ΡΡΠ°Π±ΠΈΠ»ΡΠ½Ρ ΠΈ ΡΠ°Π·Π»Π°Π³Π°ΡΡΡΡ Π² Ρ
ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΊΠΎΠ»ΠΎΠ½ΠΊΠ΅, ΡΡΠΎ ΠΌΠΎΠΆΠ΅Ρ ΠΎΡΠ»ΠΎΠΆΠ½ΡΡΡ ΠΈΡ
ΠΎΠ±Π½Π°ΡΡΠΆΠ΅Π½ΠΈΠ΅ Π² ΡΠ°Π·Π»ΠΈΡΠ½ΡΡ
ΠΎΠ±ΡΠ°Π·ΡΠ°Ρ
. Π£ΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΎ, ΡΡΠΎ ΠΎΡΠ½ΠΎΠ²Π½ΠΎΠ΅ Π½Π°ΠΏΡΠ°Π²Π»Π΅Π½ΠΈΠ΅ Π΄Π΅ΡΡΡΡΠΊΡΠΈΠΈ ΠΌΠΎΠ½ΠΎΠ°Π»ΠΊΠΈΠ»ΡΡΠ°Π»Π°ΡΠΎΠ² Π² Π³Π°Π·ΠΎΡ
ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΊΠΎΠ»ΠΎΠ½ΠΊΠ΅ Π°Π½Π°Π»ΠΎΠ³ΠΈΡΠ½ΠΎ ΠΈΠ·Π²Π΅ΡΡΠ½ΠΎΠΌΡ ΠΏΡΠΎΡΠ΅ΡΡΡ ΠΈΡ
ΠΏΠΈΡΠΎΠ»ΠΈΠ·Π° Ρ ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΡΡΡΠΈΡ
ΡΠΏΠΈΡΡΠΎΠ² ΠΈ ΡΡΠ°Π»Π΅Π²ΠΎΠ³ΠΎ Π°Π½Π³ΠΈΠ΄ΡΠΈΠ΄Π°. ΠΠΎ ΡΡΠΎΠΉ ΠΏΡΠΈΡΠΈΠ½Π΅ Π΄Π»Ρ ΡΠ°Π·Π΄Π΅Π»Π΅Π½ΠΈΡ ΠΌΠΎΠ½ΠΎΡΡΠΈΡΠΎΠ² ΡΡΠ°Π»Π΅Π²ΠΎΠΉ ΠΊΠΈΡΠ»ΠΎΡΡ Π½Π΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌΠΎ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°ΡΡ ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΠΎ ΠΊΠΎΡΠΎΡΠΊΠΈΠ΅ ΠΊΠΎΠ»ΠΎΠ½ΠΊΠΈ Ρ ΡΠΎΠ½ΠΊΠΈΠΌΠΈ ΠΏΠ»Π΅Π½ΠΊΠ°ΠΌΠΈ ΡΡΠ°Π½Π΄Π°ΡΡΠ½ΡΡ
Π½Π΅ΠΏΠΎΠ»ΡΡΠ½ΡΡ
Π½Π΅ΠΏΠΎΠ΄Π²ΠΈΠΆΠ½ΡΡ
ΡΠ°Π· ΠΏΡΠΈ ΠΌΠΈΠ½ΠΈΠΌΠ°Π»ΡΠ½ΠΎΠΉ ΡΠΊΠΎΡΠΎΡΡΠΈ ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΡ, ΡΡΠΎ ΠΏΠΎΠ·Π²ΠΎΠ»ΠΈΡ ΡΠ½ΠΈΠ·ΠΈΡΡ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΡ ΡΠ΄Π΅ΡΠΆΠΈΠ²Π°Π½ΠΈΡ ΡΠ°ΠΊΠΈΡ
Π°Π½Π°Π»ΠΈΡΠΎΠ² ΠΈ, ΡΠ»Π΅Π΄ΠΎΠ²Π°ΡΠ΅Π»ΡΠ½ΠΎ, ΠΌΠΈΠ½ΠΈΠΌΠΈΠ·ΠΈΡΠΎΠ²Π°ΡΡ ΠΈΡ
ΡΠ΅ΡΠΌΠΈΡΠ΅ΡΠΊΠΎΠ΅ ΡΠ°Π·Π»ΠΎΠΆΠ΅Π½ΠΈΠ΅. ΠΡΡΠΊΠ°Π·Π°Π½ΠΎ ΠΏΡΠ΅Π΄ΠΏΠΎΠ»ΠΎΠΆΠ΅Π½ΠΈΠ΅, ΡΡΠΎ ΠΈΠΌΠ΅Π½Π½ΠΎ ΡΠ°Π·Π»ΠΎΠΆΠ΅Π½ΠΈΠ΅ Ρ ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ ΡΡΠ°Π»Π΅Π²ΠΎΠ³ΠΎ Π°Π½Π³ΠΈΠ΄ΡΠΈΠ΄Π° ΠΎΠ±ΡΡΡΠ½ΡΠ΅Ρ Π²ΡΡΠΎΠΊΡΡ ΡΠΎΠΊΡΠΈΡΠ½ΠΎΡΡΡ (Π² ΡΠΎΠΌ ΡΠΈΡΠ»Π΅ ΡΠ½Π΄ΠΎΠΊΡΠΈΠ½Π½ΡΡ) ΠΌΠΎΠ½ΠΎΠ°Π»ΠΊΠΈΠ»ΡΡΠ°Π»Π°ΡΠΎΠ² Π΄Π»Ρ ΡΠ΅Π»ΠΎΠ²Π΅ΠΊΠ° ΠΈ ΠΆΠΈΠ²ΠΎΡΠ½ΡΡ
.Monoalkyl esters of benzene-1,2-dicarboxylic (phthalic) acid are the main metabolites (products of the partial hydrolysis) of dialkyl phthalates widely used as ingredients of polymeric compositions. Testing the possibilities of GC and GC-MS analysis of the simplest monoalkyl (Cβ-Cβ) esters indicates these compounds are thermally unstable and decompose in a chromatographic column during separation that may complicate their determination. The principal way of monoalkyl phthalate decomposition is similar to the known process of their pyrolysis with formation of corresponding alkanols and phthalic anhydride. It is concluded that GC analysis of these monoesters can be provided using short WCOT columns with thin layers of non-polar stationary phases at the smooth temperature ramps. It allows to reduce retention temperature of such analytes and, hence, to minimize their thermal decomposition. It is proposed that just the possibility of phthalic anhydride formation in the result of decomposition explains us high toxicity (including endocrine disruptions) of monoalkyl phthalates for mammals
Features of the gas chromatographic analysis of aliphatic dicarboxylic acids
ΠΠ·ΡΡΠ΅Π½ΠΈΠ΅ Π»ΠΈΡΠ΅ΡΠ°ΡΡΡΠ½ΡΡ
Π΄Π°Π½Π½ΡΡ
ΡΠ²ΠΈΠ΄Π΅ΡΠ΅Π»ΡΡΡΠ²ΡΠ΅Ρ, ΡΡΠΎ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡ ΠΏΡΡΠΌΠΎΠ³ΠΎ Π³Π°Π·ΠΎΡ
ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ Π°Π½Π°Π»ΠΈΠ·Π° ΡΠ°ΠΊΠΈΡ
ΡΡΡΠ΄Π½ΠΎΠ»Π΅ΡΡΡΠΈΡ
ΠΏΠΎΠ»ΡΡΠ½ΡΡ
ΡΠΎΠ΅Π΄ΠΈΠ½Π΅Π½ΠΈΠΉ ΠΊΠ°ΠΊ Π°Π»ΠΈΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ Π΄ΠΈΠΊΠ°ΡΠ±ΠΎΠ½ΠΎΠ²ΡΠ΅ ΠΊΠΈΡΠ»ΠΎΡΡ ΠΎΡΠ»ΠΈΡΠ°ΡΡΡΡ Π·Π°ΠΌΠ΅ΡΠ½ΠΎΠΉ Π½Π΅Π²ΠΎΡΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΠΈΠΌΠΎΡΡΡΡ. ΠΠ½Π°ΡΠΈΡΠ΅Π»ΡΠ½Π°Ρ ΡΠ°ΡΡΡ ΠΎΠΏΡΠ±Π»ΠΈΠΊΠΎΠ²Π°Π½Π½ΡΡ
ΠΈΠ½Π΄Π΅ΠΊΡΠΎΠ² ΡΠ΄Π΅ΡΠΆΠΈΠ²Π°Π½ΠΈΡ ΡΡΠΈΡ
ΡΠΎΠ΅Π΄ΠΈΠ½Π΅Π½ΠΈΠΉ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΠ·ΡΠ΅ΡΡΡ ΡΡΡΠ΅ΡΡΠ²Π΅Π½Π½ΡΠΌ ΡΠ°Π·Π±ΡΠΎΡΠΎΠΌ ΠΈ ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»ΡΠ΅ΡΡΡ ΠΎΡΠΈΠ±ΠΎΡΠ½ΠΎΠΉ. ΠΠΎΠ΄ΠΎΠ±Π½Π°Ρ ΠΆΠ΅ Π½Π΅Π²ΠΎΡΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΠΈΠΌΠΎΡΡΡ ΠΏΡΠΈΡΡΡΠ° Π·Π½Π°ΡΠ΅Π½ΠΈΡΠΌ ΠΈ Π΄ΡΡΠ³ΠΈΡ
ΠΈΡ
ΡΠΈΠ·ΠΈΠΊΠΎ-Ρ
ΠΈΠΌΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΠ²ΠΎΠΉΡΡΠ² (ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ° ΠΏΠ»Π°Π²Π»Π΅Π½ΠΈΡ, ΡΠ°ΡΡΠ²ΠΎΡΠΈΠΌΠΎΡΡΡ Π² Π²ΠΎΠ΄Π΅ ΠΈ Ρ.Π΄.). ΠΡΠΏΠΎΠ»Π½Π΅Π½Π° ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Π»ΡΠ½Π°Ρ ΠΏΡΠΎΠ²Π΅ΡΠΊΠ° Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΠ΅ΠΉ Π³Π°Π·ΠΎΡ
ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΈ Ρ
ΡΠΎΠΌΠ°ΡΠΎ-ΠΌΠ°ΡΡ-ΡΠΏΠ΅ΠΊΡΡΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ Π°Π½Π°Π»ΠΈΠ·Π° ΠΏΡΠΎΡΡΠ΅ΠΉΡΠΈΡ
Π΄ΠΈΠΊΠ°ΡΠ±ΠΎΠ½ΠΎΠ²ΡΡ
ΠΊΠΈΡΠ»ΠΎΡ Π½Π° ΡΡΠ°Π½Π΄Π°ΡΡΠ½ΡΡ
Π½Π΅ΠΏΠΎΠ»ΡΡΠ½ΡΡ
ΠΏΠΎΠ»ΠΈΠ΄ΠΈΠΌΠ΅ΡΠΈΠ»ΡΠΈΠ»ΠΎΠΊΡΠ°Π½ΠΎΠ²ΡΡ
Π½Π΅ΠΏΠΎΠ΄Π²ΠΈΠΆΠ½ΡΡ
ΡΠ°Π·Π°Ρ
(BPX-1, RTX-5). Π£ΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΎ, ΡΡΠΎ Π½Π΅ΠΊΠΎΡΠΎΡΡΠ΅ ΡΠΎΠ΅Π΄ΠΈΠ½Π΅Π½ΠΈΡ ΡΡΠΎΠ³ΠΎ ΡΡΠ΄Π° (Π½Π°ΠΏΡΠΈΠΌΠ΅Ρ, Π³Π»ΡΡΠ°ΡΠΎΠ²Π°Ρ ΠΊΠΈΡΠ»ΠΎΡΠ°) ΠΎΠΏΡΠ΅Π΄Π΅Π»ΡΡΡΡΡ Π±Π΅Π· ΡΠ°Π·Π»ΠΎΠΆΠ΅Π½ΠΈΡ, Π΄Π»Ρ Π΄ΡΡΠ³ΠΈΡ
Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠ½ΠΎ Π²Π·Π°ΠΈΠΌΠΎΠ΄Π΅ΠΉΡΡΠ²ΠΈΠ΅ Ρ ΡΠ°ΡΡΠ²ΠΎΡΠΈΡΠ΅Π»Π΅ΠΌ (ΡΠ°Π²Π΅Π»Π΅Π²Π°Ρ), Π° Π² Π½Π΅ΠΊΠΎΡΠΎΡΡΡ
ΡΠ»ΡΡΠ°ΡΡ
Π΅Π΄ΠΈΠ½ΡΡΠ²Π΅Π½Π½ΡΠΌΠΈ ΡΠ΅Π³ΠΈΡΡΡΠΈΡΡΠ΅ΠΌΡΠΌΠΈ ΠΊΠΎΠΌΠΏΠΎΠ½Π΅Π½ΡΠ°ΠΌΠΈ ΡΠ²Π»ΡΡΡΡΡ ΠΏΡΠΎΠ΄ΡΠΊΡΡ ΡΠ΅ΡΠΌΠΈΡΠ΅ΡΠΊΠΎΠΉ Π΄Π΅ΡΡΡΡΠΊΡΠΈΠΈ (Π»ΠΈΠΌΠΎΠ½Π½Π°Ρ). Π’Π°ΠΊ, ΠΏΡΠΈ Π°Π½Π°Π»ΠΈΠ·Π΅ ΡΠ°ΡΡΠ²ΠΎΡΠ° ΡΠ°Π²Π΅Π»Π΅Π²ΠΎΠΉ ΠΊΠΈΡΠ»ΠΎΡΡ Π² ΠΈΠ·ΠΎΠΏΡΠΎΠΏΠΈΠ»ΠΎΠ²ΠΎΠΌ ΡΠΏΠΈΡΡΠ΅ Π·Π°ΡΠΈΠΊΡΠΈΡΠΎΠ²Π°Π½ΠΎ ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½ΠΈΠ΅ Π΄Π²ΡΡ
ΡΠ»ΠΎΠΆΠ½ΡΡ
ΡΡΠΈΡΠΎΠ² - ΠΌΠΎΠ½ΠΎΠΈΠ·ΠΎΠΏΡΠΎΠΏΠΈΠ»- ΠΈ Π΄ΠΈΠΈΠ·ΠΎΠΏΡΠΎΠΏΠΈΠ»ΠΎΠΊΡΠ°Π»Π°ΡΠΎΠ².The literature data indicates that the results of gas chromatographic analysis of such low-volatile polar compounds as aliphatic dicarboxylic acids are characterized by high irreproducibility. Most of the previously published GC retention indices seem to be very spread out and appear to be erroneous. Similar irreproducibility is typical for some other physicochemical properties of these acids, namely melting temperatures, water solubility, etc. The experimental testing of the possibilities of gas chromatographic and/or GC-MS analysis of simplest dicarboxylic acids using standard non-polar polydimethylsiloxane stationary phases (BPX-1, RTX-5) has been fulfilled. It indicates that some compounds of this series (e.g., glutaric acid) are determined without decomposition, for others the interaction with solvent is typical (oxalic acid), and in some cases the single compounds observed are the products of thermal destruction (citric acid). Namely, the analysis of the solution of oxalic acid in isopropyl alcohol permits us to detect two esters - monoisopropyl and diisopropyl oxalates
Spectral Duality Between Heisenberg Chain and Gaudin Model
In our recent paper we described relationships between integrable systems
inspired by the AGT conjecture. On the gauge theory side an integrable spin
chain naturally emerges while on the conformal field theory side one obtains
some special reduced Gaudin model. Two types of integrable systems were shown
to be related by the spectral duality. In this paper we extend the spectral
duality to the case of higher spin chains. It is proved that the N-site GL(k)
Heisenberg chain is dual to the special reduced k+2-points gl(N) Gaudin model.
Moreover, we construct an explicit Poisson map between the models at the
classical level by performing the Dirac reduction procedure and applying the
AHH duality transformation.Comment: 36 page
Spectral Duality in Integrable Systems from AGT Conjecture
We describe relationships between integrable systems with N degrees of
freedom arising from the AGT conjecture. Namely, we prove the equivalence
(spectral duality) between the N-cite Heisenberg spin chain and a reduced gl(N)
Gaudin model both at classical and quantum level. The former one appears on the
gauge theory side of the AGT relation in the Nekrasov-Shatashvili (and further
the Seiberg-Witten) limit while the latter one is natural on the CFT side. At
the classical level, the duality transformation relates the Seiberg-Witten
differentials and spectral curves via a bispectral involution. The quantum
duality extends this to the equivalence of the corresponding Baxter-Schrodinger
equations (quantum spectral curves). This equivalence generalizes both the
spectral self-duality between the 2x2 and NxN representations of the Toda chain
and the famous AHH duality
Resonant Raman Scattering of ZnS, ZnO, and ZnS/ZnO Core/shell quantum dots
Resonant Raman scattering by optical phonon modes as well as their overtones was investigated in ZnS and ZnO quantum dots grown by the LangmuirβBlodgett technique. The in situ formation of ZnS/ZnO core/shell quantum dots was monitored by Raman spectroscopy during laser illumination
Deformed planar topological open string amplitudes on Seiberg-Witten curve
We study refined B-model via the beta ensemble of matrix models. Especially,
for four dimensional N=2 SU(2) supersymmetric gauge theories with N_f=0,1 and 2
fundamental flavors, we discuss the correspondence between deformed disk
amplitudes on each Seiberg-Witten curve and the Nekrasov-Shatashvili limit of
the corresponding irregular one point block of a degenerate operator via the
AGT correspondence. We also discuss the relation between deformed annulus
amplitudes and the irregular two point block of the degenerate operator, and
check a desired agreement for N_f=0 and 1 cases.Comment: 27 pages. v2: minor changes and references added. v3: minor
corrections and one reference adde
S-duality as a beta-deformed Fourier transform
An attempt is made to formulate Gaiotto's S-duality relations in an explicit
quantitative form. Formally the problem is that of evaluation of the Racah
coefficients for the Virasoro algebra, and we approach it with the help of the
matrix model representation of the AGT-related conformal blocks and Nekrasov
functions. In the Seiberg-Witten limit, this S-duality reduces to the Legendre
transformation. In the simplest case, its lifting to the level of Nekrasov
functions is just the Fourier transform, while corrections are related to the
beta-deformation. We calculate them with the help of the matrix model approach
and observe that they vanish for beta=1. Explicit evaluation of the same
corrections from the U_q(sl(2)) infinite-dimensional representation formulas
due to B.Ponsot and J.Teshner remains an open problem.Comment: 21 page
- β¦