A new electrochemical method for determination of imidacloprid using chronopotentiometry on thin film mercury and glassy carbon electrode was presented. The most important experimental parameters of chronopotentiometry were examined and optimized with respect to imidacloprid analytical signal. Imidacloprid provided well-defined reduction peak in Britton-Robinson buffer on thin film mercury electrode at &#x2212;1.0&#x2009;V (versus Ag/AgCl (KCl, 3.5&#x2009;mol/L)) and on glassy carbon electrode at &#x2212;1.2&#x2009;V (versus Ag/AgCl (KCl, 3.5&#x2009;mol/L)). The reduction time was linearly proportional to concentrations from 0.8 to 30.0&#x2009;mg/L on thin film mercury electrode and from 7.0 to 70.0&#x2009;mg/L on glassy carbon electrode. The detection limits were 0.17&#x2009;mg/L and 0.93&#x2009;mg/L for thin film mercury and glassy carbon electrode, respectively. The estimation of method precision as a function of repeatability and reproducibility showed relative standard deviations values lower than 3.73&#x25;. Recovery values from 97.3 to 98.1&#x25; confirmed the accuracy of the proposed method, while the constancy of the transition time with deliberated small changes in the experimental parameters indicated a very good robustness. A minor influence of possible interfering compounds proved good selectivity of the method. Developed method was applied for imidacloprid determination in commercial pesticide formulations and river water samples.

Ana &#x110;urovi&#x107;

Zorica Stojanovi&#x107;

Sne&#x17e;ana Kravi&#x107;

Nada Grahovac

Vojislava Bursi&#x107;

Gorica Vukovi&#x107;

Zvonimir Suturovi&#x107;

Development and Validation of Chronopotentiometric Method for Imidacloprid Determination in Pesticide Formulations and River Water Samples

We investigated the possibility of utilizing both oleaginous yeast species accumulating large amounts of lipids (<i>Yarrowia lipolytica, Rhodotorula glutinis, Trichosporon cutaneum, </i>and<i> Candida </i>sp.) and traditional biotechnological nonoleaginous ones (<i>Kluyveromyces polysporus, Torulaspora delbrueckii, </i>and<i> Saccharomyces cerevisiae</i>) as potential producers of dietetically important major fatty acids. The main objective was to examine the cultivation conditions that would induce a high ratio of dietary fatty acids and biomass. Though genus-dependent, the type of nitrogen source had a higher influence on biomass yield than the C/N ratio. The nitrogen source leading to the highest lipid accumulation was potassium nitrate, followed by ammonium sulfate, which is an ideal nitrogen source supporting, in both oleaginous and nonoleaginous species, sufficient biomass growth with concomitantly increased lipid accumulation. All yeast strains displayed high (70&#x2013;90&#x25;) content of unsaturated fatty acids in total cell lipids. The content of dietary fatty acids of interest, namely, palmitoleic acid and linoleic acid, reached in<i> Kluyveromyces </i>and<i> Trichosporon </i>strains over 50&#x25; of total fatty acids and the highest yield, over 280&#x2009;mg per g of dry cell weight of these fatty acids, was observed in<i> Trichosporon </i>with ammonium sulfate as nitrogen source at C/N ratio 70.

Irena Kolouchov&#xe1;

Olga Ma&#x165;&#xe1;tkov&#xe1;

Karel Sigler

Jan Mas&#xe1;k

Tom&#xe1;&#x161; &#x158;ezanka

Production of Palmitoleic and Linoleic Acid in Oleaginous and Nonoleaginous Yeast Biomass

Plant hormones are the key regulators of adaptive stress response. Abiotic stresses such as drought and salt are known to affect the growth and productivity of plants. It is well known that the levels of plant hormones such as zeatin (ZA), abscisic acid (ABA), salicylic acid (SA), jasmonic acid (JA), and brassinolide (BR) fluctuate upon abiotic stress exposure. At present, there is not any single suitable liquid chromatography-mass spectrometry (LC-MS) method for simultaneous analysis of BR and other plant hormones involved in abiotic stresses. In the present study, we developed a simple, sensitive, and rapid method for simultaneous analysis of five major plant hormones, ZA, ABA, JA, SA, and BR, which are directly or indirectly involved in drought and salt stresses. The optimized extraction procedure was simple and easy to use for simultaneous measurement of these plant hormones in<i> Arabidopsis thaliana</i>. The developed method is highly reproducible and can be adapted for simultaneous measurement of changes in plant hormones (ZA, ABA, JA, SA, and BR) in response to abiotic stresses in plants like<i> A. thaliana</i> and tomato.

Deepak M. Kasote

Ritesh Ghosh

Jun Young Chung

Jonggeun Kim

Inhwan Bae

Hanhong Bae

Multiple Reaction Monitoring Mode Based Liquid Chromatography-Mass Spectrometry Method for Simultaneous Quantification of Brassinolide and Other Plant Hormones Involved in Abiotic Stresses

Box-Behnken design was applied to optimize high performance liquid chromatography (HPLC) conditions for the simultaneous determination of potassium sorbate, sodium benzoate, carmoisine, allura red, ponceau 4R, and caffeine in commercial soft drinks. The experimental variables chosen were pH (6.0–7.0), flow rate (1.0–1.4 mL/min), and mobile phase ratio (85–95% acetate buffer). Resolution values of all peak pairs were used as a response. Stationary phase was Inertsil OctaDecylSilane- (ODS-) 3V reverse phase column (250 × 4.6 mm, 5 <i>μ</i>m) dimensions. The detection was performed at 230 nm. Optimal values were found 6.0 pH, 1.0 mL/min flow rate, and 95% mobile phase ratio for the method which was validated by calculating the linearity (<svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.6370001pt" id="M1" height="12.2284pt" version="1.1" viewBox="-0.0498162 -11.5914 59.768 12.2284" width="59.768pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><path id="g113-115" d="M393 379C402 394 400 411 393 422C384 437 365 448 348 448C301 448 237 372 186 285H182L193 335C210 408 205 448 178 448C150 448 80 402 29 344L45 321C80 355 114 373 122 373C128 373 130 365 124 330C106 228 76 98 50 -5L57 -12C82 -5 112 3 132 6L172 203C196 256 234 304 254 329C275 355 293 367 306 367C318 367 330 360 342 348C347 343 355 343 365 350S386 367 393 379Z"/></g><g transform="matrix(.0091,0,0,-0.0091,5.488,-5.741)"><path id="g50-51" d="M414 144C384 79 371 75 317 75H135L276 221C367 316 408 376 408 465C408 570 327 635 237 635C179 635 131 609 100 575L42 494L67 471C94 510 138 565 205 565C277 565 321 517 321 435C321 348 258 270 195 195C146 137 88 81 33 26V0H411C423 44 433 88 446 135L414 144Z"/></g><g transform="matrix(.013,0,0,-0.013,14.066,0)"><path id="g117-92" d="M512 230V281L75 514V456L453 256V254L75 55V-3L512 230Z"/></g><g transform="matrix(.013,0,0,-0.013,25.329,0)"><path id="g113-49" d="M241 635C89 635 35 457 35 312C35 153 89 -12 240 -12C390 -12 443 166 443 312C443 466 390 635 241 635ZM238 602C329 602 354 454 354 312C354 172 330 22 240 22C152 22 124 173 124 313S148 602 238 602Z"/></g><g transform="matrix(.013,0,0,-0.013,31.569,0)"><path id="g113-47" d="M113 -12C146 -12 170 11 170 46C170 78 146 103 114 103S58 78 58 46C58 11 82 -12 113 -12Z"/></g><g transform="matrix(.013,0,0,-0.013,34.533,0)"><path id="g113-58" d="M244 635C114 635 38 519 38 422C38 317 111 240 217 240C236 240 255 244 277 256L345 292C311 140 203 39 59 15L64 -15C89 -15 150 -5 204 17C339 72 440 202 440 386C440 521 368 635 244 635ZM228 602C326 602 352 479 352 390C352 370 351 347 348 324C327 308 293 296 258 296C174 296 124 369 124 458C124 517 152 602 228 602Z"/></g><g transform="matrix(.013,0,0,-0.013,40.775,0)"><use xlink:href="#g113-58"/></g><g transform="matrix(.013,0,0,-0.013,47.016,0)"><path id="g113-55" d="M137 343C167 482 260 545 321 574C357 591 397 603 429 609L423 641C382 634 335 622 295 608C189 570 37 457 37 238C37 84 125 -12 242 -12C362 -12 447 89 447 209C447 311 374 393 267 393C247 393 226 386 204 376L137 343ZM227 337C318 337 361 256 361 173C361 105 336 22 258 22C176 22 126 120 126 240C126 266 127 291 132 310C155 323 189 337 227 337Z"/></g><g transform="matrix(.013,0,0,-0.013,53.256,0)"><path id="g113-51" d="M412 140C382 77 369 73 315 73H129L270 222C362 320 402 379 402 466C402 571 322 635 234 635C177 635 130 609 99 576L42 495L64 475C90 514 133 568 201 568C274 568 318 519 318 435C318 349 255 267 193 193C144 135 87 78 32 23V0H405C417 45 427 89 440 131L412 140Z"/></g></svg>), accuracy (recoveries ≥ 95.75%), precision (intraday variation ≤ 1.923%, interday variation ≤ 1.950%), limits of detection (LODs), and limits of quantification (LOQs) parameters. LODs and LOQs for analytes were in the range of 0.10–0.19 <i>μ</i>g/mL and 0.33–0.63 <i>μ</i>g/mL, respectively. The proposed method was applied successfully for the simultaneous determination of the mixtures of five food additives and caffeine in soft drinks.

B&#xfc;rge A&#x15f;&#xe7;&#x131;

&#x15e;ule Din&#xe7; Zor

&#xd6;zlem Aksu D&#xf6;nmez

Development and Validation of HPLC Method for the Simultaneous Determination of Five Food Additives and Caffeine in Soft Drinks

This method employs liquid chromatography-tandem mass spectrometry to rapidly quantify chitin-derived glucosamine for estimating fungal biomass. Analyte retention was achieved using hydrophilic interaction liquid chromatography, with a zwitter-ionic stationary phase (ZIC-HILIC), and isocratic elution using 60% 5 mM ammonium formate buffer (pH 3.0) and 40% ACN. Inclusion of muramic acid and its chromatographic separation from glucosamine enabled calculation of the bacterial contribution to the latter. Galactosamine, an isobaric isomer to glucosamine, found in significant amounts in soil samples, was also investigated. The two isomers form the same precursor and product ions and could not be chromatographically separated using this rapid method. Instead, glucosamine and galactosamine were distinguished mathematically, using the linear relationships describing the differences in product ion intensities for the two analytes. The<i> m/z</i> transitions of 180 <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.04980993pt" id="M1" height="6.27169pt" version="1.1" viewBox="-0.0498162 -6.22188 16.9064 6.27169" width="16.9064pt"><g transform="matrix(.013,0,0,-0.013,2.179,0)"><path id="g117-148" d="M901 255C861 290 790 361 716 442L694 427L796 280H69V230H796L694 83L716 68C790 149 861 220 901 255Z"/></g></svg> 72 and 180 <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.04980993pt" id="M2" height="6.27169pt" version="1.1" viewBox="-0.0498162 -6.22188 16.9064 6.27169" width="16.9064pt"><g transform="matrix(.013,0,0,-0.013,2.179,0)"><use xlink:href="#g117-148"/></g></svg> 84 were applied for the detection of glucosamine and galactosamine and that of 252 <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.04980993pt" id="M3" height="6.27169pt" version="1.1" viewBox="-0.0498162 -6.22188 16.9064 6.27169" width="16.9064pt"><g transform="matrix(.013,0,0,-0.013,2.179,0)"><use xlink:href="#g117-148"/></g></svg> 126 for muramic acid. Limits of detection were in the nanomolar range for all included analytes. The total analysis time was 6 min, providing a high sample throughput method.

Madelen A. Olofsson

Dan Bylund

Liquid Chromatography with Electrospray Ionization and Tandem Mass Spectrometry Applied in the Quantitative Analysis of Chitin-Derived Glucosamine for a Rapid Estimation of Fungal Biomass in Soil

Enantiomeric separation of citalopram (CIT) was developed using a reversed phase HPLC (RP-HPLC) with sulfobutylether-<i>β</i>-cyclodextrin (SBE-<i>β</i>-CD) as a chiral mobile phase additive. The effects of the pH value of aqueous buffer, concentration of chiral additive, composition of mobile phase, and column temperature on the enantioseparation of CIT were investigated on the Hedera ODS-2 C<sub>18</sub> column (250 mm × 4.6 mm × 5.0 um). A satisfactory resolution was achieved at 25°C using a mobile phase consisting of a mixture of aqueous buffer (pH of 2.5, 5 mM sodium dihydrogen phosphate, and 12 mM SBE-<i>β</i>-CD), methanol, and acetonitrile with a volumetric ratio of 21 : 3 : 1 and flow rate of 1.0 mL/min. This analytical method was evaluated by examining the precision (lower than 3.0%), linearity (regression coefficients close to 1), limit of detection (0.070 <i>µ</i>g/mL for (<svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.2064009pt" id="M1" height="8.8423pt" version="1.1" viewBox="-0.0498162 -8.6359 8.28119 8.8423" width="8.28119pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><path id="g113-83" d="M610 18C585 26 567 34 540 68C517 97 499 128 476 171C452 215 425 276 413 304C496 332 570 394 570 494C570 555 545 595 509 619S419 650 364 650H139L133 622C216 615 219 612 203 527L129 132C112 40 105 36 23 28L17 0H279L285 28C199 34 194 40 211 132L239 284H284C320 284 334 275 351 236C374 182 394 140 420 93C459 23 495 -1 592 -8H600L610 18ZM480 485C480 424 449 372 403 342C374 323 338 316 293 316H245L291 562C296 589 301 601 311 608S337 618 358 618C432 618 480 575 480 485Z"/></g></svg>)-CIT and 0.076 <i>µ</i>g/mL for (<svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.2064009pt" id="M2" height="8.8423pt" version="1.1" viewBox="-0.0498162 -8.6359 6.25863 8.8423" width="6.25863pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><path id="g113-84" d="M449 634C442 637 425 643 405 650C376 660 341 666 307 666C181 666 98 590 98 485C98 400 170 343 215 310L246 288C307 243 343 204 343 147C343 67 291 18 219 18C104 18 61 124 51 202L23 199C28 124 27 71 27 47C47 22 122 -16 204 -16C324 -16 428 60 428 174C428 256 379 309 307 360L276 382C223 419 179 455 179 516C179 576 221 632 293 632C379 632 410 564 418 487L448 490C446 536 446 592 449 634Z"/></g></svg>)-CIT), and limit of quantitation (0.235 <i>µ</i>g/mL for (<svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.2064009pt" id="M3" height="8.8423pt" version="1.1" viewBox="-0.0498162 -8.6359 8.28119 8.8423" width="8.28119pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-83"/></g></svg>)-CIT and 0.254 <i>µ</i>g/mL for (<svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.2064009pt" id="M4" height="8.8423pt" version="1.1" viewBox="-0.0498162 -8.6359 6.25863 8.8423" width="6.25863pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-84"/></g></svg>)-CIT).

Yangfeng Peng

Quan Sophia He

Jiang Cai

Enantioseparation of Citalopram by RP-HPLC, Using Sulfobutyl Ether-<i>β</i>-Cyclodextrin as a Chiral Mobile Phase Additive

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<p><em>International Journal of Analytical Chemistry</em> publishes research reporting new experimental results and chemical methods, especially in relation to important analytes, difficult matrices, and topical samples.</p>


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<p>Chief Editor, Professor Charles L. Wilkins, is a Distinguished Professor of Chemistry and Biochemistry at the University of Arkansas, USA. His research focuses on the development of novel analytical chemistry instrumentation and analysis paradigms.</p>


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International Journal of Analytical Chemistry | Hindawi

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International Journal of Analytical Chemistry publishes research reporting new experimental results and chemical methods, especially in relation to important analytes, difficult matrices, and topical samples.

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International Journal of Analytical Chemistry

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International Journal of Analytical Chemistry