This material is based upon work supported by the U.S. Department of Homeland Security under Grant Award Number 2010-ST-061-FD0001 through a grant awarded by the National Center for Food Protection and Defense at the University of Minnesota. Disclaimer: The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Department of Homeland Security or the National Center for Food Protection and Defense.

1. Gümüş Nanoparçacık Sentezi 15 <ol><li> 5 saniye boyunca 100 mi, aşırı saf su (18.2 ΩU) ve vorteks 18 mg gümüş nitrat çözeltisi ile çözülmüştür. </li><li> 5 saniye boyunca 1 ml su ve vorteks 27 mg sodyum sitrat dihidrat çözülür. </li><li> Bir karıştırma çubuğu ihtiva eden bir erlene hazırlanan gümüş nitrat çözeltisi her aktarın ve manyetik bir sıcak plaka üzerinde akıtma koydu. ~ 350 ° C de, 700 rpm&#39;lik bir karıştırma hızı ile kuvvetli karıştırma altında balon Isı (plaka sıcaklık ayarı). </li><li> kaynar zaman hemen erlene hazırlanan sodyum sitrat çözeltisi tüm ekleyin ve çözüm Ag NPS oluşumunu gösteren yeşilimsi kahverengi, açılana kadar ilave 25 dakika kaynatın çözüm bırakın. </li><li> Sıcak plaka şişeyi çıkarın ve sabit renk ve tran ile, başka bir manyetik plaka üzerine koydu (ısı değil) ve heyecan O / N oda sıcaklığında aynı karıştırma hızında karışım istikrarlı bir duruma ulaşana kadarsparency. Gerekirse hazırlanan Ag NPlerin emişi belirlemek üzere bir UV spektrometresi kullanarak. </li><li> 100 ml saf su ile nihai karışımı ile seyreltilir. </li><li> Gerekirse, üreticinin protokolüne uygun olarak Ag NPlerin boyutunu ölçmek için, bir Zetasizer kullanarak. </li><li> kapalı bir kaba Ag kolloid aktarın ve alüminyum folyo ile ışıktan korumak. Gerekirse kolloid 2 ay boyunca 4-7 ° C&#39;de buzdolabında saklanır. </li></ol> Bir SERS Aktif Filtre Membran 2. Fabrikasyon <ol><li> 50 mM NaCI solüsyonu yapmak üzere, 100 ml su içinde 2.92 g sodyum klorür (NaCI) içinde çözülür. </li><li> hazırlanan Ag NPlerin 1 ml 5 mM NaCI çözeltisi 1 ml ilave edilir ve 20 rpm&#39;de 10 dakika için bir sallanan karıştırıcıda karıştırın. Bu adım Ag nanoclustere içine Ag NPS bir araya etmektir. </li><li> Bir şırıngaya birleştirilebilen bir filtre tutucusu, bir membran filtre (PVDF, 0.1 um gözenek boyutu) yerleştirin. Daha küçük gözenek boyutu zar fo oldututarlı sinyalleri Ag nanoyığınlar yakalama ve üretiminde büyük gözenek boyutu membranı (yani, 0.22 mikron) daha und daha etkili. </li><li> Yük filtrasyon için şırınga içine hazırlanmış Ag nanoclustere 2 ml. şırınga filtre yuvasını takın ve elle 1 damla / sn akış hızında zarından Ag nanoclustere tüm hacmini geçmektedir. Membran tuzakları Ag nanokümeler, bir SERS-aktif filtre membran oluşturur. </li><li> Filtre tutucu filtre membran ayırın. zara hiçbir zarar sağlamak için bir cımbız kullanarak dış kenarında zarı tutarken özellikle dikkat gereklidir. Bir bardak slayt yaklaşık 3 dk ve yer zarının hava kuru. </li><li> SERS substratın Raman algılama <ol><li> 5 mW, 10X mikroskobik hedefi ayarlayın 2. 1 sn ve maruziyet numarasının pozlama süresi bir lazer gücüne sahip bir 780 nm dalga boyundaki lazer Raman cihazı ayarlayın. yazılım üzerinde objektif çok buna ayarlanmış olduğundan emin olun. &lt;/ Li&gt; <li> Raman aracın platform üzerine üstündeki membran ile cam slayt yerleştirin ve membran yüzeyinde odaklanmak için mikroskop kullanıyoruz. </li><li> Rasgele membran yüzeyinde 8-10 noktalar seçin ve enstrüman sırayla otomatik olarak toplayacaktır. analiz için üreticinin yazılımı açın spektral verileri. </li></ol></li></ol> SERS Aktif Filtre Sisteminin 3. Uygulama Kimyasal Bulaşanlar Algılama için <ol><li> 10 ppb ferbam çözeltisi hazırlayın. Dikkat: ferbam çok uçucudur. önlemler (maske ve gözlük) katı ağırlığında kullanın. <ol><li> 2 mg ferbam tozu tartılır ve bir stok çözeltisi (100 ppm) yapmak için 20 ml% 50 asetonitril (10 ml asetonitril ve 10 ml su) içinde çözülür. 30 saniye için şişeyi vorteksleyin. </li><li> Bir test tüpü içinde, 100 ppm ferbam çözeltisi 1 ml alın ve 10 ppm bir solüsyon hazırlamak için 9 ml% 50 asetonitril ekleyin. 5 saniye boyunca tüp vorteksleyin. </li><li> 1 ml alın10 ppm test tüpünde çözeltisi ve 9 ml% 50 asetonitril ilave 1 ppm bir solüsyon hazırlamak için. 5 saniye boyunca tüp vorteksleyin. </li><li> Bir test tüpü içinde 1 ppm çözeltisi 1 ml alın ve 100 ppb solüsyon yapmak için 9 ml% 50 asetonitril ekleyin. 5 saniye boyunca tüp vorteksleyin. </li><li> Bir test tüpü içinde, 100 ppb çözeltisi 1 ml alın ve 10 ppb solüsyon yapmak için 9 ml% 50 asetonitril ekleyin. 5 saniye boyunca tüp vorteksleyin. </li></ol></li><li> 1 ppm ampisilin çözeltisi hazırlayın. <ol><li> 10 mg ampisilin toz tartılır ve 100 ppm ampisilin solüsyon yapmak için, 100 ml su içinde çözülür. 30 saniye için şişeyi vorteksleyin. </li><li> Bir test tüpü içinde, 100 ppm çözeltisi 1 ml alın ve 10 ppm ampisilin çözeltisinin yapılması için 9 mL su ilave edilir. 5 saniye boyunca tüp vorteksleyin. </li><li> Bir test tüpü içinde 10 ppm çözeltisi 1 ml alın ve 1 ppm ampisilin çözeltisinin yapılması için 9 mL su ilave edilir. 5 saniye boyunca tüp vorteksleyin. </li></ol></li><li> yukarı bakacak şekilde NP kaplı tarafı, filtre yuvasına geri filtre membran koyun. &lt;/ Li&gt; <li> Yük 5 Yeni enjektöre bir örnek ml ve daha sonra içinde Ag kaplı membran ile filtre yuvasına takın. </li><li> El 1 damla / sn arasında bir akış hızında zar içinden numunenin tüm hacmi geçmektedir. Hedef moleküller, filtre zarı kaplanmış NP üzerine adsorbe edildi ve konsantre edilebilir. </li><li> yaklaşık 3 dakika boyunca filtre tutucu, hava kuru filtre zarı ayırmak ve adım 2.6 açıklandığı gibi aynı yöntemi kullanarak Raman aleti kullanılarak sinyalleri ölçmek. </li><li> 2.6 adımı tekrarlayın 2.2 başka Ag kaplı membran hazırlamak ve diğer numune tespiti için adım 3,3 takip etmek. </li></ol>

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P., He, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+surface-enhanced+Raman+scattering+detection+using+a+handheld+and+a+bench-top+Raman+spectrometer:+A+comparative+study.">Evaluation of surface-enhanced Raman scattering detection using a handheld and a bench-top Raman spectrometer: A comparative study.</a> Talanta. 129, 79-85 (2014).</li></ol>

The authors have nothing to disclose.

Bu protokol kritik adımlardan biri üniforma Ag NPS tutarlı sonuçlar için anahtar Ag NPS sentezi vardır. Isıtma süresi ve ön-maddeleri konsantrasyonları kesin olarak kontrol edilmelidir. Bu AGNPS hazırlanması ortalama büyüklüğü Zetasizer ile ölçülmüştür 80 nm, (veri gösterilmemiştir). Diğer önemli adım tuz konsantrasyonu ve toplama zamanı kesin olarak kontrol edilmelidir tuz toplanmasıdır. daha küçük bir gözenek boyutuna sahip membran tuzağı Ag nanoklastırlaar daha etkili bulunmuştur Buna ek olarak, membran seçimi de önemlidir. Bu çalışmada kullanılan özel membran için, ön yüz şırınga bağlamak için tutucu içerisine yerleştirilmesi gerekir, bir ön ve arka yan vardır. aşağı yerleştirilmişse, kaplama daha az etkili olmuştur. zarından geçerken kabarcıklar kaçınmak başarılı bir kaplamaya başka anahtarıdır. Bu testin sorun giderme için, adımları izleyerektavsiye edilmektedir. hiç veya çok az bir sinyal tespit edilirse, aşağıdaki nedenler için kontrol edin. ana nedeni Ag NPS filtre membran gözenekleri içinde sıkışıp için yeterli toplanmaz olabilir. tuz konsantrasyonu ve / veya kuluçka süresi artan toplama artırabilir. Aksi takdirde, filtre membran arka yukarı bakacak kontrol edin ve hacim veya numune konsantrasyonu membran yüklü olduğu çok düşük değil. Ag NPS boyut dağılımı çok geniş olabilir veya NPS eşit muhtemelen NP ya da çok hızlı çok fazla toplama için, membran üzerine dağıtılmış değildir: hedef molekülün sinyal tutarlı değilse, aşağıdaki nedenleri kontrol zarından geçen. , SERS substrat olarak 30-31 Ag dendritler kullanarak önceki verilerle karşılaştırıldığında bu filtre tabanlı SERS testinin duyarlılığı ferbam algılama çok daha yüksektir. Bu la akabilir filtre tabanlı sistemin avantajı, nedeniyleDaha fazla analit molekülleri SERS substrat üzerine konsantre edilir, böylece numunenin RGE miktarı. Resim santrifüj NP-analit kompleksinin toplanması için gerekli olduğu gibi, solüsyon bazlı yönteme göre filtre tabanlı sistemi kullanmanın bir diğer avantajı, işletme ve fieldable ölçüm kolaylığıdır. Bu yöntemin sınırlama karmaşık bileşenleri membran gözenekleri bloke edebilir gibi, örneğin doğrudan süt gibi karmaşık sıvı matrisler için kullanılamaz olduğunu. Tedavi öncesi membran geçirmeden önce müdahale bileşenleri kaldırmak için gereklidir. Özet olarak, sıvı gıda matris ve çevresel numuneler kontaminant veya yabancı madde katılmasını tespiti için kullanılabilecek olan, basit ve hassas bir filtre tabanlı SERS deneyi göstermektedir. ayrıca tespit sınırını zorlamaya, böyle NP boyutları ve miktarı, tuz konsantrasyonu, örnek hacmi ve enstrüman parametreleri gibi parametrelerin optimizasyonu gereklidir.

Yüzey Raman spektroskopisi (SERS) nanoteknoloji ile Raman spektroskopisi birleştiren bir tekniktir. Asil metalik nano-yüzeylerde analitlerin Raman saçılması yoğunluğu büyük ölçüde lokalize yüzey plazmon rezonansı ile geliştirilmiştir. 1 Gümüş nanopartiküller (Ag NPS) artık farkla en yaygın olarak kullanılan SERS nedeniyle yüksek geliştirme yeteneği yüzeylerde. 2 kadar olan Ag NPlerin çeşitli sentetik yöntemler geliştirilmiştir. 3-6 Ag NPS, sensitivite ve / veya işlevini geliştirmek için etkili bir SERS substratlar olarak tek başına ya da diğer malzemeler ve yapılar ile kombine edilebilir. 7-11 SERS teknikleri, gıda ve çevre örneklerinde çeşitli eser miktarda kirletici tespiti için büyük bir kapasiteye göstermiştir 12 Geleneksel olarak, bir SERS örneği hazırlamak için iki ortak yolu vardır:.. Çözüm tabanlı ve yüzey-temelli yöntemler 13 çözüm tabanlı yöntemiid örnekleri ile karıştırmak için NP kolloidler kullanır. Daha sonra NP-analit kompleksi santrifüj kullanılarak toplandı ve kurutulduktan sonra Raman ölçümü için bir katı destek üzerine tatbik edilir. Alt tabaka esas yöntem genellikle prefabrike bir katı alt-tabaka üzerine bir sıvı örneğinin birçok mikrolitre biriktirilmesi ile uygulanır. 14. Bununla birlikte, bu iki yöntem de, numune hacminin büyük bir miktarda etkin ve uygulanabilir. SERS testlerin bazı değişiklikler böyle bir filtre sistemi 15-21 entegrasyonu veya bir mikroakışkan cihazın dahil olarak hacim sınırları aştı. 21-24 modifiye SERS deneyleri, kimyasal kirleticiler izlemek için duyarlılık ve fizibilite büyük artışı göstermiştir büyük su örneklerinde. Burada pestisit ferbam ve antibiyotik ampisilin kalıntılarını tespit etmek için, imalat ve şırıngalı bir filtre göre SERS yönteminin uygulamanın ayrıntılı protokol göstermektedir.

<table border="0" cellpadding="0" cellspacing="0" width="604">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:211px;">Ampicillin</td>
			<td style="width:128px;">Fisher Scientific</td>
			<td style="width:136px;">BP1760-5</td>
			<td style="width:131px;">N/A</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:211px;">Ferbam</td>
			<td style="width:128px;">Chem Service</td>
			<td style="width:136px;">N-11970-250MG</td>
			<td style="width:131px;">98+%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:211px;">Silver nitrate</td>
			<td style="width:128px;">Sigma Aldrich</td>
			<td style="width:136px;">209139</td>
			<td style="width:131px;">99.0+%</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:211px;">Sodium citrate dehydrate</td>
			<td style="width:128px;">Sigma Aldrich</td>
			<td style="width:136px;">W302600</td>
			<td style="width:131px;">99+%</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:211px;">Sodium chloride</td>
			<td style="width:128px;">Sigma Aldrich</td>
			<td style="width:136px;">S7653</td>
			<td style="width:131px;">99.5+%</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:211px;">EMD Millipore Durapore PVDF Membrane Filters</td>
			<td style="width:128px;">Fisher Scientific</td>
			<td style="width:136px;">VVLP01300</td>
			<td style="width:131px;">0.10 &#181;m Pore Size, hydrophilic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:211px;">Polycarbonate Filter Holders</td>
			<td style="width:128px;">Cole-Parmer</td>
			<td style="width:136px;">EW-29550-40</td>
			<td style="width:131px;">13 mm diameter</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Analog Vortex Mixer</td>
			<td style="width:128px;">Fisher Scientific</td>
			<td>02-215-365</td>
			<td>N/A</td>
		</tr>
		<tr height="50">
			<td height="50" style="height:51px;width:211px;">Nutating Mixers</td>
			<td style="width:128px;">Fisher Scientific</td>
			<td>05-450-213</td>
			<td style="width:131px;">N/A</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:211px;">DXR Raman spectroscope</td>
			<td style="width:128px;">Thermo Scientific</td>
			<td style="width:136px;">IQLAADGABFFAHCMAPB</td>
			<td style="width:131px;">Laser power: 1 mW Exposure time: 5 s</td>
		</tr>
	</tbody>
</table>

a filter-based surface enhanced raman spectroscopic assay for rapid detection of chemical contaminants

We demonstrate a method to fabricate highly sensitive surface-enhanced Raman spectroscopic (SERS) substrates using a filter syringe system that can be applied to the detection of various chemical contaminants. Silver nanoparticles (Ag NPs) are synthesized via reduction of silver nitrate by sodium citrate. Then the NPs are aggregated by sodium chloride to form nanoclusters that could be trapped in the pores of the filter membrane. A syringe is connected to the filter holder, with a filter membrane inside. By loading the nanoclusters into the syringe and passing through the membrane, the liquid goes through the membrane but not the nanoclusters, forming a SERS-active membrane. When testing the analyte, the liquid sample is loaded into the syringe and flowed through the Ag NPs coated membrane. The analyte binds and concentrates on the Ag NPs coated membrane. Then the membrane is detached from the filter holder, air dried and measured by a Raman instrument. Here we present the study of the volume effect of Ag NPs and sample on the detection sensitivity as well as the detection of 10 ppb ferbam and 1 ppm ampicillin using the developed assay.

Bu deneyde önemli adımlar şematik diyagram (Şekil 1) gösterilmiştir. 2 maksimize hassasiyeti ulaşmak için membran kaplama olarak AGNPS optimize hacmini kullanmak için önemini göstermiştir Şekil. ferbam kullanıldığında 0.5 ml (yetersiz kaplama) ya da 2 ml (çok fazla kaplama) ile karşılaştırıldığında, Ag NPS 1 ml güçlü sinyali sağlar. Biz geliştirilen filtre tabanlı SERS deneyi ile büyük bir sinyal yoğunluğu ile 1 ppm (Şekil 1) 10 ppb seviyesinde ve ampisilin de ferbam tespit başardık. ferbam arasında SERS spektrumu 10 ppb tat karakteristik tepeler sergiler. 1386 cm tepe -1 karışık germe CN ve C = S titreşim ve simetrik CH 3 deformasyon değil. 1.516 cm-1 tepe CH3 veya CN ile germe ile ilişkilidir. 561 cm tepe <sup&gt; -1 SS gerilerek oluşturulur. 25-27 Ocak ppm ampisilin tayf, aynı zamanda açık bir şekilde tespit edilmiştir. 1594 cm -1 ve 1447 cm tepe -1 C = C sırasıyla germe ve CH 3 / CH 2 deformasyon vardır. 1001 cm güçlü tepe -1 benzen halkası titreşim olduğunu. 852 cm-1 tepe simetrik CNC germe ile ilişkilidir. 28-29 bir örnek analiz etmek için deney süresi önceden hazırlanmış Ag NPler SERS aktif Filtre membranının fabrikasyon dahil en az 20 dk. Şekil 4&#39;te gösterildiği gibi örnek hacmini arttırmak, biz ayrıca tespit limitini artırabilir. Numune hacmi artan Biz zirve yoğunlukta bir artış gözlendi. hacim ayarlanabilir ve algılama sınırı da ayarlanabilir olduğu gibi bu filtre tabanlı yöntemin avantajı olduğunu. ether.within-page = &quot;1&quot;&gt; <img alt="Şekil 1" src="/files/ftp_upload/53791/53791fig1.jpg" /> Şekil 1. Filtre SERS testinin şematik diyagramı. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53791/53791fig1large.jpg" target="_blank">Bu rakamın büyük halini görmek için lütfen buraya tıklayınız.</a> <img alt="şekil 2" src="/files/ftp_upload/53791/53791fig2.jpg" /> 5 mi, 100 ppb Şekil 2. SERS spektrumları Ag NPS farklı miktarda kaplanmış zarlardan geçen ferbam Yukarıdan aşağıya:. 1.0 mi NaCl ile 0.5 mi NaCl ile 0.5 mi Ag kolloid, 1.0 mi, Ag, 1.5, 1.5 mi, Ag ml NaCl, sırasıyla. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53791/53791fig2large.jpg" target="_blank">Bu rakamın büyük halini görmek için lütfen buraya tıklayınız.</a> 91 / 53791fig3.jpg &quot;/&gt; Ag NPS kaplı filtre zarı üzerinde ferbam ve ampisilin Şekil 3. SERS spektrumları Yukarıdan aşağıya:.% 50 asetonitril kontrolü, 10 ppb ferbam su kontrolü, 1 ppm Ampisilin, sırasıyla. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53791/53791fig3large.jpg" target="_blank">Büyük halini görmek için tıklayınız bu figür.</a> <img alt="Şekil 4," src="/files/ftp_upload/53791/53791fig4.jpg" /> Ag NPS kaplı filtre zarı üzerinde 100 ppb ferbam farklı hacimlerde Şekil 4. SERS spektrumları Yukarıdan aşağıya:. 3 ml ferbam, 5 ml ferbam, 7 ml ferbam, 9 ml ferbam, sırasıyla. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53791/53791fig4large.jpg" target="_blank">Büyük halini görmek için tıklayınız bu rakamın.</a>

Watch this Scientific Journal Video about A Filter-based Surface Enhanced Raman Spectroscopic Assay for Rapid Detection of Chemical Contaminants at JoVE.com

A Filter-based Surface Enhanced Raman Spectroscopic Assay for Rapid Detection of Chemical Contaminants

Imalat ve kimyasal kirleticilerin (örneğin, pestisid ferbam ve antibiyotik ampisilin) ​​tespiti için Raman spektroskopi (SERS) deneyi geliştirilmiş filtre tabanlı yüzey yapmak için bir prosedür sunulmuştur.

Kimyasal bulaşanların Hızlı Algılama için Raman Spektroskopisi Tahlili Geliştirilmiş A Filtre tabanlı Yüzey

We demonstrate a method to fabricate highly sensitive surface-enhanced Raman spectroscopic (SERS) substrates using a filter syringe system that can be ...

a-filter-based-surface-enhanced-raman-spectroscopic-assay-for-rapid

Nanyang Technological University

Research

JoVE Journal

Chemistry

9.3K Görüntüleme.  University of Massachusetts Amherst.  Imalat ve kimyasal kirleticilerin (örneğin, pestisid ferbam ve antibiyotik ampisilin) ​​tespiti için Raman spektroskopi (SERS) deneyi geliştirilmiş filtre tabanlı yüzey yapmak için bir prosedür sunulmuştur. 

Video: A Filter-based Surface Enhanced Raman Spectroscopic Assay for Rapid Detection of Chemical Contaminants

Preparation of Hydrophobic Metal-Organic Frameworks via Plasma Enhanced Chemical Vapor Deposition of Perfluoroalkanes for the Removal of Ammonia

Plasma enhanced chemical vapor deposition (PECVD) of perfluoroalkanes has long been studied for tuning the wetting properties of surfaces. For high surface area microporous materials, such as metal-organic frameworks (MOFs), unique challenges present themselves for PECVD treatments. Herein the protocol for development of a MOF that was previously unstable to humid conditions is presented. The protocol describes the synthesis of Cu-BTC (also known as HKUST-1), the treatment of Cu-BTC with PECVD of perfluoroalkanes, the aging of materials under humid conditions, and the subsequent ammonia microbreakthrough experiments on milligram quantities of microporous materials. Cu-BTC has an extremely high surface area (~1,800 m2/g) when compared to most materials or surfaces that have been previously treated by PECVD methods. Parameters such as chamber pressure and treatment time are extremely important to ensure the perfluoroalkane plasma penetrates to and reacts with the inner MOF surfaces. Furthermore, the protocol for ammonia microbreakthrough experiments set forth here can be utilized for a variety of test gases and microporous materials.

Herein the procedures for plasma enhanced chemical vapor deposition of perfluoroalkanes on microporous materials such as metal-organic frameworks to enhance their stability and hydrophobicity are described. Furthermore, breakthrough testing of milligram quantities of samples is described in detail.

Plazma ile Hidrofobik Metal-Organik Altyapıları hazırlanması Amonyak Kaldırma için perfluorobütanlar Kimyasal Buhar Kaplama Geliştirilmiş

Plasma enhanced chemical vapor deposition (PECVD) of perfluoroalkanes has long been studied for tuning the wetting properties of surfaces. For high ...

Kimya

A Simple and Rapid Protocol for Measuring Neutral Lipids in Algal Cells Using Fluorescence

Algae are considered excellent candidates for renewable fuel sources due to their natural lipid storage capabilities. Robust monitoring of algal fermentation processes and screening for new oil-rich strains requires a fast and reliable protocol for determination of intracellular lipid content. Current practices rely largely on gravimetric methods to determine oil content, techniques developed decades ago that are time consuming and require large sample volumes. In this paper, Nile Red, a fluorescent dye that has been used to identify the presence of lipid bodies in numerous types of organisms, is incorporated into a simple, fast, and reliable protocol for measuring the neutral lipid content of Auxenochlorella protothecoides, a green alga. The method uses ethanol, a relatively mild solvent, to permeabilize the cell membrane before staining and a 96 well micro-plate to increase sample capacity during fluorescence intensity measurements. It has been designed with the specific application of monitoring bioprocess performance. Previously dried samples or live samples from a growing culture can be used in the assay.

A simple protocol to determine the neutral lipid content of algal cells using a Nile Red staining procedure is described. This time-saving technique offers an alternative to traditional gravimetric-based lipid quantification protocols. It has been designed for the specific application of monitoring bioprocess performance.

Floresan kullanma Alg hücrelerinde nötral Lipidler Ölçüm Basit ve Hızlı Protokolü

Algae are considered excellent candidates for renewable fuel sources due to their natural lipid storage capabilities. Robust monitoring of algal ...

Preparation of Highly Porous Coordination Polymer Coatings on Macroporous Polymer Monoliths for Enhanced Enrichment of Phosphopeptides

We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous polymer monoliths. The developed approach is based on the preparation of a macroporous polymer containing carboxylic acid functional groups and the subsequent step-by-step solution-based controlled growth of a layer of a porous coordination polymer on the surface of the pores of the polymer monolith. The prepared metal-organic polymer hybrid has a high specific micropore surface area. The amount of iron(III) sites is enhanced through metal-organic coordination on the surface of the pores of the functional polymer support. The increase of metal sites is related to the number of iterations of the coating process.
The developed preparation scheme is easily adapted to a capillary column format. The functional porous polymer is prepared as a self-contained single-block porous monolith within the capillary, yielding a flow-through separation device with excellent flow permeability and modest back-pressure. The metal-organic polymer hybrid column showed excellent performance for the enrichment of phosphopeptides from digested proteins and their subsequent detection using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The presented experimental protocol is highly versatile, and can be easily implemented to different organic polymer supports and coatings with a plethora of porous coordination polymers and metal-organic frameworks for multiple purification and/or separation applications.

A procedure for the preparation of porous hybrid separation media composed of a macroporous polymer monolith internally coated by a high surface area microporous coordination polymer is presented.

Phosphopeptides Gelişmiş Zenginleştirme için Makrogözenekli Polimer Monoliths üzerinde yüksek Gözenekli Koordinasyon Polymer Coatings Hazırlanması

We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous ...

A Method to Manipulate Surface Tension of a Liquid Metal via Surface Oxidation and Reduction

Controlling interfacial tension is an effective method for manipulating the shape, position, and flow of fluids at sub-millimeter length scales, where interfacial tension is a dominant force. A variety of methods exist for controlling the interfacial tension of aqueous and organic liquids on this scale; however, these techniques have limited utility for liquid metals due to their large interfacial tension.
Liquid metals can form soft, stretchable, and shape-reconfigurable components in electronic and electromagnetic devices. Although it is possible to manipulate these fluids via mechanical methods (e.g., pumping), electrical methods are easier to miniaturize, control, and implement. However, most electrical techniques have their own constraints: electrowetting-on-dielectric requires large (kV) potentials for modest actuation, electrocapillarity can affect relatively small changes in the interfacial tension, and continuous electrowetting is limited to plugs of the liquid metal in capillaries.
Here, we present a method for actuating gallium and gallium-based liquid metal alloys via an electrochemical surface reaction. Controlling the electrochemical potential on the surface of the liquid metal in electrolyte rapidly and reversibly changes the interfacial tension by over two orders of magnitude ( &#820;500 mN/m to near zero). Furthermore, this method requires only a very modest potential (&#60; 1 V) applied relative to a counter electrode. The resulting change in tension is due primarily to the electrochemical deposition of a surface oxide layer, which acts as a surfactant; removal of the oxide increases the interfacial tension, and vice versa. This technique can be applied in a wide variety of electrolytes and is independent of the substrate on which it rests.

We present a method to control the interfacial energy of a liquid metal in an electrolyte via electrochemical deposition (or removal) of a surface oxide layer. This simple method can control the capillary behavior of gallium-based liquid metals by tuning the interfacial energy rapidly, significantly, and reversibly using modest voltages.

Bir Yöntem Yüzey Oksidasyon ve İndirgeme yoluyla Sıvı Metal Yüzey Gerilim işleyin

Controlling interfacial tension is an effective method for manipulating the shape, position, and flow of fluids at sub-millimeter length scales, where ...

Preparation of Biopolymer Aerogels Using Green Solvents

Although the first reports on aerogels made by Kistler1 in the 1930s dealt with aerogels from both inorganic oxides (silica and others) and biopolymers (gelatin, agar, cellulose), only recently have biomasses been recognized as an abundant source of chemically diverse macromolecules for functional aerogel materials. Biopolymer aerogels (pectin, alginate, chitosan, cellulose, etc.) exhibit both specific inheritable functions of starting biopolymers and distinctive features of aerogels (80-99% porosity and specific surface up to 800 m2/g). This synergy of properties makes biopolymer aerogels promising candidates for a wide gamut of applications such as thermal insulation, tissue engineering and regenerative medicine, drug delivery systems, functional foods, catalysts, adsorbents and sensors. This work demonstrates the use of pressurized carbon dioxide (5 MPa) for the ionic cross linking of amidated pectin into hydrogels. Initially a biopolymer/salt dispersion is prepared in water. Under pressurized CO2 conditions, the pH of the biopolymer solution is lowered to 3 which releases the crosslinking cations from the salt to bind with the biopolymer yielding hydrogels. Solvent exchange to ethanol and further supercritical CO2 drying (10 - 12 MPa) yield aerogels. Obtained aerogels are ultra-porous with low density (as low as 0.02 g/cm3), high specific surface area (350 - 500 m2/g) and pore volume (3 - 7 cm3/g for pore sizes less than 150 nm).

A new way for the production of biopolymer-based aerogels by carbon dioxide (CO2) induced gelation is shown. The technique utilizes pressurized carbon dioxide (5 MPa) for the production of biopolymer hydrogels and supercritical CO2 (12 MPa) to convert gels into aerogels. The only solvents needed besides CO2 are water and ethanol.

Yeşil Solventler kullanma Biyopolimer Aerogels Hazırlanması

Although the first reports on aerogels made by Kistler1 in the 1930s dealt with aerogels from both inorganic oxides (silica and others) and biopolymers ...

A Novel Technique for Raman Analysis of Highly Radioactive Samples Using Any Standard Micro-Raman Spectrometer

A novel approach for the Raman measurement of nuclear materials is reported in this paper. It consists of the enclosure of the radioactive sample in a tight capsule that isolates the material from the atmosphere. The capsule can optionally be filled with a chosen gas pressurized up to 20 bars. The micro-Raman measurement is performed through an optical-grade quartz window. This technique permits accurate Raman measurements with no need for the spectrometer to be enclosed in an alpha-tight containment. It therefore allows the use of all options of the Raman spectrometer, like multi-wavelength laser excitation, different polarizations, and single or triple spectrometer modes. Some examples of measurements are shown and discussed. First, some spectral features of a highly radioactive americium oxide sample (AmO2) are presented. Then, we report the Raman spectra of neptunium oxide (NpO2) samples, the interpretation of which is greatly improved by employing three different excitation wavelengths, 17O doping, and a triple mode configuration to measure the anti-stokes Raman lines. This last feature also allows the estimation of the sample surface temperature. Finally, data that were measured on a sample from Chernobyl lava, where phases are identified by Raman mapping, are shown.

We present a technique for Raman spectroscopic analysis of highly radioactive samples compatible with any standard micro-Raman spectrometer, without any radioactive contamination of the instrument. We also show some applications using actinide compounds and irradiated fuel materials.

Herhangi bir standart mikro-Raman spektrometresi ile yüksek radyoaktif Örneklerin Raman Analizi için yeni bir teknik

A novel approach for the Raman measurement of nuclear materials is reported in this paper. It consists of the enclosure of the radioactive sample in a ...

Observation and Analysis of Blinking Surface-enhanced Raman Scattering

From a single molecule at a silver nanoaggregate junction, blinking surface-enhanced Raman scattering (SERS) is observed. Here, a protocol is presented on how to prepare the SERS-active silver nanoaggregate, record a video of certain blinking spots in the microscopic image, and analyze the blinking statistics. In this analysis, a power law reproduces the probability distributions for bright events relative to their duration. The probability distributions for dark events are fitted by a power law with an exponential function. The parameters of the power law represent molecular behavior in both bright and dark states. The random walk model and the speed of the molecule across the entire silver surface can be estimated. It is difficult to estimate even when using averages, autocorrelation functions, and super-resolution SERS imaging. In the future, power law analyses should be combined with spectral imaging, because the origins of blinking cannot be confirmed by this analysis method alone.

This protocol describes the analysis of blinking surface-enhanced Raman scattering due to the random walk of a single molecule on a silver surface using power laws.

Gözlem ve yüzey gelişmiş Raman saçılması yanıp sönen analizi

From a single molecule at a silver nanoaggregate junction, blinking surface-enhanced Raman scattering (SERS) is observed. Here, a protocol is presented on ...

Color Spot Test As a Presumptive Tool for the Rapid Detection of Synthetic Cathinones

Synthetic cathinones are a large class of new psychoactive substances (NPS) that are increasingly prevalent in drug seizures made by law enforcement and other border protection agencies globally. Color testing is a presumptive identification technique indicating the presence or absence of a particular drug class using rapid and uncomplicated chemical methods. Owing to their relatively recent emergence, a color test for the specific identification of synthetic cathinones is not currently available. In this study, we introduce a protocol for the presumptive identification of synthetic cathinones, employing three aqueous reagent solutions: copper(II) nitrate, 2,9-dimethyl-1,10-phenanthroline (neocuproine) and sodium acetate. Small pin-head sized amounts (approximately 0.1-0.2 mg) of the suspected drugs are added to the wells of a porcelain spot plate, and each reagent is then added dropwise sequentially before heating on a hotplate. A color change from very light blue to yellow-orange after 10 min indicates the likely presence of synthetic cathinones. The highly stable and specific test reagent has the potential for use in the presumptive screening of unknown samples for synthetic cathinones in a forensic laboratory. However, the nuisance of an added heating step for the color change result limits the test to laboratory application and decreases the likelihood of an easy translation to field testing.

Here we present a simple, inexpensive, and selective chemical spot test protocol for the detection of synthetic cathinones, a class of new psychoactive substances. The protocol is suitable for use in various areas of law enforcement that encounter illicit material.

Renk sentetik Cathinones hızlı tespiti için meşru bir araç olarak nokta testi

Synthetic cathinones are a large class of new psychoactive substances (NPS) that are increasingly prevalent in drug seizures made by law enforcement and ...

Gold Nanoparticle Modified Carbon Fiber Microelectrodes for Enhanced Neurochemical Detection

For over 30 years, carbon-fiber microelectrodes (CFMEs) have been the standard for neurotransmitter detection. Generally, carbon fibers are aspirated into glass capillaries, pulled to a fine taper, and then sealed using an epoxy to create electrode materials that are used for fast scan cyclic voltammetry testing. The use of bare CFMEs has several limitations, though. First and foremost, the carbon fiber contains mostly basal plane carbon, which has a relatively low surface area and yields lower sensitivities than other nanomaterials. Furthermore, the graphitic carbon is limited by its temporal resolution, and its relatively low conductivity. Lastly, neurochemicals and macromolecules have been known to foul at the surface of carbon electrodes where they form non-conductive polymers that block further neurotransmitter adsorption. For this study, we modify CFMEs with gold nanoparticles to enhance neurochemical testing with fast scan cyclic voltammetry. Au3+ was electrodeposited or dipcoated from a colloidal solution onto the surface of CFMEs. Since gold is a stable and relatively inert metal, it is an ideal electrode material for analytical measurements of neurochemicals. Gold nanoparticle modified (AuNP-CFMEs) had a stability to dopamine response for over 4 h. Moreover, AuNP-CFMEs exhibit an increased sensitivity (higher peak oxidative current of the cyclic voltammograms) and faster electron transfer kinetics (lower &#916;EP or peak separation) than bare unmodified CFMEs. The development of AuNP-CFMEs provides the creation of novel electrochemical sensors for detecting fast changes in dopamine concentration and other neurochemicals at lower limits of detection. This work has vast applications for the enhancement of neurochemical measurements. The generation of gold nanoparticle modified CFMEs will be vitally important for the development of novel electrode sensors to detect neurotransmitters in vivo in rodent and other models to study neurochemical effects of drug abuse, depression, stroke, ischemia, and other behavioral and disease states.

In this study, we modify carbon-fiber microelectrodes with gold nanoparticles to enhance the sensitivity of neurotransmitter detection.

Gelişmiş nörokimyasal algılama için altın Nanopmakale modifiye karbon fiber Mikroelektrotlar

For over 30 years, carbon-fiber microelectrodes (CFMEs) have been the standard for neurotransmitter detection. Generally, carbon fibers are aspirated into ...

A Two-Step Pyrolysis-Gas Chromatography Method with Mass Spectrometric Detection for Identification of Tattoo Ink Ingredients and Counterfeit Products

Tattoo inks are complex mixtures of ingredients. Each of them possesses different chemical properties which have to be addressed upon chemical analysis. In this method for two-step pyrolysis online coupled to gas chromatography mass spectrometry (py-GC-MS) volatile compounds are analyzed during a first desorption run. In the second run, the same dried sample is pyrolyzed for analysis of non-volatile compounds such as pigments and polymers. These can be identified by their specific decomposition patterns. Additionally, this method can be used to differentiate original from counterfeit inks. Easy screening methods for data evaluation using the average mass spectra and self-made pyrolysis libraries are applied to speed up substance identification. Using specialized evaluation software for pyrolysis GS-MS data, a fast and reliable comparison of the full chromatogram can be achieved. Since GC-MS is used as separation technique, the method is limited to volatile substances upon desorption and after pyrolysis of the sample. The method can be applied for quick substance screening in market control surveys since it requires no sample preparation steps.

This method for two-step pyrolysis online coupled to gas chromatography with mass spectrometric detection and data evaluation protocol can be used for multi-component analysis of tattoo inks and discrimination of counterfeit products.

Dövme mürekkebi maddeleri ve taklit ürünlerin tanımlanması için kütle spektrometrik tespiti ile Iki adımlı Pyrolysis-Gas Kromatografi yöntemi

Tattoo inks are complex mixtures of ingredients. Each of them possesses different chemical properties which have to be addressed upon chemical analysis. ...