Name: preparation of dmmtav and dmdtav using dmav for environmental applications: synthesis, purification, and confirmation
Uploaded: 2018-03-09T13:00:00.000+00:00
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Description: Watch this Scientific Journal Video about Preparation of DMMTAV and DMDTAV Using DMAV for Environmental Applications: Synthesis, Purification, and Confirmation at JoVE.com

Bu araştırma temel bilim araştırma programı tarafından desteklenmiştir (proje sayısı: 2016R1A2B4013467) aracılığıyla Ulusal Araştırma Vakfı, Kore (Bilim Bakanlığı, ICT ve gelecek planlama 2016 tarafından finanse edilen ve ayrıca Kore temel bilim tarafından desteklenen NMK) Enstitüsü araştırma programı (proje sayısı: C36707).

1. DMMTAV sentezi
<ol><li>
Kimyasal hazırlama ve molar oranı karıştırma DMAV, Na2S ve H2SO4 Not: DMAV: Na2S:H2kadar4 1:1.6:1.6 =<ol>
<li>DMAV 40 mL deiyonize ve N25,24 g çözülür-tasfiye (en az 30 dk için tasfiye) 50 mL santrifüj tüpü suya.</li>
		<li>Na2S reaktif 14,41 g Na2S·9H2O 50 ml deiyonize, N2çözülerek hazırlamak-bir 250 mL şişe su tasfiye.</li>
		<li>Hazırlamak için 40 mL konsantre sülfirik asit (% 96) 3,3 mL ekleyerek4 reaktif deiyonize Yani H2ve N2-50 mL santrifüj tüpü suya temizlendi. Not: DMAVson molar oranı: Na2S:H2SO4 = 1:1.6:1.6 1,3,4,8,15.</li>
		<li>DMAV çözüm (Adım 1.1.1) hazırlanan 40 mL 50 mL 250 mL şişe (Adım 1.1.2) bulunan Na2S çözeltisi ekleyin. DMAV 10 mL tasfiye su ile içeren tüp durulayın ve bu 250 mL şişe de ekleyin.</li>
		<li>Şişeye cam tüpleri ile donatılmış bir üç delikli lastik tıpa ile kapatın. Camı kullan N2 gaz giriş, çıkış ve H2SO4 çözüm giriş, sırasıyla tüpler. Hemen şişeye kapattıktan sonra balonun içine N2 gaz akışını sağlar. Not: Gaz basıncı sıçramasına olmadan tepki çözüm yüzey üzerinde akmaya sağlanmalıdır.</li>
		<li>Aside dayanıklı H2cam tüp SO4 çözüm giriş H2hazır 40 mL kadar eklemek için 50 mL şırınga ile boru bağlanmak4 çözüm (Adım 1.1.3). H240 mL kadar ekleyin4 çözüm, yavaş yavaş ve kademeli bir şekilde. Uyarı: Sülfürik asit ekleyerek üzerine beyaz duman-ecek var olmak oluşturmak; iyi havalandırılmış duman başlığı kullan.</li>
		<li>Monitör renk değişikliği sülfürik asit düzenli aralıklarla ekleme süre şişeye tepki karışımı. Bir ara ile 4-5 mL damla H2/ çok korumak4; karışım beyaz bir bulutlu çözüm olmalıdır. Not: Anlık sarı yağış konsantre sülfürik asit hızlı ek nedeniyle görünebilir.</li>
		<li>Reaksiyon çözüm adım 1.1.4 başlangıcından bu yana 1 h için ayakta olun.</li>
	</ol>
</li>
	<li>
DMMTAV çıkarma sıvı-sıvı ekstraksiyon yöntemiyle
	<ol>
<li>1 saat sonra yaklaşık 200 mL Dietil eter içeren bir HCI'yi huni tepki solüsyonu dökün.</li>
		<li>5-10 dk, gaz stopcock geçerek birkaç kez serbest bırakmak için huni sallamak. Not: Sentezlenmiş DMMTAV Dietil eter (0.713 g·mL-1) üst katmana aktarılır. Uyarı: Dietil eter gaz zararlı olabilir; iyi havalandırılmış duman başlığı kullan.</li>
		<li>Bir ölçek tepki çözüm toplamak ve ayrı ayrı DMMTAV bir şişe içeren Dietil eter toplamak. Reaksiyon çözüm aynı HCI'yi hunide geri yerleştirin ve yaklaşık 200 mL taze Dietil eter reshaking için ekleyin. Adımları 1.2.2 - 1.2.3 üç kere tekrar edin.</li>
		<li>Tekrar toplanan Dietil eter adım 1.2.3 aynı HCI'yi huni içine dökün ve yaklaşık 100 mL N2ekleyin-deiyonize suyla temizlendi. Sallamak için 5-10 dk ve N2atın-deiyonize su ve bir kaç mL Dietil eter saflık amaçlar için temizlendi. Cam petri kabına (en az 160 mm iç çapı) ve minimum yüksekliği 50 mm içinde kalan Dietil eter toplamak.</li>
		<li>Cam petri kabına bir N2 atmosfer tür dönüştürme önlemek için torpido aktarın. Uyarı: Çözücü vakum pompa ile çıkış pass kutusunun içine çekti değil emin olun.</li>
		<li>Dimethylmonothioarsinate beyaz bir çökelti kadar kuru (crystalized DMMTAV) cam petri kabına üzerinde oluşturulur. Not: Protokol burada duraklatılmış.</li>
	</ol>
</li>
	<li>
Doğrulama sentezlenmiş DMMTAV ve depolama
	<ol>
<li>Crystalized DMMTAV, beyaz çökelti al ve ölçmek ve toplam ağırlığı kaydetmek. Uyarı: Hidrojen sülfür gazı zehirlenmesinden önlemek için iyi havalandırılan duman hood veya torpido kullanın.</li>
		<li>Erime crystalized DMMTAV N250 ml-deiyonize suyla temizlendi ve sarı çökelti 0.2 µm şırınga filtre ile filtre.</li>
		<li>DMAV itibariyle toplam DMMTAV, Yani≈9, 649 mg As· dönüştürülür varsayıyorum L-1. DMMTAV ≈1 mg· hisse senedi çözüm sulandırmak L-1 ve ≈40 µg· L-1 Electrospray iyonlaşma kullanarak doğrulama analizi için kitle Spectromtery (ESI-MS) ve HPLC-ICP-MS, anılan sıraya göre.</li>
		<li>M/z DMMTAV m/z 155 pozitif iyon modunda veya m/z 153 (Tablo 1) negatif iyon modunda ESI-MS11,16 ve parçaları kullanarak analiz. Not: Bkz: başvuru değerleri m/z (Tablo 1).</li>
		<li>DMMTAV HPLC-ICP-MS11,16,17 uygun eluent koşullar ile kullanarak hisse senedi çözümde Kromatografik analiz etmek ve büyük bir tepe'de açıklanan tutma zaman bulundu onaylayın Edebiyat. Not: Sentezlenmiş DMMTAV saflığı adım 1.3.5 analiz sonuçlarından kullanılarak hesaplanması.</li>
		<li>ICP-MS asit sindirim11 ' den sonra kullanarak toplam arsenik konsantrasyonu analiz ve doğru DMMTAV konsantrasyon sentezlenmiş DMMTAV hisse senedi çözüm seyreltme faktörler ve saflık, olduğu gibi aşağıdaki eşitliği kullanarak hesaplar: Analiz toplam konsantrasyonu (µg· olarak L-1) · Seyreltme faktörü · Saflık (%) doğru DMMTAV konsantrasyon DMMTAV hisse senedi çözüm (µg· = L-1)</li>
		<li>Daha fazla nicel Türleşme analiz18için karanlıkta DMMTAV hisse senedi çözüm 4 ° C'de depolayın.</li>
	</ol>
</li>
</ol>2. DMDTAV sentezi
<ol><li>
Kimyasal hazırlama ve molar oranı karıştırma DMAV , Na2S ve H2SO4 Not: DMAV: Na2S:H2kadar4 1:7.5:7.5 =<ol>
<li>DMAV 40 mL deiyonize su 50 mL santrifüj tüpü içinde 1,38 gr geçiyoruz.</li>
		<li>Na2S reaktif 18.01 g Na2S·9H2O bir 250 mL şişe 50 mL deiyonize suda çözülerek hazırlayın.</li>
		<li>4 mL konsantre sülfirik asit (% 96) 40 mL deiyonize su ekleyerek4 reaktif bir 50 mL santrifüj tüpü bulunan H2hazırlamak. Not: DMAVson molar oranı: Na2S:H2SO4 = 1:7.5:7.51,3,4,8,15.</li>
		<li>DMAV çözüm (Adım 2.1.1) hazırlanan 40 mL 50 mL 250 mL şişe (Adım 2.1.2) bulunan Na2S çözeltisi ekleyin. DMAV 10 mL deiyonize su ile içeren tüp durulayın ve bu 250 mL şişe de ekleyin.</li>
		<li>H2hazır 40 mL kadar ekleyin4 çözüm (2.1.3. adım) yavaş yavaş ve kademeli bir şekilde, balonun içine.</li>
		<li>Sülfürik asit düzenli aralıklarla ekleme süre şişeye tepki karışımı renk değişikliği izlemek. Bir ara ile 4-5 mL damla H2/ çok korumak4; karışımı bir beyaz/sarı bulutlu çözüm olmalıdır. Not: Anlık sarı yağış nedeniyle hızlı bir ek konsantre sülfirik asit görünebilir. Uyarı: Sülfürik asit ekleyerek üzerine beyaz duman-ecek var olmak oluşturmak; iyi havalandırılan duman başlığı kullan.</li>
		<li>Flask örtü olmadan gecede tepki çözümde korumak. Not: Protokol burada duraklatılmış.</li>
	</ol>
</li>
	<li>
Katı faz ayıklama (SPE) yöntemini kullanarak DMDTAV çıkarma
	<ol>
<li>Sonra gece ayakta tepki, C18 kullanarak tepki solüsyonu yazın silis tabanlı SPE tuzağa düşürmek için filtre DMDTAV reçine üzerinde sentezledim. Uyarı: İyi havalandırılmış duman başlığı kullan.</li>
		<li>10 mM amonyum asetat (pH 6.3) 0,77 g amonyum asetat deiyonize su 1 litre içinde çözülerek hazırlayın. 10 mM amonyum asetat yeterli hacmi adsorbed DMDTAVayıklamak için C18 şırınga (Adım 2.2.1) elute. Bir cam Petri kabına (en az 160 mm iç çapı) ve minimum yüksekliği 50 mm filtre uygulanmış amonyum asetat toplamak.</li>
		<li>Cam petri kabına bir N2 atmosfer tür dönüştürme önlemek için torpido aktarın. Uyarı: Solvent vakum pompa ile çıkış pass kutusunun içine çekti değil emin olun.</li>
		<li>Dimethyldithioarsinate beyaz bir çökelti kadar kuru (crystalized DMDTAV) cam petri çanak üzerinde kurdu. Not: Protokol burada duraklatılmış.</li>
	</ol>
</li>
	<li>
Doğrulama sentezlenmiş DMDTAV ve depolama
	<ol>
<li>Crystalized DMDTAVbeyaz çökelti al ve ölçüm kayıt toplam ağırlığını ölçmek. Uyarı: Bir iyi havalandırılmış duman hood veya torpido hidrojen sülfür gazı zehirlenmesinden engellemek için kullanın.</li>
		<li>Erime crystalized DMDTAV N250 ml-50 mL tasfiye deiyonize suyla santrifüj kapasitesi tüp ve herhangi bir çökelti 0.2 µm şırınga filtre ile filtre.</li>
		<li>DMAV itibarıyla Toplam DMDTAV, Yani≈2, 539 mg As· dönüştürülür varsayıyorum L-1. DMDTAV ≈1 mg· hisse senedi çözüm sulandırmak L-1 ve ≈40 µg· L-1 ESI-MS ve HPLC-ICP-MS, sırasıyla kullanarak doğrulama analizi için.</li>
		<li>M/z DMDTAV m/z 171 pozitif iyon modunda veya m/z 169 (Tablo 1) negatif iyon modunda ESI-MS11,16 ve parçaları kullanarak analiz. Not: Bkz: başvuru değerleri m/z (Tablo 1).</li>
		<li>DMDTAV HPLC-ICP-MS11,16,17 uygun eluent koşullar ile kullanarak hisse senedi çözümde Kromatografik analiz etmek ve açıklanan tutma zamanı bir tepe bulunabilir doğrulayın Edebiyat. Not: Sentezlenmiş DMDTAV saflığı adım 2.3.5 analiz sonuçlarından kullanılarak hesaplanması.</li>
		<li>ICP-MS asit sindirim11 ' den sonra kullanarak toplam arsenik konsantrasyonu analiz ve doğru DMDTAV konsantrasyon sentezlenmiş DMDTAV hisse senedi çözüm seyreltme faktörler ve saflık aşağıdaki eşitliği kullanarak hesaplar: Analiz toplam konsantrasyonu (µg· olarak L-1) · Seyreltme faktörü · Saflık (%) DMDTA hisse senedi çözüm (µg·V konsantrasyon gerçek DMDTAV = L-1)</li>
		<li>Daha fazla nicel Türleşme analiz18için karanlıkta DMDTAV hisse senedi çözüm 4 ° C'de depolayın.</li>
	</ol>
</li>
</ol>

<ol>
	<li>Suzuki, K. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dimethylthioarsenicals+as+arsenic+metabolites+and+their+chemical+preparation.">Dimethylthioarsenicals as arsenic metabolites and their chemical preparation.</a> Chem. Res. Toxicol. 17, 914-921 (2004).</li><li>Kuroda, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microbial+metabolite+of+dimethylarsinic+acid+is+highly+toxic+and+genotoxic.">Microbial metabolite of dimethylarsinic acid is highly toxic and genotoxic.</a> Toxicol. Appl. Pharmacol. 198, 345-353 (2004).</li><li>Naranmandura, H., Iwata, K., Suzuki, K. T., Ogra, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distribution+and+metabolism+of+four+different+dimethylated+arsenicals+in+hamsters.">Distribution and metabolism of four different dimethylated arsenicals in hamsters.</a> Toxicol. Appl. Pharmacol. 245, 67-75 (2010).</li><li>Naranmandura, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+toxicity+of+arsenic+metabolites+in+human+bladder+cancer+EJ-1+cells.">Comparative toxicity of arsenic metabolites in human bladder cancer EJ-1 cells.</a> Chem. Res. Toxicol. 24, 1586-1596 (2011).</li><li>Wallschlager, D., London, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+methylated+arsenic-sulfur+compounds+in+groundwater.">Determination of methylated arsenic-sulfur compounds in groundwater.</a> Environ. Sci. Technol. 42, 228-234 (2008).</li><li>Zhang, J., Kim, H., Townsend, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methodology+for+assessing+thioarsenic+formation+potential+in+sulfidic+landfill+environments.">Methodology for assessing thioarsenic formation potential in sulfidic landfill environments.</a> Chemosphere. 107, 311-318 (2014).</li><li>Shimoda, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proposal+for+novel+metabolic+pathway+of+highly+toxic+dimethylated+arsenics+accompanied+by+enzymatic+sulfuration,+desulfuration+and+oxidation.">Proposal for novel metabolic pathway of highly toxic dimethylated arsenics accompanied by enzymatic sulfuration, desulfuration and oxidation.</a> Trace Elem. Med. Biol. 30, 129-136 (2015).</li><li>Naranmandura, H., Suzuki, T. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Formation+of+dimethylthioarsenicals+in+red+blood+cells.">Formation of dimethylthioarsenicals in red blood cells.</a> Toxicol. Appl. Pharmacol. 227, 390-399 (2008).</li><li>Leffers, L., Ebert, F., Taleshi, S. M., Francesconi, A. K., Schwerdtle, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+toxicological+characterization+of+two+arsenosugars+and+their+metabolites.">In vitro toxicological characterization of two arsenosugars and their metabolites.</a> Mol. Nutr. Food Res. 57, 1270-1282 (2013).</li><li>Wang, Q. Q., Thomas, J. D., Naranmandura, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Important+of+being+thiomethylated:+Formation,+Fate+and+Effects+of+methylated+thioarsenicals.">Important of being thiomethylated: Formation, Fate and Effects of methylated thioarsenicals.</a> Chem. Res. Toxicol. 25, 281-289 (2015).</li><li>Kim, Y. T., Lee, H., Yoon, H. O., Woo, N. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinetics+of+dimethylated+thioarsenicals+and+the+formation+of+highly+toxic+dimethylmonothioarsinic+acid+in+environment.">Kinetics of dimethylated thioarsenicals and the formation of highly toxic dimethylmonothioarsinic acid in environment.</a> Environ. Sci. Technol. 50, 11637-11645 (2016).</li><li>Cullen, W. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methylated+and+thiolated+arsenic+species+for+environmental+and+health+research+-+A+review+on+synthesis+and+characterization.">Methylated and thiolated arsenic species for environmental and health research - A review on synthesis and characterization.</a> J. Environ. Sci. 49, 7-27 (2016).</li><li>Fricke, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chromatographic+separation+and+identification+of+products+form+the+reaction+of+dimethylarsinic+acid+with+hydrogen+sulfide.">Chromatographic separation and identification of products form the reaction of dimethylarsinic acid with hydrogen sulfide.</a> Chem. Res. Toxicol. 18, 1821-1829 (2005).</li><li>Fricke, M., Zeller, M., Cullen, W., Witkowski, M., Creed, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dimethylthioarsinic+anhydride:+a+standard+for+arsenic+speciation.">Dimethylthioarsinic anhydride: a standard for arsenic speciation.</a> Anal. Chim. Acta. 583, 78-83 (2007).</li><li>Suzuki, K. T., Iwata, K., Naranmandura, H., Suzuki, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metabolic+differences+between+twon+dimethylthioarsenicals+in+rats.">Metabolic differences between twon dimethylthioarsenicals in rats.</a> Toxicol. Appl. Pharmacol. 218, 166-173 (2007).</li><li>Jeong, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+simultaneous+analytical+method+to+determine+arsenic+speciation+using+HPLC-ICP-MS:+Arsenate,+arsenite,+monomethylarsonic+acid,+dimethylarsinic+acid,+dimethyldithioarsinic+acid,+and+dimethylmonothioarsinic+acid.">Development of a simultaneous analytical method to determine arsenic speciation using HPLC-ICP-MS: Arsenate, arsenite, monomethylarsonic acid, dimethylarsinic acid, dimethyldithioarsinic acid, and dimethylmonothioarsinic acid.</a> Microchem. J. 134, 295-300 (2017).</li><li>Li, Y., Low, C. -. K., Scott, A. J., Amal, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Arsenic+speciation+in+municipal+landfill+leachate.">Arsenic speciation in municipal landfill leachate.</a> Chemosphere. 79, 794-801 (2010).</li><li>Conklin, D. S., Fricke, W. M., Creed, A. P., Creed, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigation+of+the+pH+effects+on+the+formation+of+methylated+thio-arsenicals,+and+the+effects+of+pH+and+temperature+on+their+stability.">Investigation of the pH effects on the formation of methylated thio-arsenicals, and the effects of pH and temperature on their stability.</a> J. Anal. At. Spectrom. 23, 711-716 (2008).</li><li>Hansen, H. R., Raab, A., Jaspara, M., Milne, F. B., Feldmann, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sulfur-containing+arsenical+mistaken+for+dimethylarsinous+acid+[DMA(III)]+and+identified+as+a+natural+metabolite+in+urine:+major+implications+for+studies+on+arsenic+metabolism+and+toxicity.">Sulfur-containing arsenical mistaken for dimethylarsinous acid [DMA(III)] and identified as a natural metabolite in urine: major implications for studies on arsenic metabolism and toxicity.</a> Chem. Res. Toxicol. 17, 1086-1091 (2004).</li><li>Mandal, B. K., Suzuki, K. T., Anzai, K., Yamaguchi, K., Sei, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+SEC-HPLC-ICP-MS+hyphenated+technique+for+identification+of+sulfur-containing+arsenic+metabolites+in+biological+samples.">A SEC-HPLC-ICP-MS hyphenated technique for identification of sulfur-containing arsenic metabolites in biological samples.</a> J. Chromatogr. B. 874, 64-76 (2008).</li><li>Bartel, M., Ebert, F., Leffers, L., Karst, U., Schwerdtle, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toxicological+characterization+of+the+inorganic+and+organic+arsenic+metabolite+thio-DMAV+in+cultured+human+lung+cells.">Toxicological characterization of the inorganic and organic arsenic metabolite thio-DMAV in cultured human lung cells.</a> J. Toxicol. 2011, (2011).</li><li>An, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Formation+of+dimethyldithioarsinic+acid+in+a+simulated+landfill+leachate+in+relation+to+hydrosulfide+concentration.">Formation of dimethyldithioarsinic acid in a simulated landfill leachate in relation to hydrosulfide concentration.</a> Environ. Geochem. Health. 38, 255-263 (2016).</li><li>Chen, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Arsenic+speciation+in+the+blood+of+arsenite-treated+F344+rats.">Arsenic speciation in the blood of arsenite-treated F344 rats.</a> Chem. Res. Toxicol. 26, 952-962 (2013).</li><li>Alava, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=HPLC-ICP-MS+method+development+to+monitor+arsenic+speciation+changes+by+human+gut+microbiota.">HPLC-ICP-MS method development to monitor arsenic speciation changes by human gut microbiota.</a> Biomed. Chromatogr. 26, 524-533 (2012).</li><li>Kurosawa, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+metabolic+activation+associated+with+glutathione+in+dimethylmonoarsinic+acid+(DMMTAV)-induced+toxicity+obtained+from+in+vitro+reaction+of+DMMTAV+with+glutathione.">A novel metabolic activation associated with glutathione in dimethylmonoarsinic acid (DMMTAV)-induced toxicity obtained from in vitro reaction of DMMTAV with glutathione.</a> J. trace Elem. Med. Biol. 33, 87-94 (2016).</li></ol>

Yazarlar ifşa gerek yok.

Gelişmiş iletişim kuralı önceki çalışmalar1,3,4,8,15 atlanmış veya kısaltılmış, hangi zorluklarla veya başarısızlık sırasında yol açmış olabilir önemli adımlar açıklık vardır DMMTAV ve DMDTAV sentezi. DMMTAV oksidasyon duyarlı1,5olduğu iç...

Dimethylarsinic asit (DMAV) Akut toksisite ve metilasyonu ve thiolation yenmesi1,2üzerine geçiren nedeniyle genotoxicity sergilemek için kanıtlanmıştır beri arsenik thiolation metabolik yolu vardır yoğun olmuştur vitro ve in vivo3,4 de olduğu gibi çevre medya (Örneğin, çöp sızıntı)5,6okudu. Önceki yıllarda yapılan çalışmalarda her ikisi de azaltılmış ve thiolated analogları DMAV yaşayan hücreleri, örnek, dimethylarsinous asit (DMAIII), dimethylmonothioarsinic asit (DMMTAV) ve dimethyldithioarsinic asit (için bulduk DMDTAV)7,8,9, dimethylated thioarsenicals DMMTAV diğer inorganik veya organik arsenicals10bilinen daha büyük toksisite sergilenmesi gibi. Son derece sulfidic koşulları11altında çevre ve insanlar için bir risk oluşturabilecek bu yana yüksek derecede toksik thioarsenicals bolluk ciddi çevresel etkileri vardır. Ancak, DMMTAV ve DMDTAV (trans) oluşumu ve onların kaderi çevre medya mekanizmaları hala daha fazla çalışma gerektirir. Böylece, thioarsenicals kantitatif analiz DMMTAV ve DMDTAVçevresel etkileri anlayış geliştirmek için gereklidir.
Standart kimyasallar kantitatif analiz için anahtar gereksinimi olmakla birlikte, DMMTAV ve DMDTAV standartları sayesinde diğer türler türler dönüşmesi riski yüksek önceki çalışmalarda kopyalayan tarafından elde etmek zordur ve unstandardized sentez yordamlar12. Ayrıca, başvurulan yöntemleri standart kimyasallar sentezleme ve kantitatif analiz performans, pratik sorunlara neden olabilir bazı kısıtlamalara sahiptir. DMMTAV ve DMDTAV sık DMAV, Na2S ve H24 ' te bir belirli molar oranı1 veya köpüren H2S gaz Yani DMAV 13,14bir çözüm ile karıştırılarak hazırlanır. Oksijen kullanarak doğrudan temini, son derece zehirli ve zor bir deneyimsiz kullanıcı için denetime H2S gazı kükürt tarafından kabarcıklanma yöntemi özellikleri değiştirme. Tersine, thiolation, DMMTAV ve DMDTAV çevre sudies5,6,12, kalitatif analiz için yaygın olarak kullanılan yukarıdaki karıştırma yöntem1, özellikleri DMAV H2Na2S ve H24 ve üretir DMMTAV ve DMDTAVolarak hedef kimyasallar, üretmek daha kolay stokiometrik kontrol sağlayan, doğrudan karşılaştırıldığında bu yüzden karıştırarak oluşturulan S H2S gaz kullanın.
Yöntemi yordamları1,3,4,8,15 karıştırma başvuru bu çalışma sergi kısıtlamalar bazı yol açabilir kritik onların deneysel adımlar bahsedilen deneysel hatası. Örneğin, belirli solvent (deiyonizeYani, su) hazırlık ve ayıklama ayrıntılarını ve sentezlenmiş arsenicals kristalleşme aşırı kısaltılmış veya yeterince ayrıntılı bir biçimde anlatılan değil. Böyle dağınık ve yordam adımları hakkında sınırlı bilgi thioarsenicals ve güvenilmez miktar analiz tutarsız oluşumuna neden olabilir. Bu nedenle, burada geliştirilen değiştirilmiş protokolünü DMMTAV ve DMDTAV hisse senedi çözümleri sayısal türler ayırma analizi ile sentezi açıklar.

<table><tbody><tr><td>Cacodylic acid</td><td>Sigma-Aldrich</td><td>20835-10G-F</td><td></td></tr><tr><td>Sodium sulfide nonahydrate</td><td>Sigma-Aldrich</td><td>S2006-500G</td><td></td></tr><tr><td>Sulfuric acid 96%</td><td>J.T.Baker</td><td>0000011478</td><td></td></tr><tr><td>Ammonium acetate</td><td>Sigma-Aldrich</td><td>A7262-500G</td><td></td></tr><tr><td>Formic acid 98%</td><td>Wako Pure Chemical Industries, Ltd.</td><td>066-00461</td><td></td></tr><tr><td>Diethyl ether (Extra Pure)</td><td>Junsei Chemical</td><td>33475-0380</td><td></td></tr><tr><td>Adapter cap for 60 mL Bond Elut catridges</td><td>Agilent Technologies</td><td>12131004</td><td>Syringe type of SPE</td></tr><tr><td>Bond Elut C18 cartridge</td><td>Agilent Technologies</td><td>14256031</td><td>Syringe type of SPE</td></tr><tr><td>HyPURITY C-18</td><td>Thermo Scientific</td><td>22105-254630</td><td>5 um, 125 x 4.6 mm</td></tr><tr><td>Glovebox</td><td>Chungae-chun, Rep. of Korea</td><td></td><td>Customized&amp;nbsp;</td></tr><tr><td>Agilent 1260 Infinity Bio-inert LC</td><td>Agilent Technologies</td><td>DEAB600252, DEACH00245</td><td></td></tr><tr><td>Agilent Technologies 7700 Series ICP-MS</td><td>Agilent Technologies</td><td>JP12031510</td><td></td></tr><tr><td>Finnigan LCQ Deca XP MAX Mass Spectrometer System</td><td>Thermo Electron Corporation</td><td>LDM10627</td><td></td></tr></tbody></table>

preparation of dmmtav and dmdtav using dmav for environmental applications: synthesis, purification, and confirmation

Dimethylmonothioarsinic asit (DMMTAV) gibi Dimethylated thioarsenicals ve dimethyldithioarsinic asit (DMDTAV), dimethylarsinic asit (DMAV) thiolation metabolik yolu tarafından üretilen, son zamanlarda olmuştur çevre yanı sıra insan organlarını buldum. DMMTAV ve DMDTAV dimethylated thioarsenicals ve çevre medya onların istikrar ekolojik etkileri belirlemek için sayısal. Bu bileşiklerin sentezi yöntemi önceki çalışmalarda zorlu çoğaltılıyor yapma unstandardized özeldir. Ayrıca, tür dönüşümü olmadan bileşiklerin depolama da dahil olmak üzere depolama teknikleri hakkında bilgi eksikliği vardır. Ayrıca, sadece sınırlı bilgi sentez yöntemleri hakkında kullanılabildiğinden, standart kimyasallar sentezleme ve kantitatif analiz gerçekleştirme deneysel zorluklar olabilir. Burada sunulan protokolü için dimethylated thioarsenicals, DMMTAV ve DMDTAV, pratik olarak değiştirilmiş sentez yöntemi sağlar ve tür ayırma analizi yüksek performanslı sıvı miktar içinde yardımcı olacaktır Kromatografi İndüktif eşleşmiş plazma kütle spektrometresi (HPLC-ICP-MS) ile birlikte. Bu yordamın deneysel adımını kimyasal reaktifler, filtrasyon yöntemleri ve depolama hazırlanması üzerinde odaklanarak tarafından modifiye edilmiştir.

DMMTAV yanlışlıkla DMAIII sentez yöntemi19tarafından hazırlanmış olup, doğrulama sentezlenmiş DMMTAV ve DMDTAV sentezi ve çıkarma ve ideal standart belirleme için önemli bir adım olduğu için kimyasal maddeler. Sentezlenmiş kimyasallar DMMTA en yüksekV (MW 154 g·mol-1) ve DMDTAV (MW 170 g·mol-1) kitle ücret oranı (m/z) electrospray iyonlaşma kütl...

Watch this Scientific Journal Video about Preparation of DMMTAV and DMDTAV Using DMAV for Environmental Applications: Synthesis, Purification, and Confirmation at JoVE.com

Preparation of DMMTAV and DMDTAV Using DMAV for Environmental Applications: Synthesis, Purification, and Confirmation

DMMTAV ve çevresel uygulamaları için DMAV kullanarak DMDTAV hazırlanması: sentez, arıtma ve onay

Bu yazı için dimethylmonothioarsinic asit (DMMTAV) değiştirilmiş deneysel protokoller sunar ve dimethyldithioarsinic asit (DMDTAV) sentezi, dimethylarsinic asit (DMAV) thiolation DMAV karıştırma yoluyla inducing , Na2S ve H2kadar4. Değiştirilen protokol böylece deneysel hataları kantitatif analiz sebep olabilecek sentez adımları sınırlamaları aşmak deneysel bir kılavuz sağlar.

Dimethylated thioarsenicals such as dimethylmonothioarsinic acid (DMMTAV) and dimethyldithioarsinic acid (DMDTAV), which are produced by the metabolic ...

preparation-dmmtav-dmdtav-using-dmav-for-environmental-applications

Research

JoVE Journal

Environment

Preparation of DMMTAV and DMDTAV Using DMAV for Environmental Applications: Synthesis, Purification, and Confirmation

5.5K Görüntüleme.  Korea Basic Science Institute, Seoul Center. Bu yazı için dimethylmonothioarsinic asit (DMMTAV) değiştirilmiş deneysel protokoller sunar ve dimethyldithioarsinic asit (DMDTAV) sentezi, dimethylarsinic asit (DMAV) thiolation DMAV karıştırma yoluyla inducing , Na2S ve H2kadar4. Değiştirilen protokol böylece deneysel hataları kantitatif analiz sebep olabilecek sentez adımları sınırlamaları aşmak deneysel bir kılavuz sağlar....

Video: Preparation of DMMTAV and DMDTAV Using DMAV for Environmental Applications: Synthesis, Purification, and Confirmation

Controlling the Size, Shape and Stability of Supramolecular Polymers in Water

For aqueous based supramolecular polymers, the simultaneous control over shape, size and stability is very difficult1. At the same time, the ability to do so is highly important in view of a number of applications in functional soft matter including electronics, biomedical engineering, and sensors. In the past, successful strategies to control the size and shape of supramolecular polymers typically focused on the use of templates2,3, end cappers4 or selective solvent techniques5. 
Here we disclose a strategy based on self-assembling discotic amphiphiles that leads to the control over stack length and shape of ordered, chiral columnar aggregates. By balancing electrostatic repulsive interactions on the hydrophilic rim and attractive non-covalent forces within the hydrophobic core of the polymerizing building block, we manage to create small and discrete spherical objects6,7. Increasing the salt concentration to screen the charges induces a sphere-to-rod transition. Intriguingly, this transition is expressed in an increase of cooperativity in the temperature-dependent self-assembly mechanism, and more stable aggregates are obtained. 
For our study we select a benzene-1,3,5-tricarboxamide (BTA) core connected to a hydrophilic metal chelate via a hydrophobic, fluorinated L-phenylalanine based spacer (Scheme 1). The metal chelate selected is a Gd(III)-DTPA complex that contains two overall remaining charges per complex and necessarily two counter ions. The one-dimensional growth of the aggregate is directed by &pi;-&pi; stacking and intermolecular hydrogen bonding. However, the electrostatic, repulsive forces that arise from the charges on the Gd(III)-DTPA complex start limiting the one-dimensional growth of the BTA-based discotic once a certain size is reached. At millimolar concentrations the formed aggregate has a spherical shape and a diameter of around 5 nm as inferred from 1H-NMR spectroscopy, small angle X-ray scattering, and cryogenic transmission electron microscopy (cryo-TEM). The strength of the electrostatic repulsive interactions between molecules can be reduced by increasing the salt concentration of the buffered solutions. This screening of the charges induces a transition from spherical aggregates into elongated rods with a length &gt; 25 nm. Cryo-TEM allows to visualise the changes in shape and size. In addition, CD spectroscopy permits to derive the mechanistic details of the self-assembly processes before and after the addition of salt. Importantly, the cooperativity -a key feature that dictates the physical properties of the produced supramolecular polymers- increases dramatically upon screening the electrostatic interactions. This increase in cooperativity results in a significant increase in the molecular weight of the formed supramolecular polymers in water.

The goal of this experiment is to determine and control the size, shape and stability of self-assembled discotic amphiphiles in water. For aqueous based supramolecular polymers such level of control is very difficult. We apply a strategy using both repulsive and attractive interactions. The experimental techniques applied to characterize this system are broadly applicable.

Su Supramoleküler Polimerlerin Boyut, Şekil ve Stabilite Kontrolü

For aqueous based supramolecular polymers, the simultaneous control over shape, size and stability is very difficult1. At the same time, the ability to do ...

Mühendislik

Production of Disulfide-stabilized Transmembrane Peptide Complexes for Structural Studies

Physical interactions among the lipid-embedded alpha-helical domains of membrane proteins play a crucial role in folding and assembly of membrane protein complexes and in dynamic processes such as transmembrane (TM) signaling and regulation of cell-surface protein levels. Understanding the structural features driving the association of particular sequences requires sophisticated biophysical and biochemical analyses of TM peptide complexes. However, the extreme hydrophobicity of TM domains makes them very difficult to manipulate using standard peptide chemistry techniques, and production of suitable study material often proves prohibitively challenging. Identifying conditions under which peptides can adopt stable helical conformations and form complexes spontaneously adds a further level of difficulty. Here we present a procedure for the production of homo- or hetero-dimeric TM peptide complexes from materials that are expressed in E. coli, thus allowing incorporation of stable isotope labels for nuclear magnetic resonance (NMR) or non-natural amino acids for other applications relatively inexpensively. The key innovation in this method is that TM complexes are produced and purified as covalently associated (disulfide-crosslinked) assemblies that can form stable, stoichiometric and homogeneous structures when reconstituted into detergent, lipid or other membrane-mimetic materials. We also present carefully optimized procedures for expression and purification that are equally applicable whether producing single TM domains or crosslinked complexes and provide advice for adapting these methods to new TM sequences.

Biophysical and biochemical studies of interactions among membrane-embedded protein domains face many technical challenges, the first of which is obtaining appropriate study material. This article describes a protocol for producing and purifying disulfide-stabilized transmembrane peptide complexes that are suitable for structural analysis by solution nuclear magnetic resonance (NMR) and other analytical applications.

Yapısal Çalışmaları üretimi disülfid stabilize Transmembran Peptit Kompleksi

Physical  interactions among the lipid-embedded alpha-helical domains of membrane  proteins play a crucial role in folding and assembly of membrane ...

Kimya

Compact Quantum Dots for Single-molecule Imaging

Single-molecule imaging is an important tool for understanding the mechanisms of biomolecular function and for visualizing the spatial and temporal heterogeneity of molecular behaviors that underlie cellular biology 1-4. To image an individual molecule of interest, it is typically conjugated to a fluorescent tag (dye, protein, bead, or quantum dot) and observed with epifluorescence or total internal reflection fluorescence (TIRF) microscopy. While dyes and fluorescent proteins have been the mainstay of fluorescence imaging for decades, their fluorescence is unstable under high photon fluxes necessary to observe individual molecules, yielding only a few seconds of observation before complete loss of signal. Latex beads and dye-labeled beads provide improved signal stability but at the expense of drastically larger hydrodynamic size, which can deleteriously alter the diffusion and behavior of the molecule under study.
Quantum dots (QDs) offer a balance between these two problematic regimes. These nanoparticles are composed of semiconductor materials and can be engineered with a hydrodynamically compact size with exceptional resistance to photodegradation 5. Thus in recent years QDs have been instrumental in enabling long-term observation of complex macromolecular behavior on the single molecule level. However these particles have still been found to exhibit impaired diffusion in crowded molecular environments such as the cellular cytoplasm and the neuronal synaptic cleft, where their sizes are still too large 4,6,7.
Recently we have engineered the cores and surface coatings of QDs for minimized hydrodynamic size, while balancing offsets to colloidal stability, photostability, brightness, and nonspecific binding that have hindered the utility of compact QDs in the past 8,9. The goal of this article is to demonstrate the synthesis, modification, and characterization of these optimized nanocrystals, composed of an alloyed HgxCd1-xSe core coated with an insulating CdyZn1-yS shell, further coated with a multidentate polymer ligand modified with short polyethylene glycol (PEG) chains (Figure 1). Compared with conventional CdSe nanocrystals, HgxCd1-xSe alloys offer greater quantum yields of fluorescence, fluorescence at red and near-infrared wavelengths for enhanced signal-to-noise in cells, and excitation at non-cytotoxic visible wavelengths. Multidentate polymer coatings bind to the nanocrystal surface in a closed and flat conformation to minimize hydrodynamic size, and PEG neutralizes the surface charge to minimize nonspecific binding to cells and biomolecules. The end result is a brightly fluorescent nanocrystal with emission between 550-800 nm and a total hydrodynamic size near 12 nm. This is in the same size range as many soluble globular proteins in cells, and substantially smaller than conventional PEGylated QDs (25-35 nm).

We describe the preparation of colloidal quantum dots with minimized hydrodynamic size for single-molecule fluorescence imaging. Compared to conventional quantum dots, these nanoparticles are similar in size to globular proteins and are optimized for single-molecule brightness, stability against photodegradation, and resistance to nonspecific binding to proteins and cells.

Tek molekül Görüntüleme için kompakt Kuantum Noktaları

Single-molecule imaging is an important tool for  understanding the mechanisms of biomolecular function and for visualizing the  spatial and temporal ...

Biochemical Measurement of Neonatal Hypoxia

Neonatal hypoxia ischemia is characterized by inadequate blood perfusion of a tissue or a systemic lack of oxygen. This condition is thought to cause/exacerbate well documented neonatal disorders including neurological impairment 1-3. Decreased adenosine triphosphate production occurs due to a lack of oxidative phosphorylation. To compensate for this energy deprived state molecules containing high energy phosphate bonds are degraded 2. This leads to increased levels of adenosine which is subsequently degraded to inosine, hypoxanthine, xanthine, and finally to uric acid. The final two steps in this degradation process are performed by xanthine oxidoreductase. This enzyme exists in the form of xanthine dehydrogenase under normoxic conditions but is converted to xanthine oxidase (XO) under hypoxia-reperfusion circumstances 4, 5. Unlike xanthine dehydrogenase, XO generates hydrogen peroxide as a byproduct of purine degradation 4, 6. This hydrogen peroxide in combination with other reactive oxygen species (ROS) produced during hypoxia, oxidizes uric acid to form allantoin and reacts with lipid membranes to generate malondialdehyde (MDA) 7-9. Most mammals, humans exempted, possess the enzyme uricase, which converts uric acid to allantoin. In humans, however, allantoin can only be formed by ROS-mediated oxidation of uric acid. Because of this, allantoin is considered to be a marker of oxidative stress in humans, but not in the mammals that have uricase.
We describe methods employing high pressure liquid chromatography (HPLC) and gas chromatography mass spectrometry (GCMS) to measure biochemical markers of neonatal hypoxia ischemia. Human blood is used for most tests. Animal blood may also be used while recognizing the potential for uricase-generated allantoin. Purine metabolites were linked to hypoxia as early as 1963 and the reliability of hypoxanthine, xanthine, and uric acid as biochemical indicators of neonatal hypoxia was validated by several investigators 10-13. The HPLC method used for the quantification of purine compounds is fast, reliable, and reproducible. The GC/MS method used for the quantification of allantoin, a relatively new marker of oxidative stress, was adapted from Gruber et al 7. This method avoids certain artifacts and requires low volumes of sample. Methods used for synthesis of MMDA were described elsewhere 14, 15. GC/MS based quantification of MDA was adapted from Paroni et al. and Cighetti et al. 16, 17. Xanthine oxidase activity was measured by HPLC by quantifying the conversion of pterin to isoxanthopterin 18. This approach proved to be sufficiently sensitive and reproducible.

A method is described to measure biochemical markers of neonatal hypoxia-ischemia. The approach utilizes high pressure liquid chromatography (HPLC) and Gas Chromatography Mass Spectrometry (GC/MS).

Yenidoğan Hipoksi Biyokimyasal Ölçüm

Neonatal hypoxia ischemia is characterized by inadequate blood perfusion of a tissue or a systemic lack of oxygen. This condition is thought to ...

Tıp

Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

Paramagnetic complexes of gadolinium(III) with acyclic or macrocyclic chelates are the most commonly used contrast agents (CAs) for magnetic resonance imaging (MRI). Their purpose is to enhance the relaxation rate of water protons in tissue, thus increasing the MR image contrast and the specificity of the MRI measurements. Current clinically approved contrast agents are low molecular weight molecules that are rapidly cleared from the body. The use of dendrimers as carriers of paramagnetic chelators can play an important role in the future development of more efficient MRI contrast agents. Specifically, the increase in local concentration of the paramagnetic species results in a higher signal contrast. Furthermore, this CA provides a longer tissue retention time due to its high molecular weight and size. Here, we demonstrate a convenient procedure for the preparation of macromolecular MRI contrast agents based on poly(amidoamine) (PAMAM) dendrimers with monomacrocyclic DOTA-type chelators (DOTA &#8211; 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate). The chelating unit was appended by exploiting the reactivity of the isothiocyanate (NCS) group towards the amine surface groups of the PAMAM dendrimer to form thiourea bridges. Dendrimeric products were purified and analyzed by means of nuclear magnetic resonance spectroscopy, mass spectrometry, and elemental analysis. Finally, high resolution MR images were recorded and the signal contrasts obtained from the prepared dendrimeric and the commercially available monomeric agents were compared.

Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

This protocol describes the preparation and characterization of a dendrimeric magnetic resonance imaging (MRI) contrast agent that carries cyclen-based macrocyclic chelates coordinating paramagnetic gadolinium ions. In a series of MRI experiments in vitro, this agent produced an amplified MRI signal when compared to the commercially available monomeric analogue.

Hazırlama ve<em&gt; İn Vitro</em&gt; Manyetik Rezonans Görüntüleme için Dendrimer tabanlı Kontrast Ajanlar Karakterizasyonu

Paramagnetic complexes of gadolinium(III) with acyclic or macrocyclic chelates are the most commonly used contrast agents (CAs) for magnetic resonance ...

Continuous Flow Chemistry: Reaction of Diphenyldiazomethane with p-Nitrobenzoic Acid

Continuous flow technology has been identified as instrumental for its environmental and economic advantages leveraging superior mixing, heat transfer and cost savings through the &#34;scaling out&#34; strategy as opposed to the traditional &#34;scaling up&#34;. Herein, we report the reaction of diphenyldiazomethane with p-nitrobenzoic acid in both batch and flow modes. To effectively transfer the reaction from batch to flow mode, it is essential to first conduct the reaction in batch. As a consequence, the reaction of diphenyldiazomethane was first studied in batch as a function of temperature, reaction time, and concentration to obtain kinetic information and process parameters. The glass flow reactor set-up is described and combines two types of reaction modules with &#34;mixing&#34; and &#34;linear&#34; microstructures. Finally, the reaction of diphenyldiazomethane with p-nitrobenzoic acid was successfully conducted in the flow reactor, with up to 95% conversion of the diphenyldiazomethane in 11 min. This proof of concept reaction aims to provide insight for scientists to consider flow technology&#39;s competitiveness, sustainability, and versatility in their research.

Continuous Flow Chemistry: Reaction of Diphenyldiazomethane with p-Nitrobenzoic Acid

Flow chemistry carries environmental and economic advantages by leveraging superior mixing, heat transfer and cost benefits. Herein, we provide a blueprint to transfer chemical processes from batch to flow mode. The reaction of diphenyldiazomethane (DDM) with p-nitrobenzoic acid, conducted in batch and flow, was chosen for proof of concept.

Sürekli akışı kimya: Diphenyldiazomethane p- Nitrobenzoic asit tepki

Continuous flow technology has been identified as instrumental for its environmental and economic advantages leveraging superior mixing, heat transfer and ...

Fabricating Reactive Surfaces with Brush-like and Crosslinked Films of Azlactone-Functionalized Block Co-Polymers

In this paper, fabrication methods that generate novel surfaces using the azlactone-based block co-polymer, poly (glycidyl methacrylate)-block-poly (vinyl dimethyl azlactone) (PGMA-b-PVDMA), are presented. Due to the high reactivity of azlactone groups towards amine, thiol, and hydroxyl groups, PGMA-b-PVDMA surfaces can be modified with secondary molecules to create chemically or biologically functionalized interfaces for a variety of applications. Previous reports of patterned PGMA-b-PVDMA interfaces have used traditional top-down patterning techniques that generate non-uniform films and poorly controlled background chemistries. Here, we describe customized patterning techniques that enable precise deposition of highly uniform PGMA-b-PVDMA films in backgrounds that are chemically inert or that have biomolecule-repellent properties. Importantly, these methods are designed to deposit PGMA-b-PVDMA films in a manner that completely preserves azlactone functionality through each processing step. Patterned films show well-controlled thicknesses that correspond to polymer brushes (~90 nm) or to highly crosslinked structures (~1-10 &#956;m). Brush patterns are generated using either the parylene lift-off or interface directed assembly methods described and are useful for precise modulation of overall chemical surface reactivity by adjusting either the PGMA-b-PVDMA pattern density or the length of the VDMA block. In contrast, the thick, crosslinked PGMA-b-PVDMA patterns are obtained using a customized micro-contact printing technique and offer the benefit of higher loading or capture of secondary material due to higher surface area to volume ratios. Detailed experimental steps, critical film characterizations, and trouble-shooting guides for each fabrication method are discussed.

Surface fabrication methods for patterned deposition of nanometer thick brushes or micron thick, crosslinked films of an azlactone block co-polymer are reported. Critical experimental steps, representative results, and limitations of each method are discussed. These methods are useful for creating functional interfaces with tailored physical features and tunable surface reactivity.

Fırça benzeri ile reaktif yüzeyler imalatı ve Azlactone Functionalized blok ortak polimerler çapraz filmleri

In this paper, fabrication methods that generate novel surfaces using the azlactone-based block co-polymer, poly (glycidyl methacrylate)-block-poly (vinyl ...

Exploring the Arginine Methylome by Nuclear Magnetic Resonance Spectroscopy

Protein-bound arginine is commonly methylated in many proteins and regulates their function by altering the physicochemical properties, their interaction with other molecules, including other proteins or nucleic acids. This work presents an easily implementable protocol for quantifying arginine and its derivatives, including asymmetric and symmetric dimethylarginine (ADMA and SDMA, respectively) and monomethyl arginine (MMA). Following protein isolation from biological body fluids, tissues, or cell lysates, a simple method for homogenization, precipitation of proteins, and protein hydrolysis is described. Since the hydrolysates contain many other components, such as other amino acids, lipids, and nucleic acids, a purification step using solid-phase extraction (SPE) is essential. SPE can either be performed manually using centrifuges or a pipetting robot. The sensitivity for ADMA using the current protocol is about 100 nmol/L. The upper limit of detection for arginine is 3 mmol/L due to SPE saturation. In summary, this protocol describes a robust method, which spans from biological sample preparation to NMR-based detection, providing valuable hints and pitfalls for successful work when studying the arginine methylome.

The present protocol describes the preparation and quantitative measurement of free and protein-bound arginine and methyl-arginines by 1H-NMR spectroscopy.

Arginin Metilomunun Nükleer Manyetik Rezonans Spektroskopisi ile Araştırılması

Protein-bound arginine is commonly methylated in many proteins and regulates their function by altering the physicochemical properties, their interaction ...

Kanser Araştırmaları

Evaluation of Oxidative Stress in Biological Samples Using the Thiobarbituric Acid Reactive Substances Assay

Despite its limited analytical specificity and ruggedness, the thiobarbituric acid reactive substances (TBARS) assay has been widely used as a generic metric of lipid peroxidation in biological fluids. It is often considered a good indicator of the levels of oxidative stress within a biological sample, provided that the sample has been properly handled and stored. The assay involves the reaction of lipid peroxidation products, primarily malondialdehyde (MDA), with thiobarbituric acid (TBA), which leads to the formation of MDA-TBA2 adducts called TBARS. TBARS yields a red-pink color that can be measured spectrophotometrically at 532 nm. The TBARS assay is performed under acidic conditions (pH = 4) and at 95 &#176;C. Pure MDA is unstable, but these conditions allow the release of MDA from MDA bis(dimethyl acetal), which is used as the analytical standard in this method. The TBARS assay is a straightforward method that can be completed in about 2 h. Preparation of assay reagents are described in detail here. Budget-conscious researchers can use these reagents for multiple experiments at a low cost rather than buying an expensive TBARS assay kit that only permits construction of a single standard curve (and thus can only be used for one experiment). The applicability of this TBARS assay is shown in human serum, low density lipoproteins, and cell lysates. The assay is consistent and reproducible, and limits of detection of 1.1 &#956;M can be reached. Recommendations for the use and interpretation of the spectrophotometric TBARS assay are provided.

The goal of the thiobarbituric acid reactive substances assay is to assess oxidative stress in biological samples by measuring the production of lipid peroxidation products, primarily malondialdehyde, using visible wavelength spectrophotometry at 532 nm. The method described here can be applied to human serum, cell lysates, and low density lipoproteins.

Tiobarbitürik Asit Reaktif Maddeler Tahlil kullanılarak Biyolojik Örneklerde Oksidatif Stresin Değerlendirilmesi

Despite its limited analytical specificity and ruggedness, the thiobarbituric acid reactive substances (TBARS) assay has been widely used as a generic ...

Headspace GC-MS ile Hayvan Kaynaklı İlaçta Trimetilamin Tayini

An Improved Technique for Trimethylamine Detection in Animal-Derived Medicine by Headspace Gas Chromatography-Tandem Quadrupole Mass Spectrometry

Animal-derived medicines have distinctive characteristics and significant curative effects, but most of them have an obvious fishy odor, resulting in the poor compliance of clinical patients. Trimethylamine (TMA) is one of the key fishy odor components in animal-derived medicine. It is difficult to identify TMA accurately using the existing detection method due to the increased pressure in the headspace vial caused by the rapid acid-base reaction after the addition of lye, which causes TMA to escape from the headspace vial, stalling the research progress of the fishy odor of animal-derived medicine. In this study, we proposed a controlled detection method that introduced a paraffin layer as an isolation layer between acid and lye. The rate of TMA production could be effectively controlled by slowly liquefying the paraffin layer through thermostatic furnace heating. This method showed satisfactory linearity, precision experiments, and recoveries with good reproducibility and high sensitivity. It provided technical support for the deodorization of animal-derived medicine.

Yazar Spot Işığı: Headspace Gaz Kromatografisi-Tandem Dört Kutuplu Kütle Spektrometresi ile Hayvan Kaynaklı Tıbbında Trimetilamin Tespiti için Geliştirilmiş Bir Teknik  

Here, a headspace gas chromatography-tandem quadrupole mass spectrometry (HS-GC-MS/MS) method suitable for the determination of trimethylamine (TMA) in animal-derived medicines is described. The protocol includes sample pretreatment, headspace treatment, analysis conditions, methodological validation, and the determination of TMA in animal-derived medicines.

Headspace Gaz Kromatografisi-Tandem Dört Kutuplu Kütle Spektrometrisi ile Hayvan Kaynaklı Tıpta Trimetilamin Tayini için Geliştirilmiş Bir Teknik

Animal-derived medicines have distinctive characteristics and significant curative effects, but most of them have an obvious fishy odor, resulting in the ...

DMMTA^V ve çevresel uygulamaları için DMA^V kullanarak DMDTA^V hazırlanması: sentez, arıtma ve onay

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