Determination of diacetyl in workplace air by high performance liquid chromatography using 4-nitro-o-phenylenediamine as precolumn derivatization / 环境与职业医学

Background Diacetyl (DC) is widely used in the food flavoring industry and excessive occupational exposure to DC can cause serious respiratory diseases. However, there is no corresponding national standard method for the determination of DC in the air of workplace. Objective To establish a method for the determination of DC in workplace air by high performance liquid chromatography using 4-nitro-o-phenylenediamine (NPDA) as precolumn derivatization. Methods DC in the air of workplace was collected by solution absorption method. This experiment used NPDA as the derivatization reagent. By adjusting acidity of solution and optimizing concentration ration of DC/NPDA, derivatization temperature, and time, a method for the determination of DC in workplace air was proposed, and its performance indexes such as linearity, detection limit, and lower limit of quantification were obtained. Sampling efficiency was evaluated by relative comparison method, and sample stability was evaluated by sample preservation test. Accuracy and precision of the method were evaluated by standard addition recovery test with blank samples, and an interference test was carried out by adding standard samples. The established method was applied to actual samples to evaluate its adaptability. Results A combination of 60 °C for 2 h was selected for derivatization because a higher derivatization reaction temperature and a longer reaction time associated with a higher derivatization efficiency. The solution was separated by SB-C18 column (250 mm×4.6 mm, 5 μm) at 30 ℃, using a mixture of methanol and water (v/v, 65%/35%) as mobile phase with an elution flow rate of 1.0 mL·min−1, and was detected with a variable wavelength detector (λmax=257 nm) by qualitative analysis based on retention time and quantitative analysis based on external standard method. In terms of the proposed method, the linear range of detection was from 5 μg·L−1 to 2000 μg·L−1, with a correlation coefficient of 0.9999, and a detection limit of 1.3 μg·L−1, the quantitative detection of the lower limit was 4.3 μg·L−1, with a sampling volume V0 of 3.0 L, the minimum detection concentration was 4.3 μg·m−3, and the minimum quantitative concentration was 14.3 μg·m−3. The recovery rate was 99.1%-100.8%, the intra-batch precision was 0.5%-3.0%, and the inter-batch precision was 1.2%-2.0%. The average sampling efficiency of this method was 94.5%, and the sample could be stored at 4 °C for at least 14 d. The coexisting components in the air of the workplace did not interfere with the determination of DC. The DC content in the air of a flavor workplace was 5.86-8.85 mg·m−3. Conclusion A determination method for DC in workplace air by high performance liquid chromatography using NPDA as precolumn derivatization after being collected by 1.0% phosphoric acid absorbent is proposed and has the advantages of simple operation, high sensitivity, and good accuracy. With no DC loss and degradation, the method may satisfy the request for DC determination in the air of workplace.

Two cases of airway dysfunction related to diacetyl exposure / 中华劳动卫生职业病杂志

Occupational exposure to diacetyl can lead to bronchiolitis obliterans. In this paper, two patients with severe obstructive ventilation disorder who were exposed to diacetyl at a fragrance and flavours factory were analyzed. The clinical manifestations were cough and shortness of breath. One of them showed Mosaic shadows and uneven perfusion in both lungs on CT, while the other was normal. Field investigation found that 4 of the 8 workers in the factory were found to have obstructive ventilation disorder, and 2 had small airway dysfunction. This paper summarizes the diagnostic process of patients in order to improve the understanding of airway dysfunction caused by occupational exposure to diacetyl and promote the development of relevant standards.

Quality markers of Zingiberis Rhizoma Carbonisata before and after processing / 中国中药杂志

Based on the previous research results of our group and literature research, the chemical components, mechanisms, pharmacodynamics, and pharmacokinetics of Zingiberis Rhizoma Carbonisata were summarized to determine the quality markers(Q-markers) of Zingiberis Rhizoma Carbonisata and Zingiberis Rhizoma. Our research group has clarified the differential components of Zingiberis Rhizoma Carbonisata and Zingiberis Rhizoma, the meridian-warming hemostatic effect of Zingiberis Rhizoma Carbonisata, the related targets and pathways of the effect, the endogenous biomarkers of Zingiberis Rhizoma Carbonisata, and the hemodynamic processes of Zingiberis Rhizoma Carbonisata and Zingiberis Rhizoma. Moreover, based on high-performance liquid chromatography-diode array detector-electrospray ionization mass spectrometry(HPLC-DAD-ESIMS), a method for determining the content of Q-mar-kers was established. In conclusion, the study finally determined that gingerone, 6-shogaol, and diacetyl-6-gingerol were the Q-mar-kers of Zingiberis Rhizoma Carbonisata decoction pieces, and 6-gingerol, 8-gingerol, and 10-gingerol were Q-markers of Zingiberis Rhizoma decoction pieces. The result is expected to provide a reference for the establishment of quality standards for Zingiberis Rhizoma Carbonisata decoction pieces and Zingiberis Rhizoma decoction pieces.

Comparison of establishment of bronchiolitis obliterans murine model by oropharyngeal aspiration and intratracheal instillation of diacetyl / 西安交通大学学报(医学版)

Objective To compare the different methods of administration of diacetyl (DA)-established bronchiolitis obliterans (BO)murine model so as to establish a simple,easy-to-operate and stable BO murine model. Methods SPF grade C57BL/6 male mice (6 to 8 weeks)were randomly divided into four groups with 10 mice in each group:oropharyngeal aspiration group (OPR),intratracheal instillation group (ITI),and control groups (OPR-CON and ITI-CON).OPR group was treated with DA (400 mg/kg,327 mg/kg)by oropharyngeal aspiration;ITI group received DA (400 mg/kg,327 mg/mL)through intratracheal instillation;OPR-CON group and ITI-CON group were treated with sterilized distilled water instead of DA,while the other experimental conditions were the same as those in OPR and ITI groups.The mice were kept in SPF-class animal center for 7 d to collect specimens. Collected bronchoalveolar lavage fluid (BALF)and the left lung were examined pathologically.Results Male C57 BL/6 mice were treated with a single dose of DA (400 mg/kg,327 mg/kg)by OPR or ITI,which could establish BO model.The successful model was evaluated by pulmonary function,BALF counts and pathological examination. Airway hyperresponsiveness occurred with the two-method resulted BO.And two methods of instilling DA resulted in airway injury,lumen occlusion,infiltration of inflammatory cells in the airway and around the vessels.The mortality rate of mice was up to 60% and the success of model construction was only 20% in BO model by oropharyngeal aspiration of DA,while that in ITI group mortality was only 30%,the success of model construction was up to 60%.There was no death in control groups.Conclusion BO murine model could be successfully established by OPR or ITI of DA (400 mg/kg,327 mg/mL).However,the BO model was established well by ITI of DA with lower mortality rate.Therefore,ITI of DA-established BO murine model is recommended for use.

An original method for producing acetaldehyde and diacetyl by yeast fermentation

Abstract In this study a natural culture medium that mimics the synthetic yeast peptone glucose medium used for yeast fermentations was designed to screen and select yeasts capable of producing high levels of diacetyl and acetaldehyde. The presence of whey powder and sodium citrate in the medium along with manganese and magnesium sulfate enhanced both biomass and aroma development. A total of 52 yeasts strains were cultivated in two different culture media, namely, yeast peptone glucose medium and yeast acetaldehyde-diacetyl medium. The initial screening of the strains was based on the qualitative reaction of the acetaldehyde with Schiff's reagent (violet color) and diacetyl with Brady's reagent (yellow precipitate). The fermented culture media of 10 yeast strains were subsequently analyzed by gas chromatography to quantify the concentration of acetaldehyde and diacetyl synthesized. Total titratable acidity values indicated that a total titratable acidity of 5.5 °SH, implying culture medium at basic pH, was more favorable for the acetaldehyde biosynthesis using strain D15 (Candida lipolytica; 96.05 mg L-1 acetaldehyde) while a total titratable acidity value of 7 °SH facilitated diacetyl flavor synthesis by strain D38 (Candida globosa; 3.58 mg L-1 diacetyl). Importantly, the results presented here suggest that this can be potentially used in the baking industry.

Chemical constituents from Bidens bipinnata / 中草药

Objective: To study the chemical constituents from the herbs of Bidens bipinnata. Methods: The compounds were isolated and purified by various column chromatographies. Their structures were elucidated by means of physicochemical properties and spectral analyses (MS, 1H-NMR, and 13C-NMR). Results: Eighteen compounds were isolated from 95% ethanol extract of B. bipinnata and identified as quercetin-5-O-β-D-glucopyranoside (1), okanin-4′-O-β-D-(2″, 4″, 6″-triacetyl)-glucopyranoside (2), okanin-4′-O-β-D-(3″, 4″-diacetyl-6″-trans-p-coumaroyl)-glucopyranoside (3), luteolin-7-O-β-D-glucopyranoside (4), kaempferol-7-O-β-D-glucopyranoside (5), kaempferol-3-O-β-D-rutinoside (6), quercetin-3-O-β-D-glucopyranoside (7), quercetin-7-O-β-D-glucopyranoside (8), hyperoside (9), rutin (10), naringenin (11), apigenin (12), quercetin (13), 5, 7-dihydroxy chromone-7-O-β-D-glucoside (14), caffeic acid (15), gallic acid (16), β-sitosterol (17), and sitosterol-3-O-glucopyranoside (18). Conclusion: Compounds 1 and 11 are obtained from the plants in Bidens L. for the first time, and compounds 3-7, 14, 15, and 18 are firstly obtained from this plant.

Bronquiolite associada à exposição a aroma artificial de manteiga em trabalhadores de uma fábrica de biscoitos no Brasil / Bronchiolitis associated with exposure to artificial butter flavoring in workers at a cookie factory in Brazil

OBJETIVO: Relatar quatro casos de bronquiolite decorrente de exposição a aroma artificial de manteiga em uma fábrica de biscoitos no Brasil. MÉTODOS: Descrevemos os achados clínicos, espirométricos e tomográficos nos quatro pacientes, assim como achados de biópsia pulmonar em um dos pacientes. RESULTADOS: Os quatro pacientes eram homens jovens, não fumantes, e desenvolveram obstrução persistente ao fluxo aéreo (relação VEF1/CVF reduzida e VEF1 de 25-44% do previsto) após 1-3 anos de exposição a diacetil, sem a utilização de equipamentos de proteção individual, em uma fábrica de biscoitos. A TCAR mostrou achados indicativos de bronquiolite. Em um paciente, a biópsia pulmonar cirúrgica mostrou bronquiolite obliterante associada a células gigantes. CONCLUSÕES: A bronquiolite decorrente de exposição a flavorizantes artificiais deve ser considerada em trabalhadores com obstrução ao fluxo aéreo no Brasil.

OBJECTIVE: To report the cases of four patients with bronchiolitis caused by exposure to artificial butter flavoring at a cookie factory in Brazil. METHODS: We described the clinical, tomographic, and spirometric findings in the four patients, as well as the lung biopsy findings in one of the patients. RESULTS: All four patients were young male nonsmokers and developed persistent airflow obstruction (reduced FEV1/FVC ratio and FEV1 at 25-44% of predicted) after 1-3 years of exposure to diacetyl, without the use of personal protective equipment, at a cookie factory. The HRCT findings were indicative of bronchiolitis. In one patient, the surgical lung biopsy revealed bronchiolitis obliterans accompanied by giant cells. CONCLUSIONS: Bronchiolitis resulting from exposure to artificial flavoring agents should be included in the differential diagnosis of airflow obstruction in workers in Brazil.

A New Triterpenoid Saponin from Aidi Injection / 中草药·英文版

ObjectiveTo investigate the chemical constituents from Aidi Injection.Methods The chemical constituents were isolated by chromatography on Sephadex LH-20 gel columns and reverse phase semi-preparative HPLC repeatedly.Their structures were identified by spectroscopic analysis (NMR and MS).ResultsTwenty-two compounds were isolated and identified to be 3-O-3',4'-diacetyl-β-D-xylopyranosyl-6-O-β-D-glucopyranosylcycloastragenol (1),astragaloside IV (2),astragaloside Ⅱ (3),astragaloside I (4),isoastragaloside I (5),acetylastragaloside I (6),ginsenosid Re (7),ginsenoside Rf (8),ginsenoside Rg1 (9),ginsenoside Rb3 (10),notoginsenoside R4 (11),ginsenoside Rb1 (12),ginsenoside Rc (13),ginsenoside Rb2 (14),ginsenoside Rd (15),lucyoside H (16),3-O-ββ-D-glucopyranosyl(l→4)-β-D-glucopyranosyl(l→3)-α-L-rhamnopyranosyl (1→2)-α-Larabinopyranosyl oleanolic acid 28-O-α-L-rhamnopyranosyl(l→4)-β-D-glucopyranosyl(1→6)-β-D-glucopyranoside (17),3-O-β-D-glucopyranosyl(1→3)-α-L-rhamnopyranosyl [β-D-glucopyranosyl-(l→4)]-(l→2)-αt-L-arabinopyranosyl oleanolic acid 28-O-α-L-arabinopyranosyl(1→4)-β-D-glucopyranosyl(1→6)-β-D-glucopyranoside (18),syringin (19),elentheroside E (20),4-(1,2,3-trihydroxypropyl)-2,6-dimethoxyphenyl-I-O-β-D-glucopyranoside (21),and coniferin (22).ConclusionCompounds 1-6 are originated from Astragalus membranceus,compounds 7-18 are originated from Panax ginseng,and compounds 19-22 are originated from Acanthopanax senticosus by LC-MS analysis.Compound 1 is a new compound.

Sensitive spectrophotometric determination of thorium (IV) using diacetyl monoxime isonicotinoyl hydrazone (DMIH).

Thorium (IV) forms a yellow Coloured water soluble complex with Diacetyl Monoxime Isonicotinoyl hydrazone (DMIH) reagent in acidic buffer of PH 5.0 with λ max at 352 nm. The molar absorptivity and sandell’s sensitivity are 2.265 X 10 4 L mol -1 cm -1 and 0.0022μg /cm2 respectively. The Beer’s law validity range 1.16–13.92 μg / mL. Thorium (IV) forms (M: L) 1:1 complex with DMIH and stability constant of the complex is 7.0265 X 10 6.The derivative spectrophotometric determination of Th (IV)) was carried out by measuring peak height method. The developed derivative spectrophotometric method was employed for the determination of Thorium (IV) in synthetic samples of alloy. The effect of various diverse ions was also studied.

Assessment of the antimicrobial activity of lactic acid bacteria isolated from two fermented maize products - ogi and kunnu-zaki

The lactic acid bacteria (LAB) used in this study were isolated from two traditional fermented maize products- ogi and kunnu-zaki. The antimicrobial activities of the isolated LAB against some indicator organisms (Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, Proteus mirabilis and Bacillus cereus) was investigated. The LAB population in the ogi samples ranged from 5.39 log cfu/g to 6.40 log cfu/g while that of kunnu-zaki ranged from 6.11 log cfu/g to 6.70 log cfu/g. The lactic acid bacteria isolated were identified as Lactobacillus plantarum, L. fermentum, L. lactis, L. acidophilus, L. mesenteroides, L. casei, and Streptococcus thermophilus. Cell free supernatant of the LAB was able to inhibit the growth of the indicator organism used. The largest zone of inhibition was 11 mm produced by L. plantarum against Klebsiella pnuemoniae while the least zone of inhibition was 3 mm produced by L. acidophilus against E. coli. The LAB tested also produced various antimicrobial compounds such as lactic acid, diacetyl and hydrogen peroxide and quantitative estimation of these antimicrobial compounds was carried out. The highest yield of lactic acid was 2.18 g/L produced by S. thermophilus, highest yield of diacetyl was 2.5 g/L produced by L. plantarum while the highest yield of hydrogen peroxide was 0.006 g/L produced by L. plantarum.

Mecanismo de oxidação aeróbica de acetoacetato e 2-metilacetoacetato catalisada por mioglobina: implicações em desordens cetogênicas / Mechanism of the aerobic oxidation of acetoacetate and 2- methylacetoacetate catalyzed by Mb: implications for ketogenic disorders

Acetoacetato (AA) e 2-metilacetoacetato (MAA) são compostos β-cetoácidos acumulados em diversas desordens metabólicas como no diabetes e na isoleucinemia, respectivamente. Examinamos o mecanismo de oxidação aeróbica de AA e MAA iniciada por intermediários reativos de mioglobina de coração de cavalo (Mb) gerados pela adição de H2O2. Uma rota quimioluminescente que envolve um intermediário dioxetânico cuja termólise gera espécies α-dicarbonílicas (metilglioxal e biacetilo) foi proposta e estudada. Emissão de luz ultra fraca acompanha a reação, e sua intensidade aumenta linearmente pelo aumento da concentração tanto de Mb (10-500 µM) quando AA (10-100 mM). Estudos de consumo de oxigênio mostraram que MAA é, como esperado, quase uma ordem de grandeza mais reativo que AA. Estudos de EPR com captação de spin, utilizando MNP, possibilitaram detectar adutos de MAA atribuíveis a um radical centrado no Cα (aN = 1.55 mT) e ao radical acetila (aN = 0.83 mT). O sinal do radical acetila é totalmente suprimido por sorbato, um conhecido e eficiente supressor de espécies tripletes, o que é consistente com uma rota reacional envolvendo um intermediário dioxetânico. Clivagem-α da ligação carbonila-carbonila do produto biacetilo triplete produziria, de fato, radicais acetila. Além disso, utilizando AA como substrato para Mb/H2O2, um sinal de EPR atribuível ao aduto MNP-AA• (aN = 1.46 mT e aH = 0.34 mT) foi observado e confirmado por efeito isotópico. O consumo de oxigênio e o rendimento de compostos α-dicarbonílicos foram dose-dependentes à concentração de AA ou MAA (1-50 mM) bem como à concentração de H2O2 adicionado às misturas de reação contendo Mb (até 1:10 quando medido o consumo de oxigênio, e até 1:25 quando medido o rendimento de compostos α-dicarbonílicos) e tert-butilhidroperóxido (até 1:200). Os perfis de pH (5,8-7,8) para consumo de oxigênio e rendimento de compostos α-dicarbonílicos mostraram maiores rendimentos para baixos valores de pH, indicativo de ferrilMb...

Acetoacetate (AA) and 2-methylacetoacetate (MAA) are β-ketoacids accumulated in several metabolic disorders such as diabetes and isoleucinemia, respectively. Here we examine the mechanism of AA and MAA aerobic oxidation initiated by the reactive enzyme intermediates formed by the reaction of muscle horse myoglobin (Mb) with H2O2. A chemiluminescent route involving a dioxetane intermediate whose thermolysis yields triplet α-dicarbonyl species (methylglyoxal and diacetyl) is envisaged. Accordingly, the ultraweak light emission that accompanies the reaction increases linearly by raising the concentration of both Mb (10-500 µM) and AA (10- 100 mM). Oxygen uptake studies revealed that MAA is, expectedly, almost one order of magnitude more reactive than AA. EPR spin-trapping studies with MNP detected spin adducts from MAA attributable to an α-carbon-centered radical (aN = 1.55 mT) and to an acetyl radical (aN = 0.83 mT). As the acetyl radical signal is totally suppressed by sorbate, a well-known efficient triplet species quencher, the dioxetane hypothesis seems to be reliable. The α-cleavage of the carbonyl-carbonyl bond of a putative excited triplet diacetyl product would, in fact, leads to an acetyl radical. Furthermore, using AA as substrate for Mb/H2O2, an EPR signal assignable to a MNP-AA• adduct (aN = 1.46 mT and aH = 0.34 mT) was observed and confirmed by isotope effect. Oxygen consumption and α-dicarbonyl yield were also dependent on AA or MAA concentrations (1-50 mM) as well as on the concentration of peroxide added to the Mb-containing reaction mixtures: H2O2 (up to 1:10 when measuring oxygen uptake and up to 1:25 when measuring the α-dicarbonyl yield) and t-butOOH (up to 1:200). The pH profiles (5.8-7.8) of oxygen consumption and α-dicarbonyl yield show higher reaction rates at lower pHs, indicative of a ferrylMb intermediate. Evaluating Mb lesion, both β-ketoacids reduced disorganization of the secondary and tertiary protein structure elicited by H2O2...

A new derivative of dihydroochnaflavone isolated from Luxemburgia species (Ochnaceae) and the complete ¹H and 13C NMR chemical shifts assignments / Um novo derivado da dihidroochnaflavona isolada de Luxemburgia species (Ochnaceae) e o completo assinalamento dos dados de RMN de ¹H e 13C

The biflavonoid 2",3"-dihydroochnaflavone, isolated from the Luxemburgia species (Ochanaceae), was treated with diazomethane to obtain the trimethyl-ether that was treated with pyridine/acetic anhydride to yield a new derivative, 5-acetil-7,4'-dimethyl-flavone-(3'→O-4'")-5"-acetil-7"-methyl-flavanone. The complete ¹H and 13C NMR data assignments of the new derivative were made by the one- and two-dimensional spectral analysis.

O biflavonóide 2",3"-diidroochnaflavona, isolada de espécies de Luxemburgia (Ochanaceae), foi tratada com diazometano e forneceu o éter trimetílico que, em seguida, foi tratado com anidrido acético/piridina obtendo-se um novo derivado, 5-acetil-7,4'-dimetil-flavona-(3'→O-4'")-5"-acetil-7"-metil-flavanona. Fez-se o completo assinalamento dos dados de RMN ¹H e 13C através da análise dos espectros uni- e bidimensionais do derivado.

Evaluation of Dermal Measurement for Workers in Benzidine Dihydrochloride and Benzidine Based Dye Manufacturing Factory / 대한산업의학회지

This study is performed to evaluate usefulness of dermal measurement of benzidine and benzidine based dye as one of the occupational exposure assessment method for these compounds. We selected one benzidine manufacturing factory and one dye manufacturing factory in Incheon area. Eleven workers were for benzidine manufacturing factory and twenty four for dye. We analyzed relationships among air level, amount on skin and concentration of urinary metabolites for these compounds. Airborne levels of benzidine and dye were measured by NIOSH 5509, 5013 methods. Amount of these compounds on skin was measured with skin wipe method. Concentration of benzidine metabolites in urine was measured by High Performance Liquid Chromatography after alkaline hydrolysis. The amount of benzidine on hand skin was 25.05( - 233.2) ng/ur, and the amount of the neck was 2.01 ( - 11.9) ng/cm2 in the benzidine dihydrochloride manufacturing factory. The amount of benzidine on hand and neck skin has positive correlation with concentration of urinary monoacetyl benzidine (r=0.644, p < 0.05) . The amount of benzidine based dye on hand skin was 55.75( - 457.7) ng/cm2, and the amount of the neck skin was 18( - 284.7) ng/cm in benzidine based dye manufacturing factory The amount of dye on hand and neck skin has positive correlation with concentration of urinary benzidine for dye workers (r=0.467, p < 0.05). When assessing the exposure of workers who deal with benzidine, the amount of benzidine on skin should be measured for an accurate exposure assessment.