نتایج جستجو برای: Headspace

تعداد نتایج: 2540  

2004
Derrick C. Wood James M. Miller

2 Headspace sampling for gas chromatographic (GC) analysis has many advantages, the most important of which is the elimination of many interferences from the sample matrix. In addition to the standard methods for headspace sampling, the technique of solid-phase microextraction (SPME) has found wide acceptance because it is simple and inexpensive. More recently, single-drop microextraction (SDME...

2012

The determination of VOCs is widely used in many fields of chemistry. Two common sample preparation techniques for this analysis are static and dynamic headspace. Static headspace is a relatively simple sampling method that is dependent upon the formation of equilibrium conditions in a closed system. Dynamic headspace continually sweeps the headspace of the sample concentrating the analytes ont...

Journal: :Journal of agricultural and food chemistry 1999
G Mazza T Cottrell

The headspace volatile components of roots, stems, leaves, and flowers of Echinacea angustifolia,E. pallida, and E. purpurea were analyzed by capillary gas chromatography/mass spectrometry (GC/MS). Over 70 compounds were identified in the samples. All plant tissues, irrespective of the species, contain acetaldehyde, dimethyl sulfide, camphene, hexanal, beta-pinene, and limonene. The main headsp...

Journal: :Early intervention in psychiatry 2015
Debra Rickwood Nina Van Dyke Nic Telford

AIM headspace centres comprise a significant innovation in community-based youth mental health service delivery in Australia. This paper examines the service activity of the first headspace centres to determine common and unique practice characteristics across headspace centres in this new approach to mental health service delivery. METHODS Data come from quarterly progress reports provided b...

Journal: :Molecules 2012
Igor Jerković Dajana Gašo-Sokač Hrvoje Pavlović Zvonimir Marijanović Mirko Gugić Ivana Petrović Spomenka Kovač

GC and MS were used for the analysis of Croatian Centaurium erythraea Rafn essential oil (obtained by hydrodistillation) and headspace (applying headspace solid-phase microextraction). The headspace contained numerous monoterpene hydrocarbons (the major ones were terpinene-4-ol, methone, p-cymene, γ-terpinene and limonene). Oxygenated monoterpenes were present in the headspace and oil, while 1,...

Journal: :Talanta 2005
Tzu-Yun Chu Chau-Chin Hung Chung-Yuan Hsu

A simple and efficient technique that does not require solvent and uses less operating time for the investigation of sex pheromones of the carambola fruit borer (Eucosma notanthes Meyrick) by utilizing headspace solid-phase microextraction (SPME) followed by GC-MS analysis has been developed. Variables such as types of SPME fiber, number of pests, temperature and extraction time have been studi...

2012
Headspace Sampler Wenwen Shen Chunxiao Wang

A multiple headspace extraction (MHE) method using the Agilent 7697A Headspace Sampler coupled with an Agilent 7890A Gas Chromatograph has been developed for quantitative determination of residual monomers and solvents in polystyrene pellets. The polystyrene pellets were freeze-ground before analysis by the MHE procedure. The optimization of headspace temperature and time for sample equilibrati...

Journal: :Journal of AOAC International 2000
S Abrantes T C Dos Santos G Simões S Abrantes

A headspace gas chromatographic (GC) method was developed to determine 1,3-butadiene (1,3-BD) in simulated saliva in contact with chewing gum. The calibration graph was linear, and the limit of detection was 0.004 mg/L, which is well below the migration limit for this substance. The headspace GC method provides rapid and reliable analysis for monitoring 1,3-BD migration from chewing gum into si...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد شاهرود - دانشکده علوم پایه 1393

در این پژوهش به تجزیه شیمیایی و بررسی اسانس حاصل از دو گیاه ferula foetida و prangos uloptera پرداخته شده است . دو گیاه پس از جمع آوری به اجزاء برگ ، گل و ساقه تفکیک و در سایه تحت جریان ملایم هوا خشک شدند سپس با استفاده از دو روش تقطیر با آب و headspace از نمونه های گیاهی اسانس گرفته شد . همچنین اثر آنتی اکسیدانی حاصل از عصاره متانولی ferula foetida نیز مورد بررسی قرار گرفت . ترکیبات عمده و ...

2017
Bridget Bassilios Nicolas Telford Debra Rickwood Matthew J Spittal Jane Pirkis

OBJECTIVE Access to Allied Psychological Services (ATAPS) was introduced in 2001 by the Australian Government to provide evidence-based psychological interventions for people with high prevalence disorders. headspace, Australia's National Youth Mental Health Foundation, was established in 2006 to promote and facilitate improvements in the mental health, social wellbeing and economic participati...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید