식물 조직에서 유기산을 정량화하는 모세관 전기 영동을 사용하여 : 테스트 케이스 검사<em> 커피 나무 아라비카</em> 씨앗
Summary
이 문서에서는 검색 및 무료 띠 모세관 전기 영동을 이용하여 식물 재료에서 유기산 정량하는 방법을 제시한다. 커피 종자 유기산 농도에서 발효 차의 효과를 결정하는 이러한 방법의 잠재적 인 애플리케이션의 일례가 제공된다.
Abstract
카르 복실 산, 하나 이상의 단말 카르복실기 (COOH) 작용기를 함유하는 유기산이다. 짧은 체인 카르 복실 산 (SCCAs, 3 ~ 6 탄소를 포함하는 카르 복실 산) 등의 말 산염과 구연산 등이, 그들은 세포 호흡에서 기능과 세포 건강의 지표 역할을 할 수있는 많은 생물 시스템의 적절한 기능에 중요하다. 식품에서의 유기산 함유량은 신 또는 "산"맛 결과 증가 SCCA 수준의 맛에 큰 영향을 가질 수있다. 이 때문에 유기산 농도의 신속한 분석을위한 방법은 음식 및 음료 산업에서 특히 중요하다. 그러나, 불행히도 SCCA 정량 방법에 사용 가장 비싼 크로마토 그래피 및 / 또는 질량 분광 분석을 하였다 위험한 시약과 시료의 유도체를 요구하는 시간 소모적 인 프로토콜에 의존한다. 이 방법은 조직의 검출과 정량을위한 다른 방법의 자세한 사항식물 재료 및 무료 띠 모세관 전기 영동 (CZE)를 이용하여 음식 샘플로부터 anic 산은 때때로 단순히 모세관 전기 영동 (CE) 라 함. CZE 검출의 하한 (0.005 ㎎ / ㎖)로 SCCAs을 측정하기위한 비용 효율적인 방법을 제공한다. 이 문서에서는 식물 샘플에서 SCCAs의 추출 및 정량을 자세히 설명합니다. 제공된 방법은 커피 콩 SCCAs 측정에 초점을 맞추고 있지만, 제공되는 방법은 여러 식물성 식품 재료에 적용될 수있다.
Introduction
Carboxylic acids are organic compounds containing one or more terminal carboxyl functional groups, each attached to an R-group containing one or more carbons (R-C[O]OH). Short chain, low molecular weight carboxylic acids (short chain carboxylic acids, SCCAs) containing between one and six carbons, are essential components of cellular respiration, and function in several biochemical pathways necessary for cell growth and development. SCCAs play critical roles in cellular metabolism1, cell signaling2, and organismal responses to the environment (such as antibiosis3). Because of this, SCCAs can serve as useful indicators of disruptions to cellular metabolism, plant stress responses4,5, and fruit quality6,7. To date, SCCAs have been quantified primarily through chromatographic techniques such as high performance liquid chromatography (HPLC) or gas chromatography-mass spectroscopy (GC-MS). While these methods, are capable of achieving very low limits of detection, they can be expensive, require the derivatization of target SCCAs using caustic and/or toxic reagents, and include lengthy separation runs on the GC or HPLC. Because of this, interest in the use of free zonal capillary electrophoresis (CZE), which does not require sample derivatization, to quantify organic acids has steadily increased8.
Free zonal capillary electrophoresis (CZE) is a chromatographic separation methodology that, due to its high number of theoretical plates, speed, and relative ease-of-use, is increasingly replacing both GC-MS and high-pressure liquid chromatography as an analytical method for the quantification (particularly for quality control purposes) of anions, cations, amino acids, carbohydrates, and short chain carboxylic acids (SCCAs)8,9,10. CZE-based separation of small molecules, including SCCAs, is based two primary principles: the electrophoretic movement of charged ions in an electrical field established across the buffer filling the capillary; and the electro-osmotic movement of the entire buffer system from one end of the capillary to the other, generally towards the negative electrode. In this system, small molecules move towards the negative electrode at varying speeds, with the speed of each molecule determined by the ratio of the net charge of the molecule to the molecular mass. As the movement of each individual molecule in this system is dependent on the charge state of the molecule and the overall rate of electro-osmotic flow (which is itself based on the ion content of the buffer used to fill the capillary), the buffer pH and ionic composition heavily impact the degree to which molecules can be efficiently separated using CZE. Because of this, SCCAs, with their relatively high charge-to-mass ratios, are ideal targets for CZE-based separation. Metabolites separated using CZE can be detected using a variety of methods, including UV absorbance, spectral absorbance (which is generally performed using a photo-diode array [PDA]), and/or mass spectroscopy (CE-MS or CE-MS/MS)8. The diversity of separation and detection methods provided by CZE makes it an extremely flexible and adaptable technique. Because of this, CZE has been increasingly applied as a standard method of analysis in the areas of food safety and quality11,12, pharmaceutical research13, and environmental monitoring13,14.
Capillary electrophoresis has been used to detect and quantify short chain carboxylic acids for nearly two decades13. The resolving power (particularly for small, charged molecules), short run time, and low per sample cost of CZE analyses make CZE an ideal technique for the separation and quantification of SCCAs13. This method presents a protocol to utilize CZE to measure the concentration of organic acids from plant tissues. Example data was generated through the successful implementation of this protocol to measure the change in organic acid levels in coffee seeds following a secondary fermentation treatment. The protocol details the critical steps and common errors of CZE-based separation of SCCAs, and discusses the means by which this protocol can be successfully applied to quantify SCCAs in additional plant tissues.
Protocol
Representative Results
Discussion
임의의 분석 기법으로 크게 발생되는 데이터의 품질과 신뢰성에 영향을 미칠 수있는 여러 가지 중요한 요소가있다. 첫째, 냉동 / 해동 사이클을 최소화하여, 샘플을 효율적으로 처리하는 것이 중요하다. 반복 된 동결 융해 처리 또는 분석 전에 샘플의 화학 성분을 손상시킬 수있다. 둘째, 일관되고 균일 모든 샘플이 프로토콜의 단계를 적용하는 것이 중요하다. 일관성 샘플 준비 및 처리 기술에서 …
Disclosures
The authors have nothing to disclose.
Acknowledgements
The authors would like to acknowledge the financial support of this project by The J.M. Smucker company.
Materials
| Ceramic Moarter and Pestle | Coorstek | 60310 | |
| Beckman Coulter P/ACE MDQ CE system | Beckman Coulter | Various | |
| Glass sample vials | Fisher Inc. | 033917D | |
| 1.5 ml microcentrifuge tubes | Fisher Inc. | 02-681-5 | |
| LC/MS grade water | Fisher Inc. | W6-1 | Milli-Q water (18.2 MΩ.cm) is also acceptable |
| 15 ml glass tube/ Teflon lined cap | Fisher Inc. | 14-93331A | |
| Parafilm M | Fisher Inc. | 13-374-12 | |
| CElixirOA detection Kit pH 5.4 | MicroSolv | 06100-5.4 | |
| BD Safety-Lok syringes | Fisher Inc. | 14-829-32 | |
| 17 mm Target Syringe filter, PTFE | Fisher Inc. | 3377154 | |
| 32 Karat, V. 8.0 control software | Beckman Coulter | 285512 | |
| capillary electrophoresis (CE) sample vials | Beckman Coulter | 144980 | |
| caps for CE vials | Beckman Coulter | 144648 | |
| Liquid Nitrogen | N/A | N/A | Liquid nitrogen is available from most facilities services |
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