Statement of Work.pdf

Statement of Work

Description of Supplies/Quantity Required:

• A high-performance liquid chromatography (HPLC) system ×1

Background and Scope:

• The USDA–ARS uses this HPLC system to collect invaluable data on the chemical composition of fruits and vegetables with a focus on organic acids and sugars in cranberries. Currently, titratable acidity and Brix are widely accepted as measures of total organic acids and total sugars in cranberries, respectively, while these values do not provide any detailed information on the chemical composition. Previously reported HPLC studies on the chemical composition of cranberries have revealed that the major organic acids are citric, malic, quinic, shikimic, succinic, and tartaric acids and that the major sugars are fructose, glucose, and sucrose. In the HPLC-based analysis of organic acids, a dilute sulfuric acid solution is typically used as the elution buffer or mobile phase;

however, the same elution buffer cannot be used for the HPLC-based analysis of sugars because sucrose degrades in the elution buffer due to the effect of the sulfuric acid. Furthermore, organic acids and sugars need to be detected using ultraviolet (UV) and refractive index (RI) detectors, respectively, because the peaks of organic acids and those of sugars overlap or diminish if only a single type of detectors is used. This HPLC system must consist of one flow path, a separation column(s) for organic acids, a separation column(s) for sugars, a valve or switching mechanism capable of switching between the two different types of separation columns and elution buffers without disconnecting/connecting the columns, a UV detector, and an RI detector. The data collected using this HPLC system will allow us to determine the organic acid/ sugar compositions of cranberry fruits and products and will give us a better understanding of the impact of growing/processing conditions on the quality of cranberry fruits/products.

Technical Requirements/Specifications:

• An HPLC system o The system must be a modular system. Each module must be exchangeable without uninstalling the system.

o The base module must include a solvent rack, tubing for one flow path, and a valve or switching mechanism capable of switching between two different types of separation columns and elution buffers without disconnecting/connecting the columns.

o A quaternary pump must be included. The pump must have an operational flow rate of 0.001–10 mL/min and an integrated vacuum degassing function.

o A split-loop sampler must be included. The sampler must have an injection volume range of 1–100 µL and a 100 µL sample loop.

Connecting/disconnecting a sample loop must be possible without using tools.

o The system must have an ability to damp the impact of the injection shock to improve retention time precision.

o A guard column(s) appropriate for the use with two different types of separation columns must be included.

o A separation column(s) capable of separating citric, malic, quinic, shikimic, succinic, and tartaric acids must be included. The column(s) must use a dilute sulfuric acid solution as the elution buffer.

o A separation column(s) capable of separating fructose, glucose, and sucrose must be included. The column(s) must use water as the elution buffer.

o Connecting/disconnecting a column must be possible without using tools.

o A column heater(s) must be included. The column heater(s) must be capable of housing all separation columns and maintaining a column temperature prespecified for each separation column. If the prespecified column temperature of one type of the separation columns exceeds the temperature tolerance of the other type of the separation columns, two individual column heaters for each type of the separation columns must be provided.

o A variable wavelength detector must be included. The detector must be functional in a wavelength range of 190–750 nm.

o A refractive index detector must be included. The detector must have an integrated temperature control function.

o A workstation and software to monitor the system, solvent, and waste statuses, acquire data, and analyze the obtained data must be included.

o The voltage must be 110–120 V.

• Installation

• Training

Data Requirements:

• A chromatogram that shows clear separation of organic acids, including citric, malic, quinic, shikimic, succinic, and tartaric acids, must be provided. These organic acids must be separated using the separation column(s) and a dilute sulfuric acid solution as the elution buffer and detected using the UV detector.

• A chromatogram that shows clear separation of sugars, including fructose, glucose, and sucrose, must be provided. These sugars must be separated using the separation column(s) and water as the elution buffer and detected using the RI detector.

Deliverables/Schedule:

Delivery to Shinya Ikeda of the USDA–ARS Vegetable Crops Research Unit (VCRU) located at 1605 Linden Drive, Madison, WI 53706 by 4/30/2024 or as negotiated.

Travel:

To USDA-ARS VCRU located at 1605 Linden Drive, Madison, WI 53706 for installation and training.