外国一级黄色毛片,久久电影精品久久99久久,欧美桃色视频,狠狠色成人综合网图片区,在线观看亚洲,久久天天综合,亚洲一区二区综合

Conditions for Making a Reference Standard Return

• The product(s) must be unopened and in its original packaging.

• The product(s) must be stored appropriately, as indicated on the certificate of analysis.

• In the case the return is being requested due to an error on Herbest’s behalf, we will investigate the root cause of the error. If it is deemed a Herbest error, the product(s) can be returned regardless if it meets the conditions above or not.

Restocking and Shipping Fees

• All returns are subject to a 20% restocking fee (unless deemed a Herbest error after investigation).

• Shipping fees will not be refunded unless the cause for the return was found to be an error on Herbest’s part.

Return Instructions

1.  In order to initiate a return, please contact your Herbest representative and provide the       following information:

• The invoice document number for purchase

• The lot number(s) for the product(s) intended to be returned

• Reason for return of the product(s)

2.  After receiving the information listed above, your herbest representative will generate a  return number  for you to authorize the return.

3. Once the return number is received, please ship the product(s) with the return number (RTN) referenced on the package. Ensure the product(s) is/are appropriately packaged and stored (i.e. -20oC stored items need to be shipped overnight with an icepack, -80oC items with dry ice). The shipment will be made out to the following address:

Baoji Herbest Bio-Tech Co.,Ltd

Attn:[herbest representative]

BaoTao Road Baoji City Shannxi provience China (zip: 721013)

Tel:+86-917-8888998

4. Once the product(s) is/are received and inspected, your representative will issue a return (RTN) document receipt. This document will reflect the funds credited back to you for return of the product(s), minus any applicable restocking or shipping fees. Purchases made via prepayment or NET 30 will have a credit memo for the balance added to their account.

Herbest supplies a wide range of phytochemical reference standards to highly specialized and very rare phytochemicals available in extremely small quantities in nature. Our specialtis making all of these products available to the industry with extensive testing and characterization data on each.   Herbest committed to providing our customers with cost effective, high quality reference  tandards. We strive to provide that influence how long it will take to fill any individual order and we hope this information will assist you in understanding our production process and lead time estimates.

Production Phase 1 :Starting Materials

The first phase in our production process is to acquire the necessary starting materials. In the case that the compound will be isolated directly from plant material, we must first acquire the relevant biomass. Availability of suitable biomass can vary widely and might require waiting for the next harvest time to maximize the level of the target phytochemical. Growing and harvest conditions can dramatically affect the phytochemical content and in extreme cases, normally prominent target compounds might be missing entirely from a particular harvest. This certainly can complicate the production process. All biomass materials have to be verified for compliance with Herbest quality requirements. Compounds 

produced synthetically also require properly qualified starting materials. In this case, the commercial availability of the starting materials directly affects our ability to begin the production process.

Production Phase 2: Production of Target Compound

Once all the starting materials are received and qualified, we can begin with the production of the target compound. Depending on production prioritization, some materials may have to wait in the production queue before work begins. Both isolation and synthesis productions are typically multistep processes and can take from just a few days to several weeks to complete the whole process. Usually production steps proceed smoothly but sometimes unanticipated technical challenges can arise.  

Production Phase 3: Quality Testing and Verification

In this phase, the isolated or synthesized materials are tested and verified. The results must meet the final identity, purity, and quality requirements for the desired product. The data package from this characterization testing is then used to generate the product certificate of analysis (C of A) appropriate to the product grade. The C of A then undergoes a formal review by the Quality Assurance group that operates independently of the chemists performing the tests and preparing the documentation. Oncethe C of A is completed, the material can then go into stock and orders are filled. Usually quality testing and verification is a smooth process but in some cases, material that was promising during Phase 2, will fail final requirements during Phase 3 testing in which case, the process must start over.

Herbest takes pride in providing its customers with the highest quality natural product reference standards available to the industry.Please contact your Technical Sales Representative with any additional questions you may have.

Herbest reference standards are supplied in the powder, crystal, liquid, or oily form. The reference standards may also be supplied in various containment forms including screw top vials, crimp top vials, or sealed ampules (depending on the best form of enclosure determined by Herbest). This can present a recovery challenge when the material clings to the insides of the sample bottle/vial. Proper handling is especially important with small amounts where a greater percentage of the sample may be clinging to the sides of the bottle, screw cap or sto per. Please note that Herbest  does not recommend scraping the vial because sample recovery will be quite low. The following procedure for sample handling will allow for the greatest recoveries and proper dilution. Please note: Oily or liquid standards can be difficult to see and the bottle may appear empty. Examples of such oily standards are: Gingerol, Pinane, Shogaol,Rosin and Bakuchiol.

Proper Standard Material Recovery and Dilution Procedure:

1. Use a 5 decimal place (0.00001g) analytical balance for weighing.

2. Weigh the full sample bottle and vial cap.

3. Record the exact weight of the full bottle and cap/stopper, in your laboratory notebook.

4. Remove the screw top of the vial and add about 1mL of the appropriate solvent to the sample bottle and immediately replace the cap/stopper. If the bottle/vial has a crimp top, draw 1ml of the appropriate solvent into a clean syringe (with a rigid needle tip) and pierce the crimp top septum and expel the 1ml of solvent into the vial.

5. Shake the bottle/vial multiple times over 5 minutes and allow the standard to completely dissolve.

6. Open the screw/crimp top vial and pipette or pour the dissolved standard from the bottle into a volumetric flask (Crimp top vial will need a crimp top remover tool).

7. Use an appropriately sized volumetric flask for the sample dilution.

8. Rinse the bottle/vial and cap/stopper each into the volumetric flask three times.

9. Completely dry the empty bottle and cap/stopper under nitrogen flow.

10. Weigh the, now empty, dried bottle and cap/stopper and record the weight in your laboratory notebook. 

11. Partially fill the volumetric flask with the chosen solvent and mix thoroughly.

12. Then dilute to the mark and mix again by inverting several times.

13. Calculate the total weight of standard removed from the bottle/vial by subtracting the dry weight from the original weight.

14. Calculate the concentration of the diluted standard by dividing the calculated standard weight (from step above) by the volume of the volumetric flask.

15. Consider portioning off your diluted standard into smaller bottles for later use and to prevent contamination of your standard solution.

16. Ideally, store the reference standard solution in a cool, dry place out of light per recommended storage conditions found on the Certificate of Analysis and/or label.

please contact Herbest with any further questions about proper sample handling specific to your use.

Herbest is pleased to offer a wide range of reference standards in our phytochemical catalog. All materials listed are supplied either neat or in solution and sold by either a weight or volume quantity. Sometimes our clients have questions about how much product is in each bottle or ampoule. This FAQ should help to address such questions.

Herbest overfills each unit of product by up to 0.2 mg. This typically means that a 5mg unit may contain between 5.0 and 5.2mg of material; a 10mg unit contains between 10.0 and 10.2mg of material. Products sold by volume are overfilled by 0.1ml.

The use of accurate weight measurements and fully characterized Primary grade reference standards is crucial for proper quantitative analysis. A five place balance (measuring accurately to 0.00005mg) is required for use in quantitative work.

Herbest recommends that a “weigh by difference” technique be used when preparing your reference standard solutions for use in the laboratory. Especially when dealing with oily, sticky, fluffy, or static prone compounds, improper handling can result in large losses of material between the original packaging and the prepared solution in your laboratory.Because of potential material loss in transferring by the end user, Herbest does not supply an exact weight value for each unit of reference standard. Even if an exact weight was supplied, the end user must accurately weigh the amount of product that goes into their standard preparation as this minimizes analytical error.

For special projects, Herbest can supply exact weights per vial when requested by our clients. An additional fee may apply in such cases. Please contact your herbest sales representative for more information if this service would be useful for you.

Herbest packages all items carefully to minimize any product loss. However, sometimes shipping conditions beyond our control can cause leakage or an otherwise reduced quantity of material. If you suspect that your order contains less material than it should, please first follow the weighing protocol as detailed in  Herbest Recovery and Dilution Procedures. If after using this protocol, you cannot verify the correct quantity, please contact your Herbest sales representative with the weight measurements and any photos showing bottle leakage that might help us in trouble shooting the issue.