January 5, 2022 Longchang Chemical
  1. Nuclear magnetic resonance spectrometer:
    (1) The purity of the sample submitted for inspection should generally be >95%, free of iron filings, dust, filter paper wool and other impurities. Generally, the amount of sample required for organic matter: 1H spectrum>5mg, 13C spectrum>15mg, the amount of sample required for polymers should be increased appropriately.
    (2) For liquid sample analysis, the sample is required to have good solubility in a certain deuterated solvent, and the solvent should be selected first. The commonly available deuterated solvents are chloroform, heavy water, methanol, acetone, DMSO, benzene, o-dichlorobenzene, acetonitrile, pyridine, acetic acid, and trifluoroacetic acid.
    (3) Provide the possible structure or source of the sample. If there are special requirements (such as detection temperature, spectrum width, etc.).
  2. Infrared spectrometer:
    (1) The sample must be purified in advance to ensure sufficient purity;
    (2) The sample must be dewatered and dried in advance to avoid damage to the instrument and at the same time to avoid the interference of water peaks on the sample spectrum;
    (3) For samples that are prone to deliquescent, please prepare your own desiccator for storage;
    (4) For samples that are volatile, sublimable, and unstable to heat, use a container with a sealed lid or stopper and close it tightly;
    (5) For toxic and corrosive samples, they must be packed in sealed containers.
  3. Organic mass spectrometer:
    It is suitable for analyzing liquid and solid organic compound samples with a relative molecular mass of 50 ~ 2000u. The sample should be as pure as a single component.
  4. Gas chromatography-mass spectrometer:
    The sample entering the gas chromatography furnace must be completely vaporized within the working temperature range of the chromatographic column.
  5. Liquid chromatography-mass spectrometer:
    (1) Flammable, explosive, toxic, and corrosive samples must be marked.
    (2) In order to ensure the accuracy and reliability of the analysis results, the samples are required to be completely dissolved without mechanical impurities.
    (3) Provide the structural formula, molecular weight or functional groups of the sample as much as possible in order to select the ionization method; (4) When liquid chromatography-mass spectrometry is used, all buffer systems shall use volatile buffers, such as acetic acid, ammonium acetate, hydrogen It is formulated with tetrabutylammonium oxide, etc.
  6. Time of flight mass spectrometer:
    (1) Specimen type, composition and sample size
    The instrument is good at measuring peptides and proteins, as well as other biological macromolecules such as polysaccharides, nucleic acids and high molecular polymers, synthetic oligomers, and some organic substances with relatively small molecular weights, such as C60 or C60 grafts. The sample to be tested can be a single component or multi-component, but the more the sample components, the more complex the spectrum and the more difficult the spectrum analysis; if there is mutual inhibition between the components during the ionization process , It may not be guaranteed that each component has peaks. The sample volume for routine determination is about 1-10 picomoles/microliter.
    (2) The solubility of the sample
    The sample to be tested must be soluble in a suitable solvent, preferably an undissolved solid or pure liquid.
    (3) Purity
    In order to obtain high-quality mass spectra, peptide and protein samples should avoid sodium chloride, calcium Goal In order to obtain high-quality mass spectra, peptide and protein samples should avoid sodium chloride, calcium chloride, potassium hydrogen phosphate, dimethyl sulfoxide, urea, glycerol, trinitrotoluene, tween, dodecyl sulfate Chemical substances such as sodium. If the test sample cannot avoid the use of the above reagents in the pretreatment process, the sample must be purified by dialysis and high performance liquid chromatography. Water, ammonium formate, ammonium acetate, ammonium bicarbonate, acetonitrile, trifluoroacetic acid, etc. are all suitable reagents for purifying samples. The salt in the sample can be removed by ion exchange method. After the protein sample is purified, it should be lyophilized as much as possible.
  7. Ultraviolet-visible absorption spectrometer:
    (1) The concentration of the sample solution must be appropriate, and it must be clear and transparent, and there must be no bubbles or suspended substances;
    (2) The amount of solid samples> 0.2 g, and the amount of liquid samples> 2 ml.
  8. Gas chromatograph:
    The samples that can be directly analyzed should be volatile and thermally stable. The boiling point is generally not more than 300 ℃. If the sample cannot be injected directly, pre-treatment is required.
  9. Liquid chromatograph:
    The sample should be dry, and it is best to provide the structure of the component to be tested; for complex samples, provide as much as possible what other components may be in the sample.
  1. Element analyzer:
    (1) The sample must be a uniform solid particle or liquid that does not contain adsorbed water and has been purified. If the sample is not pure (contains adsorbed water, organic solvent, inorganic salt or other impurities), it will affect the analysis result, causing the test value to be inconsistent with the calculated value;
    (3) The sample should have sufficient amount to meet the linearity and sensitivity of the method and instrument.
  2. Ion chromatograph:
    The sample can be soluble in water, or dilute acid or alkali, and the acid or alkali used should not contain the ions to be tested. For compounds that contain the element to be tested but exist in a non-ionic state in water, acid, and alkali solutions, corresponding sample pretreatment is required.
  3. Plasma atomic emission spectrometer:
    ①List as far as possible the main components, impurity components and their (estimated) content; what is the lowest (estimated) content of the elements to be tested? For the solution, indicate the medium composition (the type of solvent, acid and base and its (estimated) content), whether it contains fluorine (F-) or not? Because fluorine (F-) will seriously corrode the atomizer!
    ②The solid sample should be made into a solution that does not contain any organic matter, the final acidity is controlled to 1 mol, and the sample size: 5-50 ml. If it contains suspended solids or precipitates, be sure to filter.
    ③The sample is required to be processed into a solution.
  4. Atomic fluorescence spectrometer:
    (1) General requirements for sample analysis
    The objects analyzed by the atomic fluorescence spectrometer are arsenic (As), selenium (Se), germanium (Ge), tellurium (Te), etc. and mercury (Hg) atoms that exist in ion states. The sample must be an aqueous solution or soluble in acid.
    (2) Solid samples
    ①Inorganic solid sample, the sample maintains proper acidity after simple dissolution.
    Detect arsenic (As), selenium (Se), tellurium (Te), mercury (Hg), the medium is hydrochloric acid (5%, v/v);
    Detect germanium (Ge), the medium is sulfuric acid (5%, v/v);
    For mercury (Hg) detection, the medium can also be nitric acid (5%, v/v), and the detection (As) medium can also be sulfuric acid (2%, v/v).
    Since copper, silver, gold, platinum and other metals have greater interference with the elements to be measured, arsenic, selenium, tellurium, and mercury in these types of alloy samples should not be determined by this instrument.
    ②Organic or biological solid samples
    The sample is nitrated into a solution and maintains proper acidity. The acidity of the medium is the same as that of the inorganic sample.
    (3) Limit requirements for the elements to be tested in the sample
    Determined by the sensitivity of the instrument and the analysis method, the upper and lower limits of the element to be measured in the sample are 0.05 μg/g ~ 500 μg/g. The detection of samples outside this content range with this instrument will not guarantee the accuracy and reliability of the detection results.
    (4) Sample size
    For each element to be detected, the amount of solid sample is not less than 2 g, the amount of liquid sample is not less than 20 mL, and the water sample is not less than 100 mL.
  5. Differential scanning calorimeter:
    Solid samples will not decompose or sublime within the temperature range tested, and no volatile matter will be produced. Sample size: no less than 20mg for inorganic or organic materials and no less than 5mg for drugs in a single test.
  6. Thermogravimetric analyzer:
    Sample size: not less than 30mg. Indicate the detection temperature range, experimental atmosphere (air, N2 or Ar), heating rate, gas flow rate (if there are special requirements).

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