使用X射線能量色散熒光光譜儀(XRF Analyzer)的測試程序和步驟
1 光譜儀準備
a) 按照儀器的工作說明書給儀器通電,加熱設備,按廠家說明書對儀器進行穩定。
b) 確保測試穩定,并按照制造商的說明使檢測器穩定
2 校準
a) 根據儀器用戶手冊的說明,按照第 7 節的說明選擇參考樣品作為校準樣品。樣品中的元素
濃度應該不一樣。如果校準覆蓋的元素多,濃度范圍大,則需要大量的校準樣品。
由于以下原因,校準樣品的數量有所減少:
— 用基本參數法校準(元素小于標準)
— 使用基本參數方法校準(使用具有相似元素的標準)
— 使用基本參數方法分析加經驗校準
b) 分析方法校準考慮了光譜的干擾、基體效應等影響,這些都會影響光譜中熒光散射的強度
決心的程度。這些效果的列表可以在本章的附件中找到。
c) 為保證各測量元素的分析性能合格,需選擇合適的激發參數,使儀器處于好的狀態
測量條件。這些條件是儀器需要的。通常,此信息可以在分析師的說明手冊中找到
d) 作為一般準則,推薦方法的用戶知道,相互元素譜的干擾和樣品間基質的變化將充分影響
對每個分析物結果的準確度、精密度和檢測限。例如純聚乙烯中Cd的檢出限可達
至 15mg/Kg,但當存在 10% 溴化合物和/或 2% 銻時,無法達到檢測限
3 檢測器性能檢查
無論設備是否滿足要求的性能標準,都需要通過測量認證參考材料或相關參考樣品
決定。樣品中所含元素的濃度不得大于測試元素篩選限值的3-5倍(見表3)。按參考樣本
產品得到的結果必須在樣品測試誤差的允許范圍內。當設備用于分析未知材料時,制造商應提供
標準操作程序 (SOP) 和適當的參考樣本。推薦的方法應該保證操作者可以獲得高質量的定量分析結果。
4 測試樣品的放置
a) 如果待測樣品可以放置在臺式X射線熒光光譜儀內部的樣品室中,并且待測樣品被正確測量
位置,可以進行相應的測試。如果待測樣品不適合放置在樣品室中,則必須將其切割以適合
尺寸易于測量。為了使測試結果有效,必須滿足儀器關于樣品厚度和質量的要求。
因為非常小的或薄的樣品可能不符合這個條件。在這種情況下,這樣的小樣本(如蝸牛)
線釘)放置在樣品杯中,然后進行分析。同樣,相似的薄樣品應堆疊在一起,以便
足以達到有效分析的最小樣品厚度限制。一個總的原則是所有樣本必須*
蓋住光譜儀的測量窗口。對于聚合物和輕合金,例如 Al、Mg 和 Ti,其厚度至少應為 5mm。
液體的最小厚度為 15 毫米,而其他合金的厚度約為 1 毫米。但由于設備的個體差異,
所需的樣本量也不同。光譜儀的操作人員應參考設備手冊或遵循制造商的要求。
制備樣品的尺寸/質量/厚度。
b) 如果在便攜式 XRF 光譜儀上進行測試,必須注意光譜儀的測量窗口應為
測試樣品相對并直接接觸。小樣品或非常薄的樣品應按照上述 a) 中提到的方法進行操作。當然
然后使用附件(如果有)進行分析,讓操作員可以測量樣品杯中的樣品。關于最
小樣品的尺寸/質量/厚度規定也適用于便攜式分析。
c) 如果樣品是液體、粉末或球形,或者只是一個小樣品,則需要
在樣品杯中測量薄膜。處理此窗膜時,請注意不要
觸摸其表面以避免弄臟它
5 篩選測試
a) 按規定時間進行測試。
b) 顯示和記錄分析結果。
6 結果分析
各種類型的 XRF 光度計單獨使用,分析方法允許用戶將樣品分為以下三類之一:
a)“合格”——如果所有元素的定量分析結果均小于表2所列的下限,則該樣品為合格。
b) “不合格”——如果全部高于表 2 所列的上限,則樣品檢測為不合格。
c) “未定”——如果 Hg、Pb 或 Cd 任何元素的定量分析結果在中間區域
或元素Br和Cr的結果高于表2所列的上限,分析結果未定。 也得進步一步研究。 本次測試“未定”
The test procedure and steps of using X-ray energy dispersive fluorescence spectrometer (XRF Analyzer)
1 Spectrometer preparation
a) Power on the instrument according to the working instructions of the instrument, heat the equipment, and stabilize the instrument according to the manufacturer's instructions.
b) Ensure that the test is stable, and make the detector stable according to the manufacturer's instructions
2 calibration
a) According to the instructions in the instrument user manual, follow the description in section 7 to select the reference sample as the calibration sample. Of the elements in the sample
The concentration must be different. If the calibration covers a lot of elements and the concentration range is large, a lot of calibration samples are needed.
The number of calibration samples has decreased due to the following reasons:
— Calibrate with the basic parameter method (the elements are less than the standard)
— Calibrate with the basic parameter method (using a standard with similar elements)
— Use basic parameter method analysis plus experience to calibrate
b) The analysis method calibration takes into account the interference of the spectrum, matrix effects and other effects, which will affect the intensity of fluorescence scattering in the spectrum
Degree of determination. A list of these effects can be found in the attachment to this chapter.
c) In order to ensure the qualified analytical performance of each measurement element, it is necessary to select the appropriate excitation parameters to make the instrument at the best
Measurement conditions. These conditions are unique to the instrument. Typically, this information can be found in the analyst’s instruction manual
d) As a general guideline, users of the recommended method know that the interference of mutual element spectra and changes in the matrix between samples will fully affect
To the accuracy, precision and minimum detection limit of each analyte result. For example, the detection limit of Cd in pure polyethylene can reach
To 15mg/Kg, but when 10% bromine compound and/or 2% antimony are present, the detection limit cannot be reached
3 Detector performance check
Regardless of whether the equipment meets the required performance standards, it needs to pass measurement certification reference materials or related reference samples to
determine. The concentration of the element contained in the sample must not be greater than 3-5 times the screening limit of the test element (see Table 3). By reference sample
The result obtained by the product must be within the allowable range of the sample test error. When the equipment is used to analyze unknown materials, the manufacturer should provide
A standard operating procedure (SOP) and an appropriate reference sample. The recommended method should ensure that the operator can get high quality
Quantitative analysis results.
4 Placement of test samples
a) If the sample to be tested can be placed in the sample chamber inside the desktop X-ray fluorescence spectrometer, and the sample to be tested is properly measured
Location, you can perform the corresponding test. If the sample to be tested is not suitable for being placed in the sample chamber, it must be cut to fit
The size is easy to measure. In order for the test results to be valid, the minimum requirements of the instrument regarding sample thickness and quality must be met.
Because very small or thin samples may not meet this condition. In this case, such small samples (such as snails)
Wire nails) are placed in a sample cup, and then analyzed. Similarly, similar thin samples should be stacked together so that
Enough to reach the minimum sample thickness limit for effective analysis. A general principle is that all samples must be completely
Cover the measurement window of the spectrometer. For polymers and light alloys such as Al, Mg and Ti, it should be at least 5mm thick.
The minimum thickness for liquids is 15mm, while for other alloys the thickness is about 1mm. However, due to individual differences in equipment,
The required sample size is also different. The operator of the spectrometer should refer to the equipment manual or follow the minimum required by the manufacturer.
Size/mass/thickness to prepare samples.
b) If the test is performed on a portable XRF spectrometer, it must be noted that the measurement window of the spectrometer should be
The test sample is opposite and in direct contact. Small or very thin samples should be operated in accordance with the method mentioned in a) above. Of course
Then use an accessory (if available) for analysis, allowing the operator to measure the sample in the sample cup. About the most
The size/quality/thickness regulations for small samples also apply to portable analysis.
c) If the sample is liquid, powder or spherical, or just a small sample, it needs to be
The film is measured in the sample cup. When handling this window film, be careful not to touch its surface to avoid staining it
5 screening test
a) Test according to the stipulated time.
b) Display and record analysis results.
6 Result analysis
Various types of XRF photometers are used individually, and the analysis method allows users to classify samples into one of the following three categories:
a) "Pass"-if the results of quantitative analysis of all elements are all less than the lower limit listed in Table 2, the sample has been tested Is qualified.
b) "Unqualified"-If all of them are higher than the high limit listed in Table 2, the sample will be unqualified after testing.
c) "Undecided"-if the result of quantitative analysis of any element of Hg, Pb or Cd is in the middle area
Or the results of the elements Br and Cr are higher than the upper limit listed in Table 2, and the analysis result is undecided. Also have to make progress
One-step research. This test is "undecided"
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