A specific early eluting peak in Bio-Rad Variant II cation-exchange high-performance liquid chromatography (CE-HPLC) for the screening of alpha-thalassaemia in a Chinese population.

The early eluting peaks in the first minute of cation-exchange high-performance liquid chromatography (CE-HPLC) are often not analysed in haemoglobin pattern studies, except for haemoglobin (Hb) Bart's and Hb H peaks. In this study, we described the presence of a specific α-thalassaemia early eluting peak (αEEP) at the retention time of 0.24 min generated by Variant II CE-HPLC (ß-Thalassaemia Short Program; Bio-Rad Laboratories). We have evaluated the utility of αEEP for the screening of α-thalassaemia trait in our local Chinese population in comparison to the Hb H inclusion body test. A total of 303 blood samples presenting with microcytosis were sent for haemoglobin pattern study and were analysed for the presence or absence of αEEP and Hb H inclusions. Twenty cases with a normal mean corpuscular volume were assessed as a control. Discordant results between the αEEP and the Hb H inclusion test were reviewed with the α-globin genotyping test performed. The concordance rate of the αEEP and the Hb H inclusion body test was 96.0% (κ=0.921, p<0.001). Eight of 303 cases (2.6%) were initially negative for the Hb H inclusion test but positive for the αEEP. All eight cases were found to have occasional Hb H inclusion bodies upon review. Four of 303 cases (1.3%) were negative for the αEEP but positive for the Hb H inclusion test. Of these four cases, two (50%) showed heterozygous Southeast Asian (SEA) type deletion, one (25%) showed Hb Quong Sze mutation, and one (25%) showed no mutation detected upon molecular testing. All the Hb E trait cases with no Hb H inclusions and the negative control group showed the absence of the αEEP. The sensitivity and specificity of αEEP for detecting SEA deletion were 93.8% and 100% respectively, which is superior to the Hb H inclusion test (sensitivity 81.3%, specificity 95.2%). The αEEP is found to be a more sensitive method than the Hb H inclusion body test in the screening of α-thalassaemia trait in our Chinese population, in which SEA type deletion is prevalent. Further study is needed to explore the utility of the αEEP in the screening of α-thalassaemia traits in other populations. The exact nature of the αEEP is yet to be defined.

Advances in rapid detection of SARS-CoV-2 by mass spectrometry.

COVID-19 has already been lasting for more than two years and it has been severely affecting the whole world. Still, detection of SARS-CoV-2 remains the frontline approach to combat the pandemic, and the reverse transcription polymerase chain reaction (RT-PCR)-based method is the well recognized detection method for the enormous analytical demands. However, the RT-PCR method typically takes a relatively long time, and can produce false positive and false negative results. Mass spectrometry (MS) is a very commonly used technique with extraordinary sensitivity, specificity and speed, and can produce qualitative and quantitative information of various analytes, which cannot be achieved by RT-PCR. Since the pandemic outbreak, various mass spectrometric approaches have been developed for rapid detection of SARS-CoV-2, including the LC-MS/MS approaches that could allow analysis of several hundred clinical samples per day with one MS system, MALDI-MS approaches that could directly analyze clinical samples for the detection, and efforts for the on-site detection with portable devices. In this review, these mass spectrometric approaches were summarized, and their pros and cons as well as further development were also discussed.

Establishment of a spectral database for classification of edible oils using matrix-assisted laser desorption/ionization mass spectrometry.

In this study, we aim to establish a comprehensive spectral database for analysis of edible oils using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). More than 900 edible oil samples, including 30 types of edible oils, were analyzed and compared, and the characteristic peaks and spectral features of each edible oil were obtained. Edible oils were divided into eight groups based on their characteristic spectral patterns and principal component analysis results. An overall correct rate of 97.2% (98.1% for testing set) was obtained for classification of 435 edible oil products using partial least square-discriminant analysis, with nearly 100% correct rate for commonly used edible oils. Differentiation of counterfeit edible oils, repeatedly cooked edible oils and gutter oils from normal edible oils could also be achieved based on the MALDI-MS spectra. The establishment of this spectral database provides reference spectra for spectral comparison and allows rapid classification of edible oils by MALDI-MS.

High-temperature, high-pressure hydrothermal synthesis, crystal structures, and spectroscopic studies of a uranium(IV) phosphate (Na10U2P6O24) and the isotypic cerium(IV) phosphate (Na10Ce2P6O24).

A uranium(IV) phosphate, Na10U2P6O24, was synthesized under hydrothermal conditions at 570 °C and 160 MPa and structurally characterized by single-crystal X-ray diffraction. The valence state of uranium was established by UV-vis and U 4f X-ray photoelectron spectroscopy. The powder sample has a second-harmonic-generation signal, confirming the absence of a center of symmetry in the structure. The structure contains UO8 snub-disphenoidal polyhedra that are linked to monophosphate tetrahedra by vertex and edge sharing such that a three-dimensional framework with intersecting 12-sided circular and rectangular channels is formed. All 10 sodium sites are situated inside the channels and are fully occupied. This is the first uranium(IV) phosphate synthesized under high-temperature, high-pressure hydrothermal conditions. The isotypic cerium(IV) phosphate, Na10Ce2P6O24, was also synthesized under the same hydrothermal conditions. It is the first structurally characterized Ce(IV) phosphate with a P/Ce ratio of 3. Crystal data of Na10U2P6O24: orthorhombic, P212121 (No. 19), a = 6.9289(3) Å, b = 16.1850(7) Å, c = 18.7285(7) Å, V = 2100.3(2) Å(3), Z = 4, R1 = 0.0304, and wR2 = 0.0522. Crystal data of Na10Ce2P6O24: orthorhombic, P2(1)2(1)2(1) (No. 19), a = 6.9375(14) Å, b = 16.215(3) Å, c = 18.765(4) Å, V = 2111.0(7) Å(3), Z = 4, R1 = 0.0202, and wR2 = 0.0529.